Help decoding ATC chat

[Albert Tatlock]

Return to LHR on a united 777, was listening to their "from the cockpit" audio channel. ATC asks for confirmation that plane is 777 Golf. Later on, hear BA flight say he's a 777 Foxtrot. What's the significance of the F and G?

And what's the smallest 'heavy'

Ta

[TightSlot]

At a guess - each flight was confirming to the controller that he/she had already listened to the latest updated ATIS (http://en.wikipedia.org/wiki/Automatic_Terminal_Information_Service) information.

This is not really my aisle, so I stand to be corrected, but that would be a sort of educated guess.

[EastMids]

Airfield information on that ATIS (Automatic Terminal Information Service) broadcast on a radio frequency is letter coded to ensure that the current set of information is being used.

ATIS will go something like this "London Heathrow Information Golf: Landing runway 27L, wind 230 degrees 15 knots, visibility 5000 meters, few [cloud] 2000 feet, temperature +7, dewpoint +5, QNH (pressure) 1015..." When the details change, the letter is updated to the next one alphabetically. Passengers listening to channel 9 on United don't usually hear the ATIS, because the flight deck crew get it on another (secondary) radio.

In the above example, pilots may be asked to confirm they have "information golf" (G) - effectively they are being asked to confirm that they have the latest airfield/weather information. If the pilot says he has received foxtrot (F), he has received the previous report not the current one.

Andy

PS: Heavies - heavies are usually just the widebodies (can't remember the exact conditions for "heavy"), but 757 can be designated heavy as it produces more wake turbulence than many other narrow bodies

[Back at NH]

Heavy = Maximum Certificated Take Off Mass of 136,000kg or greater.

[PAXboy]

Albert TatlockAnd what's the smallest 'heavy'If I recall correctly, the smallest was Concorde of late lamented life ... :sad:

Welcome aboard Albert.

[Final 3 Greens]

Paxboy

Concorde was not 'small', she was 213' in length.

But she was very slim ;)

[Final 3 Greens]

Once allegedly heard on Southend Tower frequency....

Light aircraft "Southend, G-ABCD request joining information"

Tower "G-ABCD, do you have Hotel?"

Light aircraft "Southend, negative, I'm kipping with my mates."

Allegedly.

[Northbeach]

Albert,

A pilot flying into an airport needs to know certain information like wind direction and what runway is in use as well as several other items. When you have just a few flights a day it is a simple thing for the tower controller to give the pilot(s) this information. However, if you have several hundred flights a day then it would become terribly cumbersom.

There is a dedicated frequency that gives the pilot(s) that information it is called the ATIS (Automatic Terminal Information Service). The information is updated hourly, and as necessary as significant changes take place.

When the pilot checks in with the approach controller he/she gives the flight number/aircraft number and the single letter designator of the ATIS information they have: A (alpha), B (bravo), C (charlie)-whatever. This communicates to the approach controller that this flight is aware of the current conditions and runway(s) in use.

Welcome to PPrune.

[Sgt.Slabber]

Albert,

I believe this may be what you are after:

When providing aircraft type on a flight plan, pilots/operators are required to include information about the on-board, certified equipment using an identifier code as a suffix to the equipment type. For example, "B739/J" means a Boeing 737-900 with "Flight Management System (FMS) with DME/DME and IRU position updating and RVSM." ATC sometimes request confirmation of the eqiupment fit code.

A full list of codes is available here:

FlightAware > FAQs > Aircraft Equipment Suffixes (http://flightaware.com/about/faq_aircraft_flight_plan_suffix.rvt)

[boredcounter]

Was small, heavy in the US, but perfectly formed all over the world..........Better than BUFF flying from and to our airports!

[Engine overtemp]

Sgt. Slabber says ATC sometimes request confirmation of the equipment fit code.


Maybe I've been lucky but in quarter of a century of commercial flying I've never heard such a request!

[HEATHROW DIRECTOR]

ATC is not really concerned with equipment fit - I never had any experience of such requests in a lifetime in ATC.

The simple answer to the original query has already been given several times - the arrival information code letter. ATC needs confirmation of the aircraft type too because airlines have a habit of changing aircraft and it can have significant consequences for wake turbulence spacing.