Happy New Year everyone! Here is a couple of pages on inversions found in the latest Canadian Aviator magazine.
Affirmative: An aviator’s yes. “Negative” is no. “Roger” is message understood or message received and “Wilco” means will comply.
AIF (Airport Improvement Fees): Supposed to be used solely for the betterment of the airport. But it sure is a bone of contention with most passengers.
Air Crew or flight crew. Crew is also referred to as cabin crew or flight deck crew. Each airline has their own take on this which is why it gets confusing.
Air pocket: A colloquial term coined for an area of turbulence. “Pockets” in the atmosphere do not exist per se, but the term is frequently used with air traffic control, pilots and passengers.
Altimeter: Instrument that indicates altitude of an aircraft usually above sea level. There is also a radio altimeter that measures height above ground at low levels on approach.
Anti-ice fluid: Fluid that prevents ice and snow accretion and designed to shear away during the takeoff roll. It tends to be bright neon green at most airports.
APU (Auxiliary Power Unit): Literally a small jet engine fixed in the tail of the aircraft capable of supplying air conditioning and electricity on the ground. It can also supply electricity during flight. It’s that hissing sound you hear when boarding or disembarking. And yes, it shares the same name of the character seen in the Simpson’s sitcom.
Area of weather: This denotes an area of inclement weather or area of concern. It may be thunderstorms, heavy showers, an area of confirmed or forecast turbulence i.e. fasten your seat belt. As in, “Ladies and gentlemen, we are approaching an area of weather. Please return to your seats and fasten your seatbelts.” If it escalates or is thought to be in the moderate or heavier range, the captain will have the flight attendants secure the cabin and “strap in” as well.
“Arm and cross check” or “doors to arrival and cross check:” The lead flight attendant will make a cabin announcement to remind the other flight attendants to either confirm the doors are armed during pushback or disarmed (deactivate the chutes) approaching the gate.
ASL (Above Sea Level): Also, known as MSL (Mean Sea Level). Altitude of any object relative to the average sea level datum.
ATC (Air Traffic Control): This covers the entire infrastructure, not just the guy in the tower as depicted by Hollywood handling everything from Tom Cruise’s “low and overs” to assigning holding patterns to aircraft 100 miles upwind. There are control centers, ground controllers, ramp (apron) controllers and clearance delivery controllers. Pilots will make cabin announcements using the acronym ATC assuming passengers know the lingo.
Autoland: Most airliners have autoland capability whereby the aircraft lands itself. It is generally used in low visibilities. In fact, it must be used in very low visibility. The airplane, pilot and landing runway must all be certified to conduct an autoland. There are no auto-takeoffs.
Belly: The bottom of the airplane where your luggage is stored. Animals are stored in the belly as well, but tend to be in the aft section and sometimes you will hear their concerns.
“Bottle to throttle:” A term used to depict the hours a pilot must abstain from drinking to be legal to fly. Generally, it’s “12 hours from bottle to throttle.”
Bulkhead. A dividing wall or curtain to separate sections or classes in an aircraft. Some like the extra legroom a bulkhead usually entails, but the cons are: no under seat stowage, tray table is in the armrest, and on long haul flights, it’s where the bassinets are hung for babies. Don’t be putting your feet on the bulkhead because flight attendants will curtly ask, “do you do that at home?” It’s not classy especially when people take off their socks.
Bumped: This means that the number of seats on the flight have been oversold. Sometimes a passenger may be lucky and get “bumped” up to business class but it usually means you will be put on the next available flight. Checking in early avoids this situation. Some may volunteer to be bumped and the rewards are high and even negotiated.
Cabin crew: Flight attendants designated as the operating flight attendants.
Captain, first officer, cruise pilot and relief pilot: The captain is the commander (supreme being) with four stripes on their epaulets and tunic sleeves with a bit more embroidery on their hats. Media incorrectly denotes the captain as the “pilot.” The first officer is second in command with three stripes, but many reference the passé term, co-pilot. The cruise pilot replaces the captain or first officer for crew rest reasons and does not land or take off. The augment pilot is usually a qualified first officer and flies when four pilots are required in long haul flights. Many airlines designate some flight attendants with stripes, maybe one or two, and even maintenance personnel is getting striped shoulders.
“Cargo doors are closed up:” This is a good sign indicating push back from the gate is imminent. There are light indicators in the flight deck telling the pilots of the status of the cargo doors. Something we watch closely as departure time nears.
Chop: Rhythmic or more consistent intensity and frequency of turbulence. Equivalent to riding a bicycle on a cobble stone road or riding on the subway or train. Chop is lessor of concern than turbulence. It is referenced by pilots about 70% to 80% of the time. It has either light or moderate intensity. There is no severe chop.
Clear, few, scattered, broken, and overcast: How cloud amounts are depicted using the fraction of 1/8s (oktas). Clear (0/8), few (1/8 to 2/8), scattered (3/8 to 4/8), broken (5/8 to 7/8) and overcast (8/8). And don’t worry, “broken cloud” is not a dangerous entity like one of my passengers thought.
Cockpit: Now becoming more and more politically incorrect. See Flight Deck.
Commuter: Many airline employees do not live in the domicile they work. About 30% to 50% of pilots commute. Less so for flight attendants. You will see them nestling next to you on a flight either dressed in uniform or travelling incognito.
Cons (abbreviation for contingents and not an abbreviation for convicts): A contingent passenger is likely an airline employee travelling on a standby, non-revenue ticket. The “contingent” term refers to the passenger’s status as being contingent if all revenue and senior standby ticket holders have been accommodated. “Stand-bye” is also used.
Contrails (COTRA) Condensation or vapor trails: No NOT chemtrails! Moisture from the engine exhaust freeze causing ice laden trails. If they disperse very quickly the air is dry, if they take tens of minutes to disperse it indicates moisture aloft thus weather maybe nearby.
Crash pads: What pilots and flight attendants call their temporary sleeping arrangements (their home away from home) when they commute. Prices vary depending on how many reside in these “unique abodes” with many outfitted with bunk beds. There certainly are different star ratings when it comes to crash pads.
Crew member: Person assigned to duty in an aircraft.
Cross bleed engine start: Most airliners use compressed air from the APU (Auxiliary Power Unit) to start the engines. If the APU is not working then a cross bleed engine start means an engine is started at the gate using portable external air and then the second engine is started from cross bleeding air. It ups the pilot’s load factor and is not what they want to see when showing up for work. The Dreamliner I fly uses batteries to start the engines and we can start both at the same time.
Crosswinds: Takeoffs and landings are generally performed into the wind for maximum performance. But wind frequently blows across the runway demanding crosswind landing and takeoff techniques.
CVR/FDR/Black Box: These terms frequently make the news. CVR (Cockpit Voice Recorder), FDR (Flight Data Recorder) and the infamous black box (which isn’t black but bright orange or red) is either the CVR or DFR.
Deadhead: Either a pilot or flight attendant repositioning to another airport as part of their duty. Crew may either deadhead in their uniform or in “civies.”
Deicing: Removal of ice, snow, and frost accumulation on an aircraft’s surface. It’s the law to have these contaminants removed before takeoff. There are a few exceptions.
Direct flight: Please don’t get this confused with non-stop flight. It often is. Direct flight means you are heading in the same basic direction but it MAY mean one or several stops along the way. Think possible “milk run.”
Domestic flights: It generally means flights within the same country, however, when a pilot says they are a “domestic” pilot it may mean they fly within North America i.e. they don’t fly internationally. There are domestic airports and international airports.
“Doors to arrival and cross check.” (I repeated this one) Another cabin announcement made by the “boss” flight attendant to their peers to confirm the doors are disarmed. Opening a door from the inside when armed means “blowing the chute.” Not only is it dangerous, but it undeniably means a delay or cancellation. Yes, I’ve seen a blown chute, but only once in my career. When doors are opened from the outside the chutes are automatically disarmed. I still get the heebie-jeebies if I have to open a cabin door.
Equipment: Another name for airplane. Airline pilots can only fly the same equipment (airplane) but flight attendants can fly various types of equipment. Pilots now and again have equipment bids to select their airplane choice.
ETA (Estimated Time of Arrival): You will hear that a lot in our announcements. But is it the ETA for touch down or at the gate? Debatable. I give it as the “touch down” time because that is when passengers look at their watches to decide whether they have to bamboozle it. I figure people add about 10 minutes of taxi time for large airports and five minutes or less for small less busy airports. Ambiguity is everywhere.
FAA/TC: The Federal Aviation Authority and Transport Canada are pilot friends. Ahem.
Just like that nice police officer is your friend as you receive a speeding ticket. But seriously, they set the goalposts as to the rules and regulations we abide by. Reminds me of an overused aviation meme, “Hi, I am from the FAA and I am here to help you.”
Fear of Flying aka Aerophobia: An anxiety disorder involving the sense of fear and panic some passengers experience when they fly or anticipate flying. It can be alleviated or treated by reading books like this, taking courses or seeking professional help.
FIN or FIN number: This number is used by airlines to differentiate their fleet. The true acronym is illusive. Maybe Fuselage Identification Number, or Fleet Identification Number or the number inscribed on the vertical tail called the fin? When a pilot calls maintenance, they address themselves using the FIN number, maintenance is not concerned about the flight number. FIN number is not to be confused with the aircraft registration which is an alphanumeric code like that of car license plate. Aircraft registration starts with a “N” in the USA and “C” in Canada.
First class and business class: Many get this confused and think the seats in the front of the aircraft are deemed first class. Truth be told there is no North American carriers with first class cabins. Yes, international carriers flying into North America such as Emirates, Etihad, Singapore, Lufthansa and Air France have first class.
Flight attendant NOT stewardess or steward: Saying “stewardess” instead of flight attendant reflects how little you travel or how old you are. Be cool, start flying and delete stewardess from your vocabulary.
“Flight attendants take positions for takeoff”: Or some form of this announcement indicates takeoff is imminent and everyone should be seated.
Flight crew: Crew members designated as the operating crew.
Flight deck NOT cockpit: Cockpit is waning like the term stewardess. Show people you are in the know by shying away from the term cockpit. The flight deck is a pilot’s office with a great view especially from the left seat. J
Flight level: Cruising level can also be used to denote the cruising altitude. Flight levels in North America start at 18,000 feet. A small Cessna would never get to flight level heights. Flight levels are predicated on setting the altimeter to a standard value. In the Caribbean, Europe and most places around the world flight levels start at unique altitudes. In Cuba, flight level starts at 4000 feet.
Galley: Means kitchen in an aircraft and stems from the naval term. Stay out of the galley when meal service is happening. It’s an easy to way to annoy flight attendants by trying to chat them up.
Gate agent aka ticket agent: Ticket agent is weening a little too. The ones at the gate are gate agents or CSAs (Customer Service Agents). I know, I married one.
George. During the initial development days of a crude autopilot led by Lawrence Speery a colloquialism for the seemingly magical, invisible copilot emerged. To this day, the term “George” or “George is flying” unofficially represents the autopilot system. There are two Georges on most airliners.
Go around or missed approach: Sometimes a landing can’t be carried out. Either an aircraft has not exited fast enough, weather is an issue or the pilots were not set up to continue the approach so a go around or missed approach is performed. Yes, they can be abrupt with some considering them aggressive maneuvers as the power advances. But it’s safe.
Great circle. One would think a straight line is the shortest distance between two cities but “as a crow flies” is not the shortest when talking flights over the globe. That is why your fight from London, England back to New York would fly over the southern tip of Greenland.
“Grease it on”: All pilots want smooth landings. There is nothing better for the self-esteem. If you want to stroke a pilot’s ego, just tell them they really “greased it on.”
Ground stop/ground hold or ground stop/gate hold: These are all delays. It’s part of the traffic flow program. A ground delay is aircraft delayed at their departure airport in order to manage demand and capacity at their arrival airport. Flights are assigned departure times and you may find airplanes sitting at a conspicuous spot ¾ maybe with the engines shut down to save fuel. A ground stop is a procedure requiring aircraft that meet specific criteria to remain on the ground. It may be airport specific, related to a geographical area, or equipment related. A gate hold is when ATC will not grant a push back clearance due usually to congestion. I’ve sat at the gate (stand) in London, England for 50 minutes waiting our turn.
Headwinds: Winds blowing onto the nose of the aircraft. In North American latitudes, winds generally blow from the west so a westbound flight would encounter a headwind. Flight planners factor this in when building schedules.
Heavy Showers: This could be code for “thunderstorms” or it may mean heavy showers. Thunderstorm implies very nasty weather so many airlines tone it down as far as usage.
High cloud: Classification of cloud with bases starting at 20,000 feet. Many pilots will report high cloud in their announcements not knowing about 2% of the passengers would know or care what a high cloud is.
Holding pattern: A racetrack-shaped course flown during weather or traffic delays. They tend to be turns to the right, but not always. For modern airliners, it is just a push of a couple of buttons to set up a hold. But during ab initio pilot training, a student pilot must determine how to enter the hold and which way to turn. It was one of the more difficult things to nail down during a flight test. Been there!
“How’s the ride?”: What pilots ask to ATC or on common frequencies checking on flight conditions. It drives air traffic controllers nuts, as many pilots as soon as they check in say, “it’s smooth” and in the same breath ask “how’s the ride?” I can hear/feel ATC cringing.
In-charge (I/C) or FSD (Flight Service Director) or lead flight attendant. Maybe even “Queen bee?”: The flight attendant in charge of the operating flight.
IATA (International Air Transport Association): It consists of about 290 airlines supporting aviation with global standards for safety, security, efficiency and sustainability. The three-letter code for every airport (what you see on your ticket or bag tag) is an IATA code.
ICAO (International Civil Aviation Organization): A United Nations agency managing the administration and governance of the International Civil Aviation. Headquarters is in Montreal, Quebec. ICAO codes for airports are four letters and can be far-fetched as to their derivative. For example, BDA is the IATA code for Bermuda (makes sense) but how do you get TXKF for the ICAO code? Yes, it can be explained.
ILS (Instrument Landing System): Consists of the localizer and glideslope providing horizontal and vertical guidance for precision approaches. Most large airports offer ILS capability and it’s a pilot’s preferred approach.
In range checks: These checks are instigated at about 10,000 feet meaning about 10 minutes to landing. You may hear a double or triple chime indicating to the flight attendants to secure the cabin for landing.
Jet lag (circadian dysrhythmia): A physiological condition which results from alterations to the body's circadian rhythm caused by rapid long-distance trans-meridian (east–west or west–east) travel. Generally, you don’t get jet lag flying in a north-south direction. NASA avers for each time zone traversed a day is required to recover.
Jet stream: A narrow meandering fast current of air normally found at higher heights discovered in WWII during high altitude bombing missions. The U.S, Britain and most of the world state jet streams must be at least 80 knots. Environment Canada stipulates winds shall be 60 knots or more.
Jetway (bridge): The bulky, boxlike tunnel used to connect the gate entrance to the door of the plane. Few jetways around the world have windows. Pity. This jerky moving wheeled contraption is the thing that breaks down after wanting out from a 10-hour flight.
By the way, it is the airport authority that own and fix them not the airlines. Most also supply conditioned air and power. The conditioned air can be debatable at times.
Jumpseat: An extra seat (sometimes foldable) in the flight deck for a supervisory pilot, government flight checker, training pilot or for a contingent airline employee. Some larger aircraft have two jumpseats.
Jumbo jet: A reserved usage for the four-engine mammoth B747. There are no longer any B747s flying for North American airlines. The term jumbo never really stuck for the Airbus A380. Most airport signs use a four-engine symbol. Funny, all North American carriers fly only two engine jets.
Knot: How pilots and the aviation world measure speed. It is a nautical (6076) mile per hour not to be confused with a statute mile (5280 feet). Pilots may brag about their airspeed during a P.A. A pilot may convert their 500 knot groundspeed to km/hr by doubling the value i.e. 1000 km/hr (really it is 926 kilometers per hour).
Lavatory: Airplane’s name for the washroom/toilet. Remember there are smoke detectors capable of knowing when you light up. Funny, at one time there were smoking sections on an aircraft, but now if you light up, the airline’s sense of humor has disappeared.
Livery: Fancy name for paint job or design. Many have their opinion on aircraft livery and they will tell you.
Logbook: Every aircraft must have its own logbook which records flight legs. There is also a cabin logbook a head flight attendant fills out for unserviceable equipment. Like the seat you had that wouldn’t recline.
Long haul flight – a flight of considerable distance and time – often with passengers suffering some significant jet-lag along the way. Long haul is about 10 to 13 hours. Ultra-long haul is 13 hours or more.
Mach: Created by Austrian physicists Ernest Mach. Pronounced “mock.” He divided the aircraft’s speed by the speed of sound. Narrow body aircraft fly at Mach .74 to Mach .80 whereas wide bodies fly at .80 to .88.
MEL (Minimum Equipment List). It is a heavy book found in the flight deck whereby maintenance or pilots consult to determine the serviceability of the aircraft due to a “snag.”
Minimum connecting time – the smallest amount of time allowed to change planes at an airport. If these conditions are breached it is known as an illegal connection.
Mist: A more subdued term for fog.
Nautical mile: 6,076 feet. Used in wind and aircraft speeds and distance in aviation.
No-shows – the term relating to passengers who either arrive late or do not arrive at all to travel on their booked flight. Gate agents are known to check the nearest bar for “no shows.”
Non-stop. This is the flight to be on instead of a “direct flight” as it may mean one or more stops along the way.
Non-Revenue: Passenger flying free of charge (not really free), on a standby basis, by presenting an airline/aviation employee pass. Non-revenue passengers may or may not be on duty, therefore this expression also applies to repositioning crew members. Also known as Non-Rev for short.
On call: A period of time during which a reserve pilot or flight attendant may be assigned a flight.
PIL: Passenger Identification List. “Are you on the PIL?” is NOT a personal question.
Pointy end: It alludes to the front of the airplane. It many reference J (business) class or first class or even the flight deck.
Pre/Post 911: The Julian calendar includes BC and AD. In aviation, many policies and security issues adhere to the Pre and Post 911 dates.
Pushback: The process of moving an aircraft backwards from the gate accomplished by coordination between the pilots and ground maintenance crew.
Ramp, apron and tarmac: Essentially the same thing but the media likes coining it the tarmac. But they also use tarmac for the taxiway and sometimes the runway.
Rampie: Name for ground handling agent. You may also hear “ramp rat” tossed about.
Red alert: A Canadian airport warning when thunderstorms are within three statute miles of the airport. Outside, terminal strobe lights may also ensue.
Red-eye: A flight that departs late at night from the west and arrives early in the morning, usually after 9 p.m. and arriving by 5 or 6 in the morning. The actual “red eye” stems from being up all night.
Reverse thrust: The temporary diversion of an aircraft engine's thrust so that it is directed forward, rather than backward. This aids in slowing the aircraft upon landing. If possible, many airlines use reverse thrust sparingly to reduce wear and tear of the engines. Hence many passengers associate a nice landing when they don’t hear or feel the loud rumbling caused by reverse thrust.
Seat belt extension. An addition to the regular seat belt for the more rotund passenger. They are getting used more and more.
Seniority: A numerical ranking system based on date of hire used by the airlines to determine positions, vacation, domiciles, monthly flights and more. It is the pecking order for anyone’s aviation career. Some airlines try to use a more fairer approach like status pay, but the seniority system rules in North America.
Simulator: Where pilots learn to fly their aircraft, and stay current on their aircraft type. They are multimillion dollar marvels propped up on spindly hydraulic jacks capable of replicating about 500 scenarios/emergencies. You may hear it referred to as “the box,” or the “sin bin.”
Slam Clicker: A member of the flight crew that heads directly to their hotel room, slams the door and clicks the lock. They usually stay there until crew pick up or don’t socialize if they wonder from the room.
Snag: An item that will need immediate or eventual fixing. Many things on an airplane do not have to be fixed right away if they adhere to the guidelines found in the MEL (Minimum Equipment List) such as a reading light, leaky water facet or clogged drain. But the paperwork may cause a delay.
Stand. Another name for gate. I haven’t heard it used in North America.
Standby: A passenger holds a ticket but sometimes does not automatically guarantee a reserved seat means instead that they are waiting for availability. A standby passenger may also refer to a non-revenue (contingent) passenger or employee. Sometimes, they “stand” there and wave “bye” to the airplane.
Static wicks. Stick like devices found on the trailing edges of wings, flaps, tail, etc to dissipate static build up.
Stopover – an overnight stay (or possibly longer) at a location en route to your final destination. This is usually done to break up a very long journey for example London to Los Angeles with a stopover in New York.
Tail Spotter: An airplane geek fascinated with aircraft/aviation. Almost every airport has them usually found along the perimeter of the airport premises. Many are avid photographers and some travel the world to capture airplane photos.
Tailwind: Wind in the same direction as the motion of the aircraft.
TCAS: Traffic Collision Avoidance System. A system which interrogates other aircraft and determines if a conflict is imminent. If so, it will dictate specific instructions.
“Thanks for your patience”: An overused and very assuming phrase as in “we will be pushing back 30 minutes late because of the late arriving aircraft. Thanks for your patience.”
“Top of drop”: Means time of descent. Pilots will give flight attendants a “top of drop” time according to the flight management system’s calculations.
Transcon: Transcontinental flights either from the west coast to the east or vice versa.
TSA (Transportation Security Administration): A post 911 agency having the authority over security of the travelling public and flight crew.
Turn: As in, “I am doing a turn today” meaning a flight attendant or pilot will be flying back on the return flight the same shift. It is deemed productive flying meaning they accumulate many hours in a short time. I am shocked some passengers think aircrew do turns after a 8 to 12 hour flight. Think about it.
U/S: Unserviceable. “Ladies and gentlemen, it is hot in the cabin because the APU is U/S.” Translation: the auxiliary power unit that supplies cool air is not working.
Unruly Passenger: A disruptive passenger. There are four levels and airlines take it very serious.
Vortices (wake turbulence): Aircraft wing tips induce swirling air that can cause an abrupt bump to another aircraft like a boat encountering waves from another boat’s wake.
Wheels up time: A ground delay or part of the flow control program which dictates a flight to be airborne at a certain time.
Wide body and narrow body: No, it doesn’t refer to the size of the pilot or flight attendant. (But it’s been known for pilots or flight attendants to “gain a few” when they regularly fly overseas). A wide body aircraft has two aisles whereas narrow bodies have one aisle.
Winglets: Sleek devices to increase efficiency by reducing drag at the wingtips. Some aircraft have unique winglets especially the newer B737s with a dual feather design.
Zulu, GMT (Greenwich Mean time), and UTC (Universal Coordinated Time): Z for Zulu originating from the military is the name of the international time zone based in Greenwich, England whereby all aviators refer to. Greenwich Mean Time is passé but still frequently used and it’s not UCT for Universal Coordinated Time but UTC. Aviation is unique.
This is what I wrote for January 2019 edition. Not sure why they used so many stripes on the epaulettes but it is still a great graphic.
You are probably asking what a recent marine catastrophe in the Caribbean has to do with aviation weather. Well, I think a lot! A doctor friend, and huge aviation enthusiast, lent me his copy of Into the Raging Sea and it sure captivates the reader. As a meteorologist, commander of an airliner, son of a mariner, and so-so intermediate sailor, it captivated me.
It is based on the sinking of El Faro, a U.S registered roll-on/roll-off/container ship that went head on with a ferocious category three/four hurricane, Joaquin. Many would think this happened decades ago, but the ship plummeted to the ocean floor October 1, 2015. How can that be with accurate weather forecasts and super-fast weather dissemination? How could a sane captain steer right into the claws of this meteorological monster?
The author, Rachel Slade, did a great job researching. As with any accident there are multiple reasons. We pilots are taught the “Swiss cheese model” and learn when the holes of the cheese line up, accidents/disaster ensue. However, the author sided with most non-weather types, and challenged the accuracy of the forecasters. It's so easy. But this was a bloody huge hurricane, so why did everyone get hung up as to where precisely it’s twisting centre lay? It is like a pilot flying into a thunderstorm simply because it’s forecast location was a tad off.
This book is also about CRM (Crew Resource Management) or the lack of. CRM is infiltrating the medical field where surgeons operate with checklists and realize they are not an almighty being. I know of pilots working part time to spread the word of team work in the medical profession. Looks like the marine world needs help as well.
One line from Slade on page 50 quotes a MIT professor dedicated to weather and its understanding, “If the definition of wisdom is understanding the depths of your ignorance, meteorologists are wise.” Looks like I am blessed. LOL
Again, this book is a great read. Of course, Canadian Aviation Weather has a great chapter dedicated to hurricanes.
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.
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.
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. www.canadianaviationweather.ca.
Doug recently published an American aviation weather book, Pilot Weather: From Solo to the Airlines. www.pilotweatherbook.com
I managed to sneak in a weather topic for my enRoute column. I love the graphic.
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 www.pilotweatherbook.com
Pilot Weather is selling like a hot cake. Canadian Aviation Weather needs a boost. Anyone?
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. www.canadianaviationweather.ca. His latest book, Pilot Weather: From Solo to the Airlines is hot off the press catering to pilots south of the border www.pilotweatherbook.com.
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.
Coming soon...an aviation weather book for American pilots...Pilot Weather: From Solo to the Airlines. ETA is September 2018. This book will include a glossary of over 550 entries and will be in full colour (Oops, I meant color for my friends south of the border). I have hit a meteorological wall trying to convince Canadian pilots that Canadian Aviation Weather is the best weather book out there, so it's time to move south of the border. "Trumpland" here we come!
Over Great Slave Lake (North West Territories) in a DC-3 during microbursts.
A former student Jamie MK from the Brampton Flight Centre is building time with Buffalo Airways (think the iconic show Ice Pilots) in a DC-3. Notice the outflow cloud and the wave of water created by the intense downpour. Can you imagine trying to land with this parked over an airport? Or worse yet, training to land a float plane near the dramatic walls of water.
Looks like my column made it to a two page spread instead of 1.5 pages sharing space with an ad. Unfortunately, the pictures still don't get captions, but I will take the upgrade.
Thule's white runways
On page 5 of Canada's best written weather book for pilots (ahem), it is mentioned, "the asphalt runways in Thule, Greenland are painted white to enhance albedo and prevent heating of the permafrost beneath the surface." The topic of unique airports came up while flying over Greenland after we almost diverted to Moscow on a recent New Delhi to Toronto flight. My F/O air dropped this pic to me. (It turns out this same pic is on the internet). When looking at the Jeppesen approach charts there is no mention of the runways being white. Something a pilot should know when breaking out from an ILS approach and seeing a white runway. Think slippery.
Thule is so far north, the runway headings are in True. It's just short of 10,000 feet long.
Just thinking out loud as far as a cover design for a new weather book aimed at our friends south of the border. The completion has been painfully slow. But with the addition of an additional graphic artist there is light at the end of the tunnel. Still hoping for an early summer closure.
In the latest edition of Canadian Aviator, I discuss how METARS around the world are not created equal. A METAR is the largest staple for any pilot's weather briefing, but many pilots are shocked to learn they actually differ around the world. This article will broaden your METAR horizon. Of course, I included an in-depth chapter in my book as well.
Got to write on clouds....
This edition talked about weather across Canada. Some of the pics got sized disporportionatley so here is the graph I wanted to convey.
If a pilot starts making reference to how clouds look, then an eyebrow should be raised. If you hear, "hey, that cloud looks like a bunny rabbit" then suspect an hypoxic state from oxygen deprivation and tell he or she to "go on oxygen!"
But how do you respond when a pilot says, "hey, that cloud over there looks like a big (ahem)!"
F/O Brent was excited to fly with me (no, not that kind of excited). He knew I was a meteorologist and wanted to share a couple of pics he took over Colorado. Most have heard of cloud seeding using silver iodide to suppress the development of a thunderstorm. Maybe viagra was used instead for this cloud?
Even though I can't claim ownership to the pics, I will stake it's nomenclature, Ce (Cumulus erectus). This "unique cloud" is actaully caused from the extreme late stages of a dissipating cumulonimbus. (Seriously).
Canadian Aviation Weather (Book)