New book is emerging. Takeoff with Captain Doug: Flight Deck Disclosures

It’s 90% done. Here is my chapter dedicated to weather. No, it is not geared to the well informed, “top-of-their- game-pilot” but more so for the travelling public. The book is in American English to cater to the god bless American dollar.

Chapter 8 Weather Stuff 

Update. The book file has been sent to a publisher today, October 10th/2019. Fingers crossed!

Can clouds foretell flight conditions?
Clouds do foretell flight conditions. Billowy, puffy clouds signal a bumpy ride ahead, while clouds based a few thousand feet above the ground typically give way to smooth conditions when climbing above. Usually, layered clouds also lead to a steady ride. An experienced eye can recognize clouds that are associated with a weather phenomenon. Even fog, a cloud based at the ground, renders six atmospheric processes. The shape of the streaks that form from another aircraft’s exhaust at higher altitudes can tip off pilots to flight conditions. I’m always attuned to the telltale signs of clouds, but that could just be the meteorologist in me.

By knowing how they form reveals the process transpiring in the atmosphere. Day time heating will cause air to rise creating puffy cumulus cloud meaning bumps. It’s those clouds you learned to draw in elementary school. Sure, these puffy white billowy clouds have a cute appearance but they can pack a punch especially when they grow taller and fatter becoming teenage and adult equivalents.

Layered cloud usually infers smoothness. A mackerel sky, appearing like the scales of a fish, is high based cirrus cloud, called cirrocumulus. This implies possible bumps from a fast-moving jet stream. Clouds also cause ice on airplanes, reduce visibility near the ground, and clouds forming aft of our jet engines called contrails, will foreshadow advancing weather if they take a long time to disperse. Many think the nomenclature of clouds is extensive and difficult. Not so. By learning your clouds, you are indirectly learning flight conditions.

Clouds in my sky

The idiom, “Being on Cloud Nine,” is an oxymoron. This billowy, lofty, puffy, cotton-batten-like cloud exudes pleasantry and is labelled #9 on the cloud chart, called cumulonimbus. But it’s a wolf in sheep’s clothing and pilots know to avoid it all costs. Think thunderstorm.

There are low, middle and high clouds and clouds of vertical development. I am constantly querying the shape, intensity and the process as to why clouds are there. It helps me find you smooth rides. Clouds are either composed of liquid water droplets, supercooled water droplets, ice crystals or all the above. Those high thin wispy clouds called cirrus, a.k.a mare’s tails, is composed entirely of ice crystals. Flying in cloud below zero Celsius may cause ice to form on an aircraft. Water can exist in liquid form in clouds well below freezing, in fact all the way down to frigid - 40° C (-40° F, yes, they are the same at this value). At that point, meteorologists coin it homogeneous nucleation.

In 1802, Englishman Luke Howard, a pharmacist by trade, gave clouds the common names we still use today. He noted three basic shapes of clouds: heaps of separated cloud masses with flat bottoms and cauliflower tops, which he named cumulus (the Latin word for “little heap”); layers of clouds like blankets, much wider than they are thick, which he named stratus (Latin for “layer”); wispy curls, like a child’s hair, which he called cirrus (Latin for “curl”). To clouds that generate precipitation, he gave the name nimbus/nimbo (Latin for “rain”).

Cirrus (Ci) Cirrus clouds are high, thin, wavy, wispy, fibrous tufts of white cloud. These fibrous bands can take the shape of horse tails; thus, they are sometimes called mares’ tails. They indicate fair weather, but if they start to thicken, inclement weather is approaching. Cumulus clouds due to daytime heating, form and reform in about 10 minutes. Try watching it transpire on time lapse photography.

Why the bumps?

Nearly twenty-two years ago, my first article for enRoute ¾ my company’s inflight magazine ¾ explained the seven types of turbulence titled Why the Bumps? This is the most commonly asked question and concern from passengers. Technology has certainly helped to contend with the unpredictable nature of bumpy rides. A pilot’s iPad can now superimpose a specific routing on weather charts that depict areas of bumps. We can also interrogate other airplane reports from this site. These ‘heartbeats’ show the whereabouts of the airplane, its altitude and whether bumps occurred during the flight. Our flight plan also assigns a numerical value for possible bumps along every waypoint, while flight dispatch sends us inflight reports via datalink. Everyone is striving to deliver the smoothest ride possible.

Turbulent times 

AIRPLANE SMILEY   Physicist Theodore von Kármán is credited with saying, “There are two great unexplained mysteries in our understanding of the universe. One is the nature of a unified generalized theory to explain both gravity and electromagnetism. The other is an understanding of the nature of turbulence. After I die, I expect God to clarify the general field theory to me. I have no such hope for turbulence.”

My flight plan denotes a number from zero to nine for each navigation point along the route. A zero or one means things should be smooth, but when numbers three, four and five appear the seat belt sign is likely to be illuminated. Many think there is a device that automatically turns on the seat belt sign when bumps occur, but it’s strictly subjective and done with the concurrence of the captain.

 AIRPLANE SMILEY     Finally, the internet has made its way into the flight deck. For a few years, the internet was only available in the cabin due to technical reasons. I jokingly averred I could go to a passenger in business class during the flight and ask him what the weather is doing up ahead. Now, I don’t have to.

Is there any way to detect and detour around severe turbulence?

Policy and common sense is to avoid or circumnavigate known areas of severe turbulence, especially thunderstorms. Most airliners also have wind-shear detection systems to detect shearing winds near the ground. It does not detect high level wind shear. No device detects turbulence due to jet streams, but weather maps depict and forecast all types of turbulence. Flight dispatchers will avoid such areas or plan flights at different altitudes. Sometimes this is all it takes to ensure a smooth ride.

 AIRPLANE SMILEY   Dear Mr. Morris.  Whenever I fly, the second I sit down I reach for the EnRoute magazine and your article of the month. I am a very, very nervous flyer, often to the point of tears. I often want to drive to Vancouver and even risk the Coquihalla in the winter. My fear of flying has greatly impacted our travel plans much to my husband's dismay. And, yes, it is usually associated with turbulence.  Therefore, I was very happy to see this article.  I live in Kelowna, BC and most of the time I am leaving here it is on a prop airplane.  It isn't the prop I mind so much, although I would prefer a jet, it is the fact that almost all the time coming in and out of Kelowna, there is turbulence.  Not just a bump or two, often I fear we are going to fall from the sky it is so rough. And often, the weather appears just fine.  So, I don't get it.  Having said this, the last time I flew 1 1/2 weeks ago from Vancouver to Kelowna the captain made an announcement prior to take off to say that it would be rough going in to Kelowna but nothing to worry about.  Just hearing his calm announcement and his reassurance that this was all quite normal, helped me tremendously.  I can't tell you the difference it made in my short flight home.  That is only the second time I have ever heard from the cockpit in many years.  Usually there is nothing said at all.  When I got off the flight, the captain was standing in the cockpit doorway and I told him exactly how much I appreciated what he had said.  It took so little time and meant so much to me and I am sure others.  Susan 

Is turbulence dangerous? No and sometimes yes. Any airliner must be built to handle any amount of turbulence, but no sane person wants to challenge this extreme realm. Yes, you will see the wings flex up and down as they contend with the rough air. This is normal, although for most, it is disconcerting. The danger arises when passengers don’t have their seatbelts fasten as rough turbulence can suddenly appear catching many off guard. It can toss you about violently, and if items are not secure, act as projectiles. People try to get comfy by undoing their seatbelt or allow a child to sleep on the floor. They are the ones injured when mother nature starts throwing nasty punches. Over my entire career, I can count on one hand, okay maybe two, where things got scary rough. I admit, I am a wimp when it comes to rough air and for you as a passenger this is a good thing.

Many passengers get a false impression when the seatbelt sign is illuminated and yet the flight attendants are going about their business. Some pilots turn on the seat belt sign at the onset of the first ripple envisioning lawsuits if they don’t illuminate the sign but deciding when to put the sign on is purely subjective. For a long haul flight the seatbelt sign may cycle on and off ten or more times. This on again, off again trend can bestow a laissez-faire approach among passengers.

And don’t think pilots are up in the flight deck saying nonchalantly, “oh well.” We too don’t like rough air. Its annoyance wears on everyone. Our job is to get you to your destination safely and expeditiously. No one likes turbulence, including pilots!

 AIRPLANE SMILEY  Part of our mandatory briefing with the in-charge flight attendant includes reporting on expected ride conditions. One day, the in-charge flight attendant quickly intervened, saying, “I know, I know. . .it’s going to be smooth between the bumps.”

Doesn’t a weather radar detect turbulence? On-board weather radar detects precipitation, which, if significant, implies turbulence because the air is unstable and moving about to cause a bumpy ride. In the nose of every airliner is where the weather radar and antenna is fixed. The nose cone, called a radome (radar dome), can be hinged opened on the ground to inspect the weather radar. Weather radar honed from WWII technology, is a great detector of rain, however, other types of precipitation reflects less energy back so a pilot must challenge these “returns.” Generally, light precipitation is depicted (painted) as green, heavier rain is yellow with red as heavy to extremely heavy. Some radars paint magenta for the extreme category. Pilots want to avoid all returns. But red should be avoided at all costs and rest assured the seat belt sign will be illuminated. This is no place for any airplane and pilots know it. We want to avoid, avoid, avoid but sometimes pilots get into tight situations and things can get rough. One recent frequent flyer nearing the million-mile category, asked if air traffic controllers purposely vector pilots into bad weather because of constraints. They will try their best not to do so, but sometimes a pilot must weigh the consequences. This is not a good predicament and it’s not where anyone wants to be.

 AIRPLANE SMILEY     One of the best methods still to this day for avoiding showers, heavy rain and turbulent cloud is with a pair of eyeballs. You’ll find me scanning the sky and at night with the flight deck lighting turned down and acutely looking outside. 

What’s a jet stream? (sky snakes)

We all probably have some vague notion of what a jet stream is, those streaky white trails that appear behind high-flying jetliners? Well, no, that’s a common misconception. Those are condensation trails formed by the exhaust of aircraft jet engines. Jet streams are a much more spectacular phenomenon — long, thin bands of extremely fast-moving air that form at high altitudes and corkscrew through the atmosphere around our planet.

In 400 BC, Aristotle wrote a treatise on weather entitled Meteorologica, in which he noted that higher clouds may move faster than lower clouds. Over 2000 years later, when manned balloons were first launched during the 18th century, those aboard noticed that winds tended to increase with height. But it wasn’t until World War II and the advent of high-altitude flight that jet streams were encountered and their presence confirmed.

On November 24, 1944, 111 U.S. Air Force B-29 bombers were sent from the Pacific island of Saipan to attack industrial sites near Tokyo, Japan, in the first high-altitude bombing mission of World War II. As the airplanes approached the island of Honshu at 33,000 feet (10,058 m), they were suddenly hit by winds of 140 knots (161 mph or 260 km/hr), which knocked them completely off course. Only 16 of the 111 pilots managed to hit their targets, while the rest were blown over the ocean and forced to return to base. Pilots on subsequent missions also reported encountering extremely powerful winds and unexpected turbulence when flying westward to Japan. What were these incredibly strong winds? One pilot likened them to a jet of air streaming out of a hose with enormous velocity; hence the name jet stream.

We now know that jet streams are produced because of the significant temperature changes where air masses collide. In North America, for instance, where there may be four distinctive air masses, up to three separate jet streams would exist. They can be hundreds of miles long, tens of miles wide and a few to several thousand feet thick. (I liken their dimensions to a Christmas ribbon when teaching my weather classes). They migrating southward in winter and decrease in altitude the further north they are found and flow at different heights depending on the season. Jet streams are strongest during the winter months because the frontal zones or temperature differences between air masses are more dramatic in winter. They mark the dividing line between seasonable and unseasonable temperatures. They also indicate in what direction and at what speed surface weather (highs, lows, fronts, etc.) is traveling.

To locate jet streams, weather balloons are sent up to penetrate the higher atmosphere, climbing to 100,000 feet (30,480 m). As well, airliners have equipment onboard to gauge upper atmospheric wind conditions, and satellites capture some of the telltale cloud patterns associated with jet streams. It’s a fast-moving current of air that circulates around the Earth in a corkscrew motion at altitudes of 25,000 to 45,000 feet. A jet stream’s speed and momentum are affected by the varying temperatures in the southern and northern latitudes as well as by the Earth’s rotation. Average high speeds are between 100 and 180 knots. The force of a jet stream often leads to quicker flight times by creating what pilots refer to as “push.” A flight from New York to Los Angeles can take five hours, but with the effect of a jet stream, the return trip can be reduced by 40 minutes. 

Sometimes a pilot will want to get into this fast-moving air; at other times, he or she will want to avoid it. We try to capitalize on strong tailwinds and, if able, duck out of the stronger than normal headwinds. If any turbulence is detected, pilots always ask for ride reports from air traffic control and then climb or descend to find smoother air. On occasion, this air can also be rough and become so quickly, which is why regulations have you keep your seat belt fastened at all times.

AIRPLANE SMILEY    Robert Buck, in his iconic pilot weather book, Weather Flying, 1998, described the elusiveness of high-altitude turbulence this way: “Meteorologists can locate the jet stream rather accurately, they cannot pinpoint exactly where the turbulence will be. They can tell you in general terms. I can assure you that sometimes it will be rough when they say it won’t and smooth when they say it will be rough.” To this very day, it remains a hard and fast observation.

Aurora Borealis – northern lights (dawn of the north)

Winter’s long nights and frequent clear skies in northern latitudes renders fantastic views of the dancing light show some 60 miles above. Charged particles released from the sun (solar wind) collide with the Earth’s magnetosphere. This causes earth’s oxygen to yield a pale green or pinkish display. Higher up, about where the space shuttle cruised (200 miles), nitrogen promulgates blue or purplish-red. Many of our flights take in this awesome display so keep your window shades open to catch Mother Nature’s free light show.

Facts: The northern lights dazzle about the earth’s magnetic poles, so northern Canada (where the magnetic pole is located) is privy to some of the best shows especially the Yukon, Nunavut and the Northwest Territories. The southern lights are known as Aurora Australis.

Santa Claus operates from the geographic North Pole, but the Aurora Borealis centers around the magnetic pole — some 500 (800 km) miles away. 

On many northern flights, I’ve witnessed the many guises of the dancing northern lights — from docile patches of light, bursting streamers, arcs and undulating curtains, and spiking rays sometimes with ominous glows.

When Mother Nature sets up her stage full of lights we frequently ask flight attendants to visit the flight deck to take in the show.

Wind beneath our wings

Wind direction dictates the runway used for takeoffs and landings because flight into the wind (headwind) enhances performance. But frequently winds blow across the runway (crosswind) with each aircraft having inherent limits on wind speed and runway conditions. Don’t be alarmed if you see a pilot finesse a landing briefly touching on one main wheel because that’s how crosswind landings are performed. Winds generally increase with altitude, so much so, they can surpass hurricane strength due to jet streams. Winds can suddenly change in direction and/or speed called wind shear. But near the ground onboard devices warn pilots of this, plus many American airports have a system forewarning shearing winds. In Canada, this warning system does not exist.

 Wind facts: Maximum tailwind and crosswind limits for an autoland is 10 knots and 15 knots, respectively.

Winds are reported and forecast in direction of true north, but Air Traffic Control state them in relation to magnetic north because runways are orientated in magnetic.

I’ve been in winds clocked at 220 knots (400 km/hr) at cruising level.

The minimum speed to constitute a jet stream in Canada is 60 knots. In the U.S.A and Britain, it’s 80 knots.

Maximum crosswind (90-degree angle) limit for the B787 I fly is 38 knots. That is gale force strength.

Pilot Glory

Pilot Glory

The device that measures wind speed and direction is an anemometer. Strictly speaking an anemometer measures wind speed, but colloquially it’s a device that determines both speed and direction.

The measurement of wind is observed at 10 meter (33 feet) heights at airports around the world.

Wind speed is measured in knots in the aviation world except China, Mongolia and Russia where meters per second is used.

Wind is referenced to where they are coming from. Not where they are going. A south wind means it is blowing from the south.

Every airliner has wind readout and groundspeed to see how fast we are moving across the ground due to winds.

Iconic singer Bob Dylan claimed, “You don't need a weatherman to know which way the wind blows.” But in aviation you do!

Upper level winds (crucial for flight planning) are derived from weather balloons from over 900 stations around the world launched twice a day.

Data from aircraft, called AMDAR (Aircraft Meteorological Data Relay), is used to drive the weather supercomputers to forecast wind at all flying levels around the world.

Technique for keeping the aircraft tracking straight during a crosswind landing, “turn into the wind and apply opposite rudder.”


I noticed a circular rainbow with the shadow of the airplane inside it. How does it occur?

A “glory” forms in moisture and the larger and more uniform the better. These droplets act like little prisms scattering out the primary colors and bending them back to you, the passenger. You also need the sun behind you, with the aircraft eclipsing a shadow in the center as a bonus. When an aircraft’s shadow is seen to dance inside, it’s called, “The glory of the pilot.” Glory may be a precursor to possible air frame icing. Pilots don’t like flying very close to cloud tops for two reasons. Described as “bouncing on the tops” implies a bumpy ride and potential airframe icing.

The Deice Man Cometh (Taking it off and keeping it off)

As you sit comfortably in your seat, take a moment to notice ground crew working outside in freezing temperatures. They appear to be washing the airplane, but they’re ridding the wings and sometimes the fuselage of ice and snow. This procedure is deicing and is necessary for departure, as airline safety standards prohibit takeoff when ice, frost or snow is adhering to the airplane. But why?

Many think it’s because it adds weight, but the main culprit is it disrupts air to smoothly flow over the wings and it increases drag. The captain is ultimately responsible, but the lead ramp attendant must also be in concurrence. Even flight attendants and passengers can voice concerns.

No place better illustrates deicing than the CDF (Central Deice Facility) at Toronto’s Lester B. Pearson airport – the world’s largest.  This 65-acre “drive-through airplane wash” consists of six huge bays subdivided into three capable of handling hundreds of aircraft daily. Official deicing season is October 1st to April 30th. Because this is a “live” or “engines running” operation precise terminology and electronic signboards are used to keep things safe. Pilots contact the “Iceman” in the deicing control tower appropriately named the “Icehouse.” Once in position, two expensive ($1.4 million each) made in Denmark vehicles called the Vestergaard Elephant Betas (the facility has about 40 of them) springs into action. The deice procedure involves spraying an orange deice Type I fluid composed of hot water and glycol to rid the ice and snow. If precipitation is falling or imminent, it is followed up with a cold application of a bright neon green anti-icing Type IV fluid to stop precipitation from sticking. The “throughput” time for an Airbus 320 is an amazing 12 minutes. For a light snow event, it takes about 300 L of Type I at a cost of 1$ per liter and 250 L of Type IV at 2$ per liter plus a $350 visit fee. This is all part of doing business in winter.

Is weather getting worse? Is turbulence more intense? Are thunderstorms higher?

If you fall for the “CNN Effect” then you will be convinced turbulence is more frequent and more violent. I can’t give a definitive yes or no, but just maybe. Mother Nature must balance the books and that includes the heat budget. For jet streams to be stronger it would mean temperature differences are increasing i.e. the North pole is getting colder and further south is getting warmer. For thunderstorms to get bigger means the layer in which we live, the troposphere, is getting higher. I’m not so sure. But expect more articles to infiltrate the media. We’re going to learn more terms, hear more opinions and surveys as we did for the “polar vortex” and the “cyclone bomb.”

How in the heck do you land in next to zero visibility? Foggy Landings

Have you ever looked out of an airplane window as it descends, and you go lower and lower, and wonder when, and if, the ground will appear? Many of us have probably been on flights like this, but just how do pilots find the runway?

A Pilot’s Approach

Despite what seems to be a precarious situation, commercial, and some private, pilots routinely fly safely into clouds with the aid of instruments. A handful of different instrument approaches are currently available, but the most precise and preferred approach is the ILS (Instrument Landing System), which provides both vertical and horizontal guidance in low-cloud conditions, fog, rain, snow, haze, and other obscuring phenomena.

How does it work? A localizer signal at the far end of the runway guides the pilot or autopilot in a straight line toward the runway, while a glide-slope signal on the sides of the runway leads the aircraft down vertically. An easy way to visualize this precision approach is to picture a children’s slide at a park. The aircraft flies at altitude just as a child sits on top of the slide. The airplane is then eventually steered in the direction of the runway, whereby the flight deck instruments lock on to both the localizer and glide-slope signals. When the aircraft is locked onto both signals, it is as if the airplane is in the crosshairs of a rifle. On board, sophisticated autopilots guide the aircraft all the way to the ground, automatically compensating for changing winds and other variables. The precision approach guides the pilot down to his or her landing sight (the runway), just as the slide guides the child to the landing. A localizer provides left–right orientation with the runway, like the sidewalls of the slide. The angle of this approach is typically three degrees. It’s the angle you may have noticed airplanes maintain while following one another on approach to a busy runway. The glide-slope signal guides the aircraft down vertically, and the auto-thrust system adjusts engine-power settings to ensure proper speed, even bringing the engine to idle at touchdown.

Other important features of ILS

Several other components augment the ILS and provide additional safety features for low approaches. These include devices that transmit exact distances from the runway, high-intensity runway and approach lighting (the intensity ranges from a dim setting of one to power-zapping strength five), and radio-beacon markers that transmit important distances to the pilot. One such marker is called the FAF (Final Approach Fix, which is typically located 4 to 6 miles (6.4–9.7 km) from the airport. At this point the pilot should have the landing gear down, a clearance to land from the control tower, and final flap settings for landing. Sitting by itself is a RVR (Runway Visual Range) sensor along the edge of the runway. It measures distance seen through obscuring weather phenomena in units of feet, and it gives a very accurate idea of what a pilot can expect to see, or not see.

Not all ILSs are created equal

There are three different categories of ILS, differentiated by the DH (Decision Height) and prevailing visibility. DH is the indicated altitude at which a pilot must decide to either continue the approach to a landing or abort it and go around. A category I ILS (the least accurate) has a DH of 200 feet (61 m) above ground. Most large airports around the world have this type of ILS. DH is determined by a barometric altimeter, which the pilot must adjust to the most recent pressure reading at the airport. Every pilot knows just one-tenth of a change in pressure in inches of mercury translates into a discrepancy of 100 feet (30.5 m).

A category II ILS has a lower decision height, 100 feet, and it determines height with a device that bounces signals from the airplane to the ground and back, called a radar altimeter (or radio altimeter). It allows the airplane to descend with a higher safety margin. The last, but certainly not the least, is the category III approach.

Welcome to Autoland

Category III ILS (autoland) has two levels. The first level brings the aircraft to a mere 50 feet (15.2 m) above the runway, at which time the pilot must make a snap decision. The second fully automated level has no decision height, meaning pilots do not look outside and wait for the bump. It is a procedural necessity: pilots looking outside could cause disorientation. Complete faith is bestowed in the system, which admittedly takes some getting used to. A gamut of requirements must be met to allow such an approach. The ground facilities must have high-intensity runway lights, centerline lighting, various markings on the runway, additional RVR sensors, and backup airport emergency power to ensure the runways and taxiways are lit up and the ILS is functioning, even during power outages. On board the aircraft, sophisticated autopilots bring the aircraft to the ground, automatically correcting for winds all the way to the touchdown. Only major airports have such a system, with most only having the system on one runway. (Vancouver, Toronto and now Calgary and St. John’s, Newfoundland (the one that needs it the most) have the only category III runways in Canada. Pilots must be certified to do autolands, requiring checkouts in flight simulators every six to eight months. The airline company and aircraft must also be certified for autolands. As you can see, there are a lot of parameters that must be met, clearly separating the amateurs from the pros.

For airliners, an autothrust system adjusts engine-power settings to ensure proper speed is obtained. In fact, it will even bring the engines to idle at touchdown. An autobrake system supplies the correct amount of braking at touchdown to stop the aircraft. As well, there are many computers that monitor the aircraft systems to ensure everything is functioning at 100 percent. They even make synthesized altitude call-outs to the pilots.

Waiting for the bump

The absolute minimum visibility for a category III landing is less than the length of a football field, with next to nothing to see when approaching at speeds of 150 knots (173 mph or 278 km/h). Once air traffic controllers clear the aircraft for a category III approach, the pilots attentively monitor the automatic systems, overpowering the urge to look outside, and patiently wait for the bump. Even with the main landing gear firmly on the runway, the flight deck may still be mired in fog because of the landing angle. From ab initio training, pilots are taught to trust their instruments; still, autoland bestows a much higher level of faith in technology.

Because the system is so accurate, the automatic pilot must be disengaged after landing or else the aircraft will try to reposition itself back on the centerline of the runway. Finding the terminal building in such heavy fog can be a difficult task, but many airports have bright green lights embedded in the taxiways to guide the pilots to the gate or “follow me” vehicles.

The autoland system truly is a marvel of technology and exemplifies just how technically advanced aircraft and airports have become. Nothing can replace the skill of an experienced pilot, but when extremely poor visibility dictates a category III autoland, technology rules.

Contrails or chemtrails?

Man-made clouds may form behind an aircraft, produced by the moisture of combustion exhaust saturating the air and causing condensation. Two by-products of hydrocarbon combustion are carbon dioxide and water vapor. For each pound of jet fuel burned, about 1.4 pounds of water vapor is produced. Many believe that the contrails we see in the sky are pollution, but they are

mostly frozen water. The vapor condenses into tiny water droplets, which freeze if the temperature is low enough. These millions of tiny water droplets and/or ice crystals form contrails. The exhaust particles act as a trigger, causing the trapped vapor to rapidly condense. Exhaust contrails usually occur above 25,000 feet, and only if the temperature there is below −40° C (− 40° F).


Conspirators, akin to the flat earth society, are adamant these white ice crystal streaks are chemtrails (chemical trails) imposing harm. It is said, don’t believe everything you read on the internet and this is one of them.  

Our Atmosphere


Standard Atmosphere_colour.jpg

Four main layers of the atmosphere exist. We live in the troposphere where most weather occurs but your flight may also take you into the second layer, the stratosphere. The boundary between the two layers is deemed the tropopause. Pilots abbreviate and reference it as “trop” but it rhymes with “rope.” This interface is known to where turbulence lurks. It acts like a lid to most weather more specifically thunderstorms and is where jet streams corkscrew around the globe. It’s coincidentally where jet engines are most efficient. Because of it, pilots always want to know the whereabouts of the tropopause. It raises in the summer, lowers to the north and raises in southern latitudes. It also changes day by day according to the weather systems. Statistically it hovers around 36,000 feet, but elevates to 55,000 toward the equator thus higher thunderstorms. A pilot’s flight plan includes the location of the tropopause and is specified to within feet at every waypoint along the way.


Humidity. Amount of water vapor contained in air

Most find it hard to fathom that moist air is less dense than dry air, thus the air on a hot humid summer day is less dense than a cold dry winter’s day. That’s because there are fewer air molecules in a given volume of warm air than in the same volume of cooler air. This thinner air plays into aircraft and jet engine performance because when thinner air flows over a wing it means less lift, and thinner air in a jet engine means less thrust.

In 1965, Canadian meteorologists developed the Humidex, to describe how hot and humid weather feels by combining the effects of temperature and humidity into one number equivalent temperature.

The humidity of cabin air in standard aircraft is derived from conditioned air ducted from the engines, has humidity levels equal to desert air (5%). The new B787 Dreamliner, however, provides a more humid cabin allowing a more restful flight with 15% humidity. Cabin air pressurization is provided by electrically driven compressors, eliminating need to cool heated air from the engine and the cabin’s humidity is programmable based on the number of passengers carried.

An aviator will learn fog has many guises. In fact, there are six mechanisms whereby fog will form. One of the foggiest airports on the planet is on Canada’s east coast, St. John’s, Newfoundland where visibility will drop to a half a mile or less nearly one third the year ¾ 120 days. Fog will form when: air moves up a hillside, as warm air moves over a cool surface, when cool air advects over warm water, in frigid temperatures, when it rains, and overnight under clear skies and light winds. Fog’s less restrictive counterpart is mist. Weather observations abbreviates it as BR (some refer it to “British Rain”) which stems from French meaning Brume. Here is my poetic attempt to explain the six types in pilot prose.



It prances in diverse guises

It marks its misty presence as it ascends a hill little by little

As a warm wind moves over chilly waters it will form an immense white blanket

It can stay for days and wilt a spirit

Or appear at dusk and ebb at dawn

It may accompany a gale obscuring a pilot’s line of sight to mere feet

It can ally with raindrops inducing low visibility

                                     Or play havoc in bitterly cold Arctic air

It can be a sign of seasonal change as it lunges from warm water

But no matter its genesis... it will challenge any aviator…

- Captain D


Can it be too hot to fly?

You’ll be hearing more and more about this as we progress into global warming. Recently, many flights were cancelled in southwestern USA because of the heat. Much of the southwest is higher in altitude also contributing to thinner air. One saving grace is the air is drier. Dry air is denser than moist air. You’re probably asking, why is that since I can see moisture like fog, mist and haze so shouldn’t it be denser? Nope. Water (H2O) weighs less than nitrogen, the main constituent of air.


Thus, it can be too hot to fly, as air is less dense and when it gets extremely hot, aircraft takeoff calculations will forbid safe departures. Every airliner in the world must have a balanced field in case of a rejected take off on the runway so it can come to a safe complete stop. When higher speeds are required to produce enough lift to get airborne then this balancing act for takeoff speeds becomes a major player. One way is to reduce the weight meaning less passengers or leaving cargo behind.


AIRPLANE SMILEY    Years ago, during the heat of India, the temperature hovered at 31° C (88° F) near midnight being too hot for a safe and legal take off. When it cooled to 30° C (86° F), we were good to go. It still made for an interesting take off with the aircraft laden with fuel required for a 15-hour flight and a full load of passengers.


You’ll find many airlines in the middle east operating most of their flights during the wee hours of the night as temperatures are somewhat cooler. Luckily for them, most airports sit at elevations near sea level. On that note, airports sitting in higher elevations can be problematic. Denver (Mile High City), Mexico City and Bogota (our highest airport elevation) offers challenges. Luckily for Denver they have some of the longest runways in North America. It’s also why Calgary, Alberta has the two longest runways in Canada because it sits at an altitude of over 3,600 feet above sea level where Vancouver on the other side of the “Rocks” sits at 13 feet above sea level.

One also must factor in ground operations. The heat can be dangerous to ground personnel especially in the belly of the airplane. Animals would perish in the heat so restrictions are implemented. As well, airliners themselves have temperature limitations as they must keep certain components cool such as the avionics. If the on-board air conditioning units or supplied ground air can’t keep up, then boarding will be denied.

AIRPLANE SMILEY      Years ago, while sitting at the stand (they call gates stands) in London, England our air conditioning unit was not working. The captain refused to allow boarding until we had acceptable air conditioning, but none was available. One would think London of all places wouldn’t be an issue with suppressive heat. Luckily, I convinced the captain to allow boarding or else the flight would have been canceled.

Can it be too cold to fly?

Cold air means denser air and is welcomed to any aviator. Cold air produces more lift over the wings and more thrust from the engines and propellers. But to start an engine requires temperatures above -40° C (-40° F) so they would have to be preheated. The airplane itself is used to cold temperatures as it hovers at - 57°C (-71° F) at cruising altitude. Again, it is the ground personnel that are challenged during extreme cold. Machinery won’t start, the heaters are less effective, even getting potable water to the airplane can be an issue as well as cabin doors freezing shut.

 AIRPLANE SMILEY     While arriving in Edmonton, Alberta during the middle of winter in a extreme cold snap, the wheels to the jetway froze. The rampies took 20 minutes to thaw out the frozen wheels. Winter operations are a challenge. While trying to push back from the gate in Stockholm, Sweden the push back tug spun its wheels to no avail. Another heavier tug equipped with chains came to the rescue.

Is lightning bad and is it detrimental?

Many of us envision those B rated Hollywood movies where an airplane is in a turbulent ride flying in and out of dark ominous clouds, when suddenly, a lightning strike knocks part of the wing off. Lightning will enter the aircraft and exit with no damage (usually), however, it may leave little pinholes or burns during its transit. Statistics show an airliner gets hit every 5,000 hours or about once a year. The FAA estimates every airliner in the U.S will be struck once a year. Aluminum is an excellent conductor, but some airplanes made of composite may experience lightning strikes a little more (Did I tell you I fly the composite B787?). If we do get christened with an electric jolt, it will mean the aircraft must be looked over with a fine-tooth comb by maintenance.

 AIRPLANE SMILEY  On my first flight released to the line as captain on the B787, the first officer looks over at me and mentions the slightly higher probability of lightning strikes with the B787. Guess what transpired that same day on the return flight from Los Angles to Toronto? I had to write up a lightning strike event in the logbook when we landed. Having said that, I’ve been flying the B787 for nearly two years since that episode ¾lightning free. Did I just jinx the weather gods?


St Elmo’s Fire

St Elmo’s Fire

St. Elmo’s Fire

Now and again, pilots will witness a static build up on their windscreens looking like dendritic fire strokes. Truth be told this dancing marvel is harmless, however the static build up is usually a sign that nearby thunderstorms are lurking which are not so harmless. Volcanic ash will also cause St. Elmo’s fire. Passengers may see this phenomenon around propellers or near the intakes of the jet engines. Frequently, we invite flight attendants up to the flight deck to witness this vibrant light show.

How high can thunderstorms get?

Most thunderstorms range from 30,000 to 55,000 feet with some topping to 65,000 possibly 70,0000 feet. Maximum altitudes for airliners are at 39,000 to 43,000 feet meaning we can only fly over the smaller monsters. Most turboprops get as high as 25,000 feet. And that’s what a thunderstorm aka cumulonimbus is, a meteorological monster! Even when flying over these deathtraps we try to give as much berth as we can. Flirting with the top on a thunderstorm is a bad idea. Small business jets have the capability of getting as high as 55,000 feet, but they too exercise caution with flying near these nasty clouds. It’s equivalent to driving into a 10-foot deep pothole. They still make me quiver when I brush up near them. Why so close you ask? Well there are thousands of thunderstorms per day with 2,000 booming at any time around the globe so their presence is inevitable. I prefer winter season in North America over summer for that reason alone, because these bad ass clouds are less frequent.

AIRPLANE SMILEY    I still get apprehensive when nearing these weather beasts, especially when I am at 30,000 feet and only half way up alongside these meteorological monsters. It’s like a small boat coming alongside a massive ocean going ship. Just the ripples alone could capsize the boat. It’s dark and ominous presence must always be respected.

 AIRPLANE SMILEY   One of the biggest fears for an airline captain is making the news because of an incident. Without a doubt, it enters the equation during significant turbulence and only escalates the angst. Social media is now the new “six o’clock news” and one doesn’t have to be reminded almost every passenger has a smart phone, iPad or some other recording device. And with onboard internet, one doesn’t have to be on the ground to hear what has transpired. Airlines realize this and now have devoted teams to deal with issues.

April 2019

I started enRoute 21 years ago talking about turbulence. I thought it appropriate to explain about bumps some 21 years later.

Yes, they only drew three stripes. Well the tunic could be a cruise pilot, relief pilot or a first officer upgrading to captain.

Yes, they only drew three stripes. Well the tunic could be a cruise pilot, relief pilot or a first officer upgrading to captain.

Pouring a Guinness

What does beer have to with weather?


Captain D the bar tender

Learning to properly pour a Guinness.

How does beer and weather mix? Well, I learned the temperature for making a perfect Guinness starts at 232 degrees Celsius.

Second, my grade nine teacher pointed out that London, England is much farther north than many cities in Canada, but it is much warmer at the same latitude. Dublin, Ireland (Guinness capital of the world) is the same latitude as Goose Bay, Labrador at 53 degrees north. But Goose Bay can be -15 C whereas Dublin will typically be +15 C. Why the huge difference? Think…Gulf Stream.

In January, 2019 a United B777 diverted into YYR (Goose Bay ) due to a “medical.” The temperature was -30 C so one of the cabin doors would not close. Passengers were left to sit on the plane and cycle through the small, inadequate airport facility. Can you say “gong show?” Another exemplification that medical diversions are a challenge. And then some!

Now back from a Dublin vacation and I’m off to Sao Paulo tomorrow. Last time there, I diverted into Brasilia for a medical. Yes, another gong show. I sure hope the three year old boy is doing well.

United delayed for 20 hours in Goose Bay, Labrador.

United delayed for 20 hours in Goose Bay, Labrador.

Beware of the southwest flow aloft!

Meteorological history repeats itself.

Surface analysis depicting a weak low pressure spreading an easterly flow over southern Ontario. An upper trough supporting this low, spread 25 to 45 knot southwest winds aloft at 3,000 to 5,000 feet.

Surface analysis depicting a weak low pressure spreading an easterly flow over southern Ontario. An upper trough supporting this low, spread 25 to 45 knot southwest winds aloft at 3,000 to 5,000 feet.

Part of our approach briefing is to include potential threats. While flying from Copenhagen, Denmark to Toronto I chimed in with, “YYZ’s TAF is forecasting a southwest flow for two hours after this northeast flow. There could be a strong southwest flow aloft.” Silence ensued among the other three pilots and I could hear them thinking, “what is the skipper talking about?” I broke the silence by joking, “my meteorological senses were tingling.” Sure enough ATC mentioned a strong southwest flow aloft with winds shifting to easterly at 1000 to 1500 AGL. The B787 radar was also painting purple wind shear, a rarity.

Buffalo’s upper air sounding clocked the winds southwest 25 to 40 knots at vectoring heights for Toronto. (Buffalo is the closest upper station). When the flow aloft is a strong tailwind, ATC can have a tough time with it. They also want you to get down and slow down. Something very difficult to do in an airliner without significant drag. Luckily, the 787 has “big boards” compared to the Airbus “credit cards” used for speed brakes. The F/O flying this leg couldn’t slow the slippery wing so he disengaged the A/P and rode the glide slope a little high. The well executed maneuver allowed final flap.

I wrote about this very scenario catching a supervisor by surprise some 15 to 16 years ago. It’s mentioned in both weather books. Weather does repeat itself!

The F/O greased it on in a light northeast flow coupled with a wet runway. A wet runway is a pilot’s favourite, but not too wet!

I did mention after we landed about how my meteorological senses were right and that no one buys my books. Hint, hint guys. Even if you have 15, 000 to 20,000 hours, which both my F/O’s had, they could use a refresher.

Shearing Anti-Ice fluid (Type IV) During Takeoff

In North America, most airliners are deiced with orange Type 1 deice fluid that goes on hot, about 60 C to 80 C. It tends to be diluted at various ratios. If it is precipitating, or a pilot thinks precipitation is imminent, an application of Type IV is applied. Type IV goes on cold, undiluted and is designed to shear off during the takeoff run. It does not prevent ice formation when airborne. The airplanes themselves look after airborne icing.

How Buffalo helps with Toronto's forecast

I am back from a long haul flight and Toronto is being inundated with freezing precipitation: FZRA, PL with FZDZ to come. The YYZ METAR below states there is ice on the indicator one millimeter thick (piece of aluminum to replicate an aircraft's skin) and about 2 cm of snow (probably ice pellets) have accumulated. Hundreds of flights have been cancelled. The winds are easterly (ugly wind) and the temperature is -2C with an IFR ceiling.

CYYZ 061800Z 08009KT 2SM -FZRA -PL OVC007 M02/M04 A2995 RMK SC8 1MM ICE ON INDICATOR /S02/

Last evening while flying in from Tel Aviv, Israel during my annual route check, I noticed the temperature on approach to be +3C whereas the surface temperature hovered at -2C. I immediately thought it to be a subsidence inversion as the stratocumulus cloud top was compact and level. However, some middle to high cloud lurked foreshadowing a frontal inversion. I tried to point this inversion out to my flying mates, but I remembered I was getting a route check and below 10,000 feet supposed to be a sterile environment. Oops.

So how does Buffalo, New York aid a Canadian forecaster? For an area with millions of people in the Greater Toronto Area we get our upper air data from the balloon launched twice a day in Buffalo.

Below is the upper air data called a Skew-T Log-P diagram, I wanted to point out the nice frontal inversion associated with a winter warm front. I tried to find a diagram that depicted heights in feet. One can get the data in text, and the above freezing started at 750m (2400 feet) to 2450 (8000 feet). Thick!

Here in Canada we call it a tephigram ) T for temperature and Phi for entropy (thermodynamic entity).

Buffalo’s upper air data for freezing rain/ice pellets in Toronto

Buffalo’s upper air data for freezing rain/ice pellets in Toronto

Southern Ontario’s GFA

Southern Ontario’s GFA

Tis the Season...Fog Season

This article will be appearing in the next edition of Canadian Aviator

Tis the Season…Fog Season

(Foggy IFR, Foggy Flying, The East Coast Veil, Obscurity , Obscure Fog, Advection Fog)

Holding short in the foggiest airport in North America

Holding short in the foggiest airport in North America

Most pilots know there are six types of fog: advection, radiation, upslope, frontal, steam and ice fog. Canada’s East Coast will be entering fog season annoying pilots from early April until well into the summer due to advection fog, but this type can loom anytime of the year if the winds blow in from the ocean.

If you are flying out East during fog season, expect numerous challenges. Airports like St. John’s, N.L (YYT), Halifax, N.S (YHZ), Sydney, N.S (YQY), Yarmouth, N.S (YQI), St John, N.B (YSJ) is where thick fog lurks. Growing up in Halifax, I thought it normal living in a continual thick blanket of fog this time of year. Not until I moved to Ontario did I realize the abundance of VFR.

Advection Fog (also called sea fog) forms when warm moist air advects over a relatively cool surface (water or land). Advection is the movement of air horizontally not to be confused with convection, which is the movement of air vertically. Where the warm waters of the Gulf Stream collide with the cold Labrador Current it’s conducive to forming some of the foggiest places on the planet. Advection fog is not as dependent on wind speed as it is on wind direction. Many claim this fog can lift to a stratus layer under strong surface winds, and indeed this does happen. However, when the cooling is extreme, like over the very chilly waters off Canada's eastern shoreline, think thick fog! You will often find gale-force winds and be unable to see beyond a few feet. The world’s foggiest place is found off the Grand Banks of Newfoundland, where the Gulf Stream and the Labrador Current butt heads. Your career may see you flying supply helicopters to oil rigs located in those waters. And where are the choppers based? At the foggiest airport in Canada, St John’s, of course! In a past article, I mentioned St John’s, a.k.a Torbay, is the windiest, cloudiest, second rainiest, foggiest city with the most freezing precipitation in the country. It goes without saying it has Canada’s lowest VFR ranking, about 65% in the summer lowering to just 62% in the winter.

The two currents behind the making of fog.

The two currents behind the making of fog.

As mentioned, wind direction is a very important factor in the formation of advection fog. For example, advection fog is almost a definite at the Halifax International when the winds are persistent from 070 degrees (true) to 240 degrees. This low lying IFR menace does not form in Halifax when west-to-northerly winds blow.

But don’t think advection fog is strictly an East coast thing. The west coast of Canada and the U.S also gets mired in it. Cold waters hug British Columbia and the States of Washington, Oregon and California and all the way south to the tip of the Baja Peninsula. While Vancouver sees some advection fog, it’s the west coast of Vancouver Island that is the real home to this chilled air mass. Sometimes you’ll see advection fog form over Lake Ontario and move inland to Toronto. Advection fog can be enhanced when a relatively moist air mass overrides a snow-covered terrain. The solid snow may sublimate directly into water vapour, adding to the low-level moisture. This process is conducive to very dense fog.

It takes most of the winter to cool the waters off the East Coast, so “fog season” plagues the Atlantic Provinces for months. The year when I moved back to Halifax as a commuting pilot, the airport authority decided to shut down their two ILS approaches for runway work in July. They had been informed there was minimal chance of fog forming at that time of year. Wrong! I had to book off my first pairing that summer. I couldn't get to Toronto to work my scheduled flight to Paris, France because there were no airplanes! Numerous flights were cancelled.

Advection fog can move well inland and be enhanced by hilly terrain (YHZ is about 15 miles inland on a high point). This type of fog may retreat to the coast during the day as the sun burns it off, but will quickly return as the evening cools. However, a cloud deck may impede the sun from burning off the fog, in which case it will remain until a wind shift causes it to break up. This fog can persist for days and wilt a person’s spirit. If it thickens, drizzle may form, which can cover an extensive area. But no matter its diverse guise, fog is every aviator’s challenge.


My attempt at poetry… 


It prances in diverse guises

It marks its misty presence as it ascends a hill little by little

As a warm wind moves over chilling waters it will form an immense white blanket

It can stay for days and wilt a spirit

Or come and go at the onset of dawn

It may accompany a gale obscuring a pilot’s line of sight to mere feet

It can ally with warm raindrops inducing low visibility

     Or play havoc in bitterly cold Arctic air

It can be a sign of seasonal change as it lunges from warm water

No matter its origin... it will challenge any aviator…

Captain D



Pilots should always be looking at the spread between the temperature and dew point. If the spread is 2°C or less, anticipate FOG!

Fog (FG) is when visibility lowers to less than 5/8 of a statute mile whereas mist (BR) is 5/8 of a mile or more.

BR for mist is derived from the French word Brume.

When flying on the fog-infested East Coast, the answer a pilot usually gives as to when he saw the lights on an ILS approach, is a curt “minimums!” The truth may have had been stretched a bit as to when they actually saw the lights. (ahem)

Urban myth: It’s claimed the Halifax airport location was chosen because it was in a region of reduced fog, but when the trees were cut down to build the airport, fog materialized. My take is any airport near the Atlantic coast, especially one built on the highest terrain in the area, will be conducive to fog. Rather than burning off the fog from the heat of the trees, the clearing allowed the low clouds to reach the surface! St. John’s, Newfoundland suffers from the same plight, as it too is perched upon a hill.




Weather Warm Ups (Inversions)

Just sent another article to Canadian Aviator magazine. Here it is in its “raw” version.

An anvil and a fully developed thunderstorm. This guy hit the tropopause hence the blacksmith looking anvil. I called this inversion or isothermal layer a tropopause inversion. I took a pic of this “bad boy” over Montana. It flirted to FL 460 or so, well above an airliner’s maximum height.

An anvil and a fully developed thunderstorm. This guy hit the tropopause hence the blacksmith looking anvil. I called this inversion or isothermal layer a tropopause inversion. I took a pic of this “bad boy” over Montana. It flirted to FL 460 or so, well above an airliner’s maximum height.

Temperature Warm Ups (Inversions)


A Weather Warm Up (Inversions)


Temperature Warm Ups Aloft

Any pilot knows temperature decreases about 2°C per 1000 feet, but meteorologically inquisitive pilots want to know more about lapse rates and what exactly is going on aloft. I recently gave two talks to local COPA chapters on lapse rates. They discovered weather balloons launched twice a day from over 900 sites globally gather information while ascending to about 100,000 feet where the balloon bursts and tumbles back to earth slowed by a parachute. From these soundings, air is found to sometimes warm with height. These inversions occur in four different scenarios.

Nocturnal inversion. During the night under light winds cooling is more rapid over land than over water. This nocturnal cooling leads to stability in the lower layers as an inversion develops and may lead to the formation of low cloud or fog. Smoke rising in these inversions spreads out horizontally or even sinks as the warm air seeks the cooler air below. Any place with a smoke stack will depict such an inversion, however, unpleasant smells may ensue. I frequently see those low based plumes from pulp mills while flying into Vancouver from the east. Smoke from wood stoves will also form a plume during such an inversion, but the smell is much more pleasant. Nocturnal inversions generally mean smooth flight conditions, but sometimes non-convective low-level wind shear (LLWS) can be present when a surfaced-based inversion results in the development of a low-level jet maximum at the top of the inversion. This inversion decouples the wind just above the surface and allows the winds to accelerate unencumbered by surface friction. Nocturnal inversions can trap many pollutants and moisture, possibly resulting in IFR conditions. If you fly up north during the Arctic winter (think long nocturnal night) you’ll witness dramatic inversions.

Years ago, at a weather conference in Winnipeg, I met a grape grower from the Niagara, Ontario region. His grape-growing operation included hiring a bi-wing aircraft with lots of parasitic drag to churn up the nocturnal inversion, pushing the warmer air to the ground so the grapes would not freeze. Many growers also employ expensive helicopters to do the job. These inversions can also bend ground-based weather radar beams during early morning. The beams are deflected toward the ground giving false returns called anomalous propagation.

Frontal inversion As warm air overrides a cold air mass, a frontal inversion sets up. At the surface during winter below-freezing temperatures exist, but as one ascends, an above-freezing layer develops, on the order of a few hundred feet to several thousand feet thick. Temperatures then decrease to below zero on top of this inversion. Because of this scenario, snow falling through the above-freezing layer turns to rain. The rain then falls into the below-freezing layer near the surface. Depending on how deep or warm this above-freezing layer is, either freezing rain or ice pellets will form which is conducive to serious airframe icing.

Years ago, during a flight from Halifax to Moncton in a Navajo, we encountered light-to-moderate icing in the climb, but an advancing warm front pushed above-freezing temperatures in a thick layer from 4,000 to 8,000 feet with balmy +5° C temperatures. We stayed in this layer until our descent into Moncton and literally watched the ice melt and wash away.

Subsidence inversion Air sinks within a high pressure system, causing air to heat up due to adiabatic compression. This heating eventually causes clouds to dissipate and is why clear skies are associated with a high pressure system.  The sinking (and warming) of the air slows down closer to the surface of the earth, resulting in an inversion in the lowest layer of the atmosphere (typically several thousand feet in height). Clouds may be flattened by this inversion or break up. Stratocumulus is a very common cloud associated with subsidence inversions. Sometimes, this inversion may be so strong that it traps the low-level moisture busting forecasts calling for sunshine!


Often, on descent, I mention the temperature to my flying partner when I suspect a subsidence inversion. I point out that at the cloud top, the temperature will be warmer than the temperature in the cloud. Sure enough, one can watch the temperature sway from, say, plus 6° C at cloud top, to well below freezing a couple of thousand feet inside the cloud. This goes against the standard logic, which says that temperature should increase on descent. The potential for airframe icing exists when the subsidence inversion traps lots of moisture. If you fly near open areas of water such as the Great Lakes during late fall, winter and early spring you may encounter heavy icing conditions in this moisture laden cloud.


The last inversion comes to a surprise for most. Many learn the top of the troposphere (tropopause) has an isothermal layer, but a significant inversion may be present due to warming from ozone in the stratosphere. I am constantly pointing this out to my flying partner (yes, sometimes I get funny looks) and I try to drive it home when teaching new hire pilots who will fly at tropopause heights. The temperature may be -60° C and within minutes it rises to -54°C meaning you flew above the tropopause. On a recent flight from Frankfurt to Calgary at flight level 380 the temperature went from -70°C to -54° C. I haven’t seen such frigid temperatures in a while so I took a picture of the readout. This inversion is why anvils form from thunderstorms.

A frigid outside temperature of MINUS 70 Celsius.

A frigid outside temperature of MINUS 70 Celsius.


There are four types of inversions: nocturnal, frontal, subsidence and one at the tropopause.

Inversions imply stability, but LLWS may occur during a nocturnal inversion.

Warm air aloft and cold air below indicates stable conditions.

Four inversions: subsidence, frontal, nocturnal, and at the tropopause.

Four inversions: subsidence, frontal, nocturnal, and at the tropopause.

Winter warm front and its associated inversion.

Winter warm front and its associated inversion.

Canada and Great Britain plot upper air data on charts called tephigrams, but south of the border they are labelled Skew-T log P diagrams.

You won’t find these plots on NAV CANADA or Environment Canada’s site, however, the university of Manitoba and UQAM (Université du Québec à Montréal) tap into this source.

Many sites and universities supply data from upper air soundings.  

Doug Morris is a B787 captain/certified meteorologist. His weather book, Canadian Aviation Weather, has a great chapter on lapse rates.

Doug recently published an American aviation weather book, Pilot Weather: From Solo to the Airlines.

Nav Canada Update Needed

My previous post depicts what I wrote for my weather column. Below is what made the cut. If you freelance, be prepared to have things changed, altered and mutilated. That’s show biz!

Oh, it looks like I submitted the wrong website address for Pilot Weather. Shoot! It should have been

Pilot Weather is selling like a hot cake. Canadian Aviation Weather needs a boost. Anyone?


Crickets, Warts and Cow Patties

A pending Canadian Aviator article

You probably thought I would be talking about unique weather lore with this title. Sure, male crickets chirp at different rates according to temperature. Found on the web... “to convert cricket chirps to degrees Celsius, count the number of chirps in 25 seconds, divide by 3 and then add 4 to get the temperature.” But “crickets” also denotes silence or NORDO (No Radio) for us pilots. It’s what I experience from my weather blog, feedback from this column and my requests to update NAV CANADA’s weather website.

About six years ago while researching for my weather book, I approached NAV CANADA regarding their archaic weather website. For years, it’s header broadcasted its emergence in 2006 and revision in 2007. But nothing has been touched since. Truth be told, they recently removed the header stating its birth date maybe because some of us were raising eyebrows. Every tab I examine has gaping holes.  “PIREP not available” is found on the PIREP tab for most regions. Have pilots given up? And why can’t I get a high-resolution surface analysis chart? The same one is available on Environment Canada’s site. And why do I have to type in the four-letter ICAO code for METARS and TAFs when the three letter IATA code would suffice since they don’t supply weather outside the Canadian border? The satellite pictures are poor quality, the weather radar does not supply cloud tops in feet and there are more legal disclaimers than there are weather tabs. It’s probably the same reason why Environment Canada persists in calling it ANAL surface for surface analysis. I know many of you gave up and have moved on to other sites/apps, mostly American. We are losing our Canadian meteorological identity. At one time, 9 out of 10 initial conversations began with the topic of weather and that included pilots. Now when an quiet/awkward moment occurs we all reach for our cell phone. But at least we have the TROWAL (Trough of Warm Air Aloft) to reference an occluded front. That is as Canadian as Tim Hortons. Sorry to come out punching with such a negative overtone. To prove I am not all sour and not just another high time crusty ornery captain, my enRoute magazine column will have an upbeat take on pilot hiring - if there ever was a time to become a pilot, the time is now! Okay, back to my stormy take on weather politics.

Over two years ago, I attended an aviation weather conference in Montreal geared for you, the pilot. This three-day seminar consisted of a room filled with meteorologists, dispatchers, academia and one pilot, moi. There I challenged NAV CANADA’s weather liaison why their weather site has not been updated. His lips moved and all I heard was blah, blah, blah. Funny, I could recruit two young computer whizzes on Friday from any Canadian college or university, feed them pizza, beer and legalized Canadian marijuana and they would have a gleaming weather website by Monday morning.

To fly safe, you must challenge and query on a continual basis. Weather and aviation is dynamic so why aren’t you challenging the norm regarding an updated weather website? Are we Canadian aviators that inert? I give the site D+ for disappointing and a disservice.

But it doesn’t stop there. I have been trying to get Transport Canada to acknowledge my weather book, Canadian Aviation Weather, as a viable alternative to a book written over four decades ago, the Air Command Weather Manual a.k.a the ACWM. Don’t get me wrong, this monochromatic book geared for the military is excellent when it comes to theory, but is defunct of aviation forecasts or how to read a METAR. This weather fossil, albeit well written, is pre-internet, smart phone or lap top. Yes, it’s that old and yet the book is the number one seller for aviation meteorology in Canada.

Because my book is not government published the standing policy is Transport Canada can’t/won’t acknowledge it. It is why most flight schools and colleges are reluctant to take it on because their curriculum is geared to questions and material supplied from the historical ACWM. To paraphrase one Transport Canada employee’s take on things and to offer up an explanation why status quo rules, “My grandfather used to say, don’t touch the cow patty, it will only smell worse.” How is that for mandated safety? He admitted to low staffing levels, but claimed my book is being (might be) tagged in their database as a reference for hundreds of exam questions.

I too worked for the federal government and realize the frustration. Over 30 years ago, I was getting an annual “route check” on the weather desk. The supervisor asked what I would like to see or accomplish as a forecaster. I wanted to close the huge gap between weather and the pilot. Sadly, that bridge has never been built nor is it on the drawing board.

My aviation career is slowly unwinding. I teach and write for that young lad in Prince George, British Columbia learning to fly, or for the mother of three changing careers in Quebec City, Quebec flying a Navajo or for that seasoned helicopter pilot flying out of Churchill, Manitoba. After all, the company I fly for also has meteorological warts. They still reference the METAR and TAF as SA (Surface Actual), FT (Terminal Forecast) and FC (a short Terminal Forecast). The system changed 22 years ago, when I was hired! Yes, I’ve been asking. But every large organization has warts. It’s how my friend described his airline that launches from the heat of Dubai, U.A.E. This A380 skipper nailed it with the wart analogy.

To a quote an instructor, pilot, and mentor for young aspiring pilots, “What underlies this malaise and failure to respond to changing conditions and requirements in aviation?

A kick start and wakeup call is in order…”  As an aviator challenge the norm. Take up the quarrel and poke those cow patties.

Doug Morris is a B787 captain, certified meteorologist and wrote Canadian Aviation Weather.  His latest book, Pilot Weather: From Solo to the Airlines is hot off the press catering to pilots south of the border

Time for Weather

Here is the latest found in Canadian Aviator magazine. I called it "Time for Weather" but it was called "When the Ball Drops." Every pilot should make their way to Greenwich to experience where time starts. 

Weather 1.jpg
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