Go Back  PPRuNe Forums > Aircrew Forums > Military Aviation
Reload this Page >

What Does High Key mean when in the circuit?

Wikiposts
Search
Military Aviation A forum for the professionals who fly military hardware. Also for the backroom boys and girls who support the flying and maintain the equipment, and without whom nothing would ever leave the ground. All armies, navies and air forces of the world equally welcome here.

What Does High Key mean when in the circuit?

Thread Tools
 
Search this Thread
 
Old 19th Feb 2018, 08:54
  #1 (permalink)  
Thread Starter
 
Join Date: Feb 2018
Location: Lincolnshire
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
Question What Does High Key mean when in the circuit?

Morning All

I have often heard the term High Key when an aircraft is in the Circuit. What does this mean.

Cheers

Glider 90
GLIDER 90 is offline  
Old 19th Feb 2018, 09:06
  #2 (permalink)  
 
Join Date: Jul 2003
Location: Near the coast
Posts: 2,371
Received 553 Likes on 151 Posts
High key

I realise the use of it may vary slightly from type to type but generally it is a term used when doing a PFL pattern. It is roughly equivalent to the downwind call (low key or final key may be used for the finals call). The orientation may differ between aircraft but it is designed to allow a constant glide angle to be maintained from overhead the runway until touchdown.

I’m sure others can provide more detail for specific aircraft types. I can only speak for the Hawk. Our High Key (for a circling PFL) is 90 degrees off at the upwind threshold.

BV
Bob Viking is offline  
Old 19th Feb 2018, 09:09
  #3 (permalink)  
 
Join Date: Mar 2010
Location: Often in Jersey, but mainly in the past.
Age: 79
Posts: 7,812
Received 137 Likes on 64 Posts
RAAF Mirage IIIs called High Key entering the downwind leg at 14,000 ft ... quite stimulating to watch from the Tower, and I suspect even more so in the cockpit.
MPN11 is offline  
Old 19th Feb 2018, 09:18
  #4 (permalink)  
 
Join Date: Feb 2003
Location: Brighton
Posts: 973
Received 6 Likes on 6 Posts
Going back a few decades: for the Hunter we used 5-6000 ft agl as High Key, entering the downwind leg, 210 kt clean. Low Key, abeam touchdown, ideally 3000 ft.
kenparry is offline  
Old 19th Feb 2018, 09:25
  #5 (permalink)  
 
Join Date: Jul 2003
Location: Near the coast
Posts: 2,371
Received 553 Likes on 151 Posts
Heights

I should have added that HK is approx 4500’ and LK approx 2500’.

Always think wind of course!

BV
Bob Viking is offline  
Old 19th Feb 2018, 09:44
  #6 (permalink)  
 
Join Date: Mar 2001
Posts: 1,058
Received 24 Likes on 11 Posts
Wot's a PFL ?

LFH (Glider 1961)

..........
Lordflasheart is offline  
Old 19th Feb 2018, 09:47
  #7 (permalink)  
 
Join Date: Feb 2003
Location: Brighton
Posts: 973
Received 6 Likes on 6 Posts
Wot's a PFL ?
Practice Forced Landing
kenparry is offline  
Old 19th Feb 2018, 10:04
  #8 (permalink)  
 
Join Date: Mar 2010
Location: Often in Jersey, but mainly in the past.
Age: 79
Posts: 7,812
Received 137 Likes on 64 Posts
Different from an AFL, as gliders do that all the time.
MPN11 is offline  
Old 19th Feb 2018, 11:10
  #9 (permalink)  
 
Join Date: Dec 2000
Posts: 659
Likes: 0
Received 0 Likes on 0 Posts
Recall having a ride in a Belgian 104 (which wasn't for the faint-hearted) and being told their High Key was 22,000ft!
Chris Kebab is offline  
Old 19th Feb 2018, 11:15
  #10 (permalink)  
 
Join Date: Apr 2003
Location: SWAPS Inner
Posts: 567
Likes: 0
Received 0 Likes on 0 Posts
There is a long thread on this on a certain other place that concerns flying little planes with a mix of outrage from some GA pilots and enlightenment from others, that people should use such terms when flying in 'GA' and not 'Military' airspace. For some people, being an ex-mil pilot winds them up no end before you've even got past the 'hello how are you' stage... Maybe previous offerings of pomposity have wound them up or maybe its just resentment at not having made it into the RAF. Either way, an awareness of different ways of skinning a cat and that others may not understand the words you use may be the way forward...

Or just join for a break to land every time...
thunderbird7 is offline  
Old 19th Feb 2018, 11:18
  #11 (permalink)  
 
Join Date: Apr 2003
Location: SWAPS Inner
Posts: 567
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Chris Kebab
Recall having a ride in a Belgian 104 (which wasn't for the faint-hearted) and being told their High Key was 22,000ft!
Just listened to Arnulf Hartl being interviewed about flying the F104 and there is an interesting bit about partial power/dead stick approaches!! For those who haven't listened, these are an excellent series of podcasts - normal blokes talking about the planes they have flown.
thunderbird7 is offline  
Old 19th Feb 2018, 11:33
  #12 (permalink)  
 
Join Date: May 2002
Location: Green and pleasant land
Posts: 658
Likes: 0
Received 0 Likes on 0 Posts
Someone will correct me with the precise details but ISTR that in the mighty Bullfrog, High Key was about 800', with Low Key about 400-500' depending on the CSLA and how that was going ....
cargosales is offline  
Old 19th Feb 2018, 11:43
  #13 (permalink)  
 
Join Date: May 2002
Location: Green and pleasant land
Posts: 658
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by thunderbird7
a mix of outrage from some GA pilots and enlightenment from others, that people should use such terms when flying in 'GA' and not 'Military' airspace. .... Either way, an awareness of different ways of skinning a cat and that others may not understand the words you use may be the way forward...

Or just join for a break to land every time...
I'm sure it wound up the civvies no end (and probably rightly so) when we practised diversions into a nearby civilian airfield. You could almost hear the amusement in the controllers voice there as he interupted whatever they were doing and said to his assembled throng ..

"All stations, clear the circuit immediately, military aircraft inbound" and their 'pi$$ed-offness' when a Bulldog trundled into sight, did an approach, not even a TnGo, and then bogged off again..
cargosales is offline  
Old 19th Feb 2018, 12:37
  #14 (permalink)  
 
Join Date: Jan 2007
Location: Lincolnshire
Age: 78
Posts: 104
Likes: 0
Received 0 Likes on 0 Posts
JP Mk3a and Mk5 Hkey @2500' agl, Lkey @ 1500' agl.
Lkey downwind abeam RW threshold.
cyclic35 is offline  
Old 19th Feb 2018, 12:48
  #15 (permalink)  
lsh
 
Join Date: May 1999
Location: uk
Age: 66
Posts: 381
Received 0 Likes on 0 Posts
Remember early Microsoft Flight Simulator?
It had red boxes in the sky, you flew through them to achieve the result required ie approach to land.

High Key, Low Key etc are "Key" points (or "Gates").
Achieve each gate in sequence and you should achieve your objective ie PFL.
If you are not at the required height, speed and position, you may be able to continue your (now modified) pattern or have to abandon it - with all that implies.

It formalises a procedure and makes it more likely that you will be successful in your task, be it practice or real - it gives you an early warning too if things are not going "to plan".

lsh

lsh is offline  
Old 19th Feb 2018, 13:03
  #16 (permalink)  
 
Join Date: May 1999
Location: Quite near 'An aerodrome somewhere in England'
Posts: 26,826
Received 271 Likes on 110 Posts
Cargosales wrote:
Someone will correct me with the precise details but ISTR that in the mighty Bullfrog, High Key was about 800', with Low Key about 400-500' depending on the CSLA and how that was going ....
For the Bulldog PFL, ideally you would approach the desired landing area at 80KIAS and 2-3000' agl before tracking to 'Point 1' or High Key when the initial aiming point 1/3 way into the field appeared immediately in front of the wing leading edge. Then decelerate to 75KIAS and keep gliding straight ahead until the touchdown point appeared just behind the trailing edge (Point 2). Then turn with 30° AoB to track crosswind, aiming at a selected feature and allowing for drift, until the touchdown point appeared immediately ahead of the tailplane (Point 3). That was 'Low Key', at around 1500' agl, when you started a continuous gliding turn at 20°AoB at 75KIAS with Inter flap aiming to run the touchdown point along an imaginary line from its location on the left side of the aircraft to directly in front of the windscreen. If you were getting below the line, you increased bank and held the picture until you regained the imaginary line, then ease off the bank and reassess. Once straight in to the field, provided you were certain of getting in and were not below 200' agl, you would lower full flap and use a touchdown aiming point closer to the downwind end of the landing area. We used to practise this down to 100' agl when dual or 250' agl for student solos.
BEagle is online now  
Old 19th Feb 2018, 13:29
  #17 (permalink)  
 
Join Date: May 2003
Location: London/Oxford/New York
Posts: 2,926
Received 139 Likes on 64 Posts
cargosales,


"All stations, clear the circuit immediately, military aircraft inbound"

In what world was that ever heard?
pr00ne is offline  
Old 19th Feb 2018, 13:50
  #18 (permalink)  
Gnome de PPRuNe
 
Join Date: Jan 2002
Location: Too close to Croydon for comfort
Age: 60
Posts: 12,648
Received 305 Likes on 170 Posts
Originally Posted by Chris Kebab
Recall having a ride in a Belgian 104 (which wasn't for the faint-hearted) and being told their High Key was 22,000ft!
I think one of my gliding instructors had flown WGAF F-104s at some point in his career.
treadigraph is online now  
Old 19th Feb 2018, 14:01
  #19 (permalink)  
 
Join Date: May 2002
Location: Green and pleasant land
Posts: 658
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by pr00ne
cargosales,


"All stations, clear the circuit immediately, military aircraft inbound"

In what world was that ever heard?
This one. At a civvy airfield in the West Mids that we were approaching to be precise.. I remember it clearly because it was so dramatic and pointlessly OTT..
cargosales is offline  
Old 19th Feb 2018, 14:18
  #20 (permalink)  
 
Join Date: May 2002
Location: Green and pleasant land
Posts: 658
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by BEagle
Cargosales wrote:

For the Bulldog PFL, ideally you would approach the desired landing area at 80KIAS and 2-3000' agl before tracking to 'Point 1' or High Key when the initial aiming point 1/3 way into the field appeared immediately in front of the wing leading edge. Then decelerate to 75KIAS and keep gliding straight ahead until the touchdown point appeared just behind the trailing edge (Point 2). Then turn with 30° AoB to track crosswind, aiming at a selected feature and allowing for drift, until the touchdown point appeared immediately ahead of the tailplane (Point 3). That was 'Low Key', at around 1500' agl, when you started a continuous gliding turn at 20°AoB at 75KIAS with Inter flap aiming to run the touchdown point along an imaginary line from its location on the left side of the aircraft to directly in front of the windscreen. If you were getting below the line, you increased bank and held the picture until you regained the imaginary line, then ease off the bank and reassess. Once straight in to the field, provided you were certain of getting in and were not below 200' agl, you would lower full flap and use a touchdown aiming point closer to the downwind end of the landing area. We used to practise this down to 100' agl when dual or 250' agl for student solos.
Thanks BEags .. that sounds more like it. Guess I was thinking of normal circuit height, not PFLs.

Cheers, CS
cargosales is offline  


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.