What Does High Key mean when in the circuit?
Ecce Homo! Loquitur...
I still have, tucked away in a filing cabinet, the NOTAM with the Space Shuttle emergency landing profile into Fairford with, along with the flight path/timing circle details such pearls of information that it would be an unpowered approach......
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I believe we have a winner!!!!
Great reply, ORAC. And I thot the initial question was a really great one, and I don't know what the sailplane/glider folks call there position in the pattern ( we yanks call it pattern versus circuit)
The shuttle circle was really well thot out and allowed various approach headings and even altitudes.
Having practiced the precautionary flameout or engine problem patterns many times back in my early days, the terms "high key" and "low key" ring a special bell. And then comes the day you have to do it for real, heh heh. And I did.
Was shot up and leaking fuel like crazy, so deadsticked my A-37 into the big airport at Saigon. The jet was brand new and we did not even have a procedure in the books yet, so I added speeds from the T-37 trainer model procedure and recalled my numerous practice "circuits' from my T-33 experience. Was able to get the critter onto the rwy and only had blown main gear damage and all those holes in the fuel lines. So the jet flew again a few weeks later.
USAF prohibited flameout approaches a few years later, and the F-16 was the first one that was allowed to practice and actually do some when the motor failed within few minutes of a suitable field. High key was like 8,000 ft above the field and low key maybe 3500 feet or so. We played the altitude more than distance from the rwy, but that kite had a really great glide ratio ubntil you lowered the gear. We had one troop do a straight in deadstick over at Wendover, UT. Whew!
Gums sends...
The shuttle circle was really well thot out and allowed various approach headings and even altitudes.
Having practiced the precautionary flameout or engine problem patterns many times back in my early days, the terms "high key" and "low key" ring a special bell. And then comes the day you have to do it for real, heh heh. And I did.
Was shot up and leaking fuel like crazy, so deadsticked my A-37 into the big airport at Saigon. The jet was brand new and we did not even have a procedure in the books yet, so I added speeds from the T-37 trainer model procedure and recalled my numerous practice "circuits' from my T-33 experience. Was able to get the critter onto the rwy and only had blown main gear damage and all those holes in the fuel lines. So the jet flew again a few weeks later.
USAF prohibited flameout approaches a few years later, and the F-16 was the first one that was allowed to practice and actually do some when the motor failed within few minutes of a suitable field. High key was like 8,000 ft above the field and low key maybe 3500 feet or so. We played the altitude more than distance from the rwy, but that kite had a really great glide ratio ubntil you lowered the gear. We had one troop do a straight in deadstick over at Wendover, UT. Whew!
Gums sends...
Last edited by gums; 20th Feb 2018 at 00:02. Reason: sp
TNX, Megan. Nice video and newer HUD display than I had.
I was instructor for the Wendover guy and possibly the one at Tampa/St Pete.
The pure hydrazine EPU only lasted 6 or 7 minutes, but you could help by being smooth and easing the hydraulic demand. Another thing was using the jet fuel starter if you had gas left but the big motor was tits up. That allowed some hydraulic pressure that the EPU didn't have to provide.
neat thead....
I was instructor for the Wendover guy and possibly the one at Tampa/St Pete.
The pure hydrazine EPU only lasted 6 or 7 minutes, but you could help by being smooth and easing the hydraulic demand. Another thing was using the jet fuel starter if you had gas left but the big motor was tits up. That allowed some hydraulic pressure that the EPU didn't have to provide.
neat thead....
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High key, low key, base, finals... But there is a diagonal as well to keep the landing area in sight all the way round the circuit, and every circuit is a one-off due to the need to arrive in the right place (or a suitable place) on the airfield. Finding oneself in 6 knots of sink can be 'interesting'.
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.
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.
High Key is now 2500-3500ft agl and Low Key is now abeam the Initial Aiming Point, around 1500ft but can be above or below. The imaginary line is called the Sight Line Angle.
A field approach is far easier because if you find yourself high or low, you have many choices to correct it: change the landing direction, change the field, S-Turn to lose height or even sideslip (used by myself last week on a Precautionary Forced Landing). To a runway, there's less choice but varying the angle of bank varies the touchdown point so it can be quite easily controlled.
We try to teach our students to use plain language when doing "something military" at civilian airfields, so High Key would be "Deadside, 3000ft, right-hand glide approach to runway XX" but often we have to ditch the military stuff and fly square and very wide circuits. Shame though, cos even in a Tutor, a VRIAB is good fun!
I well remember an old and hairy ground instructor's reaction to "High key" Low key", having had several engine failures himself on singles , including with the J.P.
His method, from medium altitude, was to head for the overhead of the nearest R.A.F. Airfield ,broadcasting his intentions and getting the circuit cleared. Then spiral down until by aspect it was comfortable to get on to one of the runways and then deadstick well in.
He admitted having a dilemma on one occasion as whether to go for Cranwell or Barkston. He chose the latter:
"Since that was where I'd left my bike"
Of course finding an RAF Airfield now is a bit more difficult..........
His method, from medium altitude, was to head for the overhead of the nearest R.A.F. Airfield ,broadcasting his intentions and getting the circuit cleared. Then spiral down until by aspect it was comfortable to get on to one of the runways and then deadstick well in.
He admitted having a dilemma on one occasion as whether to go for Cranwell or Barkston. He chose the latter:
"Since that was where I'd left my bike"
Of course finding an RAF Airfield now is a bit more difficult..........
I still have, tucked away in a filing cabinet, the NOTAM with the Space Shuttle emergency landing profile into Fairford with, along with the flight path/timing circle details such pearls of information that it would be an unpowered approach......
Used to do a glide approach into Muharraq in the VC10 many years ago. IIRC 30000 feet, 30 nms DME, select idle power, use combination of speed brakes, gear and flaps/slats to adjust glide path, low key at about 2500 feet abeam touch down IAP, turn final and select full flap - or not.
Used to do a glide approach into Muharraq in the VC10 many years ago. IIRC 30000 feet, 30 nms DME, select idle power, use combination of speed brakes, gear and flaps/slats to adjust glide path, low key at about 2500 feet abeam touch down IAP, turn final and select full flap - or not.
Gentleman Aviator
Try that with an engine seized, especially if one cannot feather the prop, and one comes down rather quicker.
"Lowering half flap to simulate the drag of a dead engine".
Always wondered how accurate that was; certainly "forgetting" it for a bit made a useful increase in range............
Avoid imitations
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I well remember an old and hairy ground instructor's reaction to "High key" Low key", having had several engine failures himself on singles , including with the J.P.
His method, from medium altitude, was to head for the overhead of the nearest R.A.F. Airfield ,broadcasting his intentions and getting the circuit cleared. Then spiral down until by aspect it was comfortable to get on to one of the runways and then deadstick well in........
His method, from medium altitude, was to head for the overhead of the nearest R.A.F. Airfield ,broadcasting his intentions and getting the circuit cleared. Then spiral down until by aspect it was comfortable to get on to one of the runways and then deadstick well in........
Avoid imitations
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Did them too in the Ten, but of course those figures, for whatever aircraft, is invariably for a PFL (ie practice). So the engine was at idle. Try that will an engine seized, especially if one cannot feather the prop, and one comes down rather quicker. However, rate of descent does not matter if one flies the 'constant aspect technique'. I works for me in a Bulldog and it worked for me in the VC10.
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ORAC
I still have, tucked away in a filing cabinet, the NOTAM with the Space Shuttle emergency landing profile into Fairford with, along with the flight path/timing circle details such pearls of information that it would be an unpowered approach……
I still have, tucked away in a filing cabinet, the NOTAM with the Space Shuttle emergency landing profile into Fairford with, along with the flight path/timing circle details such pearls of information that it would be an unpowered approach……
[email protected]
Watched/listened to the shuttle return to Canaveral in the 80s with them calling heights and speeds over the radio, it's one hell of a glide approach as they were over the Gulf of Mexico still at Mach 25! Bizarrely, you hear a double sonic boom as they come back through the sound barrier.
Watched/listened to the shuttle return to Canaveral in the 80s with them calling heights and speeds over the radio, it's one hell of a glide approach as they were over the Gulf of Mexico still at Mach 25! Bizarrely, you hear a double sonic boom as they come back through the sound barrier.
The cockpit was redesigned to be the same as the shuttle, it was flown using the same HGS/HUD. If I remember correctly the technique was to start around 37000ft over the airport, main gear down, flaps into a neg position, thrust reversers deployed and reverse thrust applied, the descent profile was almost identical to the shuttle arriving on finals following the shuttle PAPI system to about 5000ft for a go-around.
The idea was to get the descent profile correct not the actual landing, I seem to remember there was a magazine article published describing the flight profile somewhere in the eighties.
Last edited by Above The Clouds; 22nd Feb 2018 at 12:06.
