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QFE why?

Old 29th Jun 2001, 02:35
  #21 (permalink)  
Flatus Veteranus
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Q Code goes back to WT days before the war. Dits and Dahs and all that. I think the SOP on Vulcans was QFE on Captains alt. and QNH on Co's.

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presto digitate
 
Old 30th Jun 2001, 17:05
  #22 (permalink)  
RMPA
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I've operated mainly as a military pilot, both in the RAF and with the USN, but lately I've been a civvy. Whilst operating in an aircraft with a limited bang seat performance during and immediately after take-off I suppose it was nice not to have to do a sum when it all turned to s**t, but that sum could easily have been performed prior to the excitement. Since the height of ground is usually referenced to sea level it makes sense to me to use QNH. This is especially true if the RAF are planning to operate aircraft with reasonably modern equipment like EGPWS, where the terrain database is also referenced to QNH. We will make this clever system, which will be fitted to Nimrod MRA4, ASTOR and A400M (and anything else that comes after them), completely useless during the approach. Any long range aircraft operators will be used to using QNH anyway; asking US and many other controllers for QFE will cause more problems than it will cure. How clever is a system that: 1) Is different to everybody (just about) elses. 2) Disables equipment that is designed to protect you. 3) Requires two different pressure settings to be set during the transition to an approach. If we are flexible enough to use QNH when we go abroad or go to civil airfields, how about being flexible enough to allow those Groups within the RAF to use the system that is appropriate to their operations, rather than impose the limitations, largely brought about by fast jet operations, on everybody. If it is not FJ ops, but rather Training Command that has imposed QFE on everybody, then we have a serious case of the tail wagging the dog.
 
Old 30th Jun 2001, 20:24
  #23 (permalink)  
Mmmmnice
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Woah boy geek alert! I'm no statistician but I'm sure someone out there can come up with the proof that more "professional" QNH users have CFIT incidents than out of step military aviators. The real problem comes when some joker decides to change a system that everyone understands; so I guess it's back to QNH apps next week then!
PS. I like QFE but I'm not really paid enough to care that much - coming through ready or not...........
 
Old 30th Jun 2001, 20:38
  #24 (permalink)  
Uncle Ginsters
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Chaps, i think the real question here is " Why do the rest of the aviation world use QNH?" Surely the most important factor in an approach is your height above the TDZ? Obviously in places that would require a huge wind (Nairobi, Calgary etc...) it makes sense to use an alternative, but in this country?

And in answer to the 'Q' question, 'Q' is the scientific denominator for pressure. As stated before, the 'FE' and the 'NH' should really be subscripts and stand for Field Elev. and Nautical Ht. Wish i could help with the others but i've never really heard of any of them,

Smiles,

Unc.

[This message has been edited by Uncle Ginsters (edited 30 June 2001).]
 
Old 1st Jul 2001, 23:25
  #25 (permalink)  
Blue Stuff
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Thanks all for your answers to the 'Q' question. I seem to remember the term from my fluid dynamics ...

Speaking as a relatively baby pilot, it seems much more sensible to read your height relative to the aerodrome on T/O and Ldg. After all, you don't particularly care about anything else in this scenario. If you're low-flying, the RPS is useful, and if you want flight levels, set SPS. A case of horses for courses, is it not? I suppose QNH might come in handy if flying a Catalina ...
 
Old 2nd Jul 2001, 02:55
  #26 (permalink)  
mr hanky
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Sound the geek alert again! Hate to rain on your parade Uncle G, but I think the answer must be something different, given that 'q' only refers to dynamic pressure (.5 x density x speed squared) not atmospherics, and that some of the abbreviations have nothing to do with pressure anyway (eg QDM = runway heading, from what I remember). Any more theories out there?
 
Old 2nd Jul 2001, 03:22
  #27 (permalink)  
Thud_and_Blunder
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Blue Stuff,

No, the Q (and Z) codes were not avation-specific. An instructor of mine in my pre-aviating days gave me a potted version of their W/T origins, and opined that Q and Z were the best with which to begin the trigraphs as they are the longest Morse letters that won't easily be confused (by a tired listener) with numbers. Bear in mind that a lot of codes were sent with quantifying figure-groups immediately afterwards. Most users only needed a small easily-remembered selection of the codes for normal ops - the complete list would've taken up too much room in the average W/T operators workspace.
 
Old 2nd Jul 2001, 03:25
  #28 (permalink)  
Harry Peacock
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Used both systems and personally prefer QFE but no one really worries about my opinion anyway.

One point though cloud base is given relative to the airfield so when calculating alternate requirements etc you've still got to do some mental gymnastics adding this and subtracting that etc. ..... and the approach plates print both heights for minima's anyway!
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QFF is the setting on the sub scale that gives the same reading as a known datum eg. Rad alt reading or A'field reference points.
 
Old 2nd Jul 2001, 07:17
  #29 (permalink)  
Out Of Trim
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Mr Hankey, I believe QDM = Magnetic Heading to Airfield Overhead. QTE = True Bearing from Airfield to the Aircraft. QSY = Change Frequency.. QNH & QFE already adequately explained.. but seem to remember QGH but can't remember quite what that refers to..

[ 09 July 2001: Message edited by: Out Of Trim ]
 
Old 2nd Jul 2001, 09:38
  #30 (permalink)  
Whipping Boy's SATCO
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QGH - Direction finder homing and procedural approach technique. Still in use at the odd airfield.
 
Old 2nd Jul 2001, 09:42
  #31 (permalink)  
Thud_and_Blunder
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I think QGH was a controlled descent through cloud - a DF-based ATC procedure for getting a/c down into the overhead of the r/t aerial when all other means had failed. You could hear the controllers morale hit rock bottom when you requested it...
 
Old 2nd Jul 2001, 11:13
  #32 (permalink)  
G Fourbee
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There was also the flame-out QGH - beautifully introduced by an Acklington controller as "inrease speed, commence spiral left, call Cardinal Puffs with pints!"
 
Old 2nd Jul 2001, 12:36
  #33 (permalink)  
Flatus Veteranus
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You should have heard the Approach Controllers at Driffield and Middleton in the bad old days, when they had to cope with several aircraft on QGH at once - particularly before they got CRDF and had to get the QDMs by squawk-box from a manual homer. We took our hats off to those guys! Incidentally, QTE was the True bearing of the aircraft from the station. "They" would not put ADFs in the Meteor or Vampire because Fighter Command, who laid down the policy, only operated within an elaborate fighter ground environment (unlike MEAF and FEAF). The RAAF Meteors sent to Korea were, I believe, fitted with ADF. If the RAF aircraft had been, quite a few aircraft (and lives) might have been saved.

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presto digitate
 
Old 2nd Jul 2001, 14:13
  #34 (permalink)  
Cahlibahn
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There are hundreds of the buggers! (Q codes, I mean)

See
http://massis.lcs.mit.edu/telecom-ar...utical.signals

 
Old 2nd Jul 2001, 21:18
  #35 (permalink)  
Gash Handlin
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Thumbs up

And if you were an RAF Newton controller you would do three/four QGH's an hour as the trips came back on a 8/8 day as there wasn't a radar, thanks guys it was an amazing confidence booster doing a practice IF approach and having a look out the window to see you're being turned in exactly the right place when the only aids in the tower are DF and a stopwatch.
 
Old 2nd Jul 2001, 21:50
  #36 (permalink)  
N Genfire
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QSY ?

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Not if I can do it tomorrow.........
 
Old 3rd Jul 2001, 01:36
  #37 (permalink)  
BEagle
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Wink

There was, of course, the trick of arranging with 2 or 3 other mates a little jape to confuse the QGH controller. The team went to pre-arranged positions about 20 miles from the aerodrome all of which were equally spaced around the points of the compass. After the warning double-key on the frequency was given, they would transmit in sequence: 'True'..'Bearing'..'True'..'Bearing'..'True'..'Bearing'..'Cr anwell'..'Homer'..'Request'..'True'..'Bearing'; each pilot only transmitting when it was his turn!The 'wiggly worm' would dart around the CRT and ATC would go nuts!

Or orbiting that mast down near Melton Mowbray when the 'welease Wodewick' contwoller was on shift and asking for a Twue Bearwing....the answer was 'Two two two degwees Twue'!!

Rotten little $ods, U/T pilots!!
 
Old 3rd Jul 2001, 03:42
  #38 (permalink)  
pana
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To N Ginefire:
Army can have aviation, but do they have pilots?
 

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