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The most reliable way to do a forced landing? High Key / Low Key

I am getting to the end of the very good book by Buster1 and also referring to this and this, why is the “high key” and “low key” method taught seemingly only in the military?

Whereas the various ways taught in the PPL should work but actually often don’t (in the sense that the pilot often fails to reach the desired field or runway) the high key and low key method is claimed to work every time.

For most GA types, AIUI, you want to be at 1500ft AGL above the start (the landing point) of the runway, which is the High Key, pointing into the wind, and then commence the turn and aim to be at 1000ft at late downwind, which is the Low Key. This is based on most GA types descending at about 1000fpm. What I don’t quite get is how to achieve the first one, because (let’s assume you have loads of altitude to play with) an orbit will lose you about 1000ft, which doesn’t give you enough resolution to end up at 2000ft reliably.

Administrator
Shoreham EGKA, United Kingdom

High key and low key is the method in the Pooleys books and the way I was taught.

I would think 2000 ft above the mid-point is too high to do a reasonable circuit to land. I was taught that you should be at 2000 ft at the crosswind position. Even if you’re 2-300 ft too high or low when you get there you can adjust by flying a tighter or wider circuit or do some s-turns as you find yourself too high as you approach the crosswind leg.

EIMH, Ireland

Just checked the book and it’s actually 2500 ft at 3/4 nm upwind of the far end of the landing strip then 1500 ft on downwind 1/3 nm before a beam touchdown point.

EIMH, Ireland
We did lots of “high key – low key” (Ziellandungen) landings in PPL, easy enough when you know the strategy: Basically you aim for 2000 ft over ground/ airfield in landing direction – same altitude as you should fly cross country minimum here. So for the landing pattern you aim for a square circuit with engine idle – a bit like you would have in a dead engine emergency . 2000 ft altitude to loose in a square means for each side you see 500 ft lost on the gauge. You start right over the mid airfield with 2000 ft then turn 90 degrees right (or left for left hand pattern), fly till you have lost the first 500ft according to the gauge, turn another 90 degrees right till the next 500 ft are gone. So you will be 1000 ft above ground downwind somewhere – low key. Another 90 degrees right hand turn will position you for base and you loose another 500 ft just right for the last 90 degrees right for the last 500 ft to hit the runway safe enough. When you feel you are coming too low for the final you can skip the last 90 degrees right for a shorter approach to the runway. But most of the times it works out quite well. With a lot of head wind you will cut the final shorter to reach the runway. Or start the high key from the far end of the runway. I think we never used any flaps for the pattern, only in the final when you feel you will need them for brakes. A bit of slipping would be allright, but no engine help approved, that would mean you failed on this job. Anyway, you just watch your altitude indicator for these four square sides to loose 500 ft for each and you will hit the runway without much head scratching, glide ratios and speeds don´t matter. That square would look very differently with a Fokker triplane compared to a modern glider but the strategy is exactly same. Vic
vic
EDME

I learned to do it just like Vic just described. However, in the check ride the FE fiddled with the altimeter settings, declaring it INOP. He argued that one could not rely on the altimeter in an emergency and had to rely at the sight picture at all times.

Novice pilot
EDVM Hildesheim, Germany

MedEwok wrote:

He argued that one could not rely on the altimeter in an emergency and had to rely at the sight picture at all times.

Wow, I understand a little bit that one should be able to judge height by your eyes to a certain extent but that seems a bit exaggerated. The altimeter will not fail when the engine does…

Sweden, Sweden

MedEwok wrote:

He argued that one could not rely on the altimeter in an emergency and had to rely at the sight picture at all times.

The described method (500 ft -steps) might be good as a rule of thumb, but at my homebase I can train only 1000ft AGL due to airspace. I solely rely on visual reference to the RWY and it it mostely works okay with a quite narrow circuit That way I am best prepared, if I don’t have – for what ever reason – the 2000ft AGL – I guess….

Last Edited by europaxs at 28 Dec 07:05
EDLE

Since I did my last high key/low key (successfully) yesterday as part of the revalidation, few small comments:
(1) While in training at a well known airfield you can do right or left turns, in a real emergency you should only do left turns (from seat front left). Much easier to check your direction, wind drift etc relative to your desired landing area which may not be a well visible strip of tarmac. For that reason our club exclusively trtains left hand circuits
(2) If you know you have a significant wind (10kn or above) – shorten your down wind, as it will carry you further downwind and slow you down on final
(3) Gear down only on final changes the sink rate dramatically not more than a normal landing but a bit more than the 4 * 500ft method assumes… I shortened the downwind leg by 100ft vertical and came out nicely (starting as suggested at 2000ft AGL with the threshold just in view to the left)

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EDM_, Germany

europaxs wrote:

The described method (500 ft -steps) might be good as a rule of thumb, but at my homebase I can train only 1000ft AGL due to airspace. I solely rely on visual reference to the RWY and it it mostely works okay with a quite narrow circuit That way I am best prepared, if I don’t have – for what ever reason – the 2000ft AGL – I guess….

You can obviously adjust the lenght of the legs, and if you have stabilized your sink rate you could time it just as well. But who has really ;-)

In a plane with two altimeters and a GPS I find the high key/low key a good training exercise, but it will obvioulsy not be applicable every time and everywhere.
As far as I can tell the high starting point may be related to the pre-SERA minimum x-country altitude of 2000ft AGL in Germany…

...
EDM_, Germany

I must try the “square” method. However

You start right over the mid airfield with 2000 ft

is the Q I originally asked: how do you achieve the 2000ft (or whatever is desired) if you are gliding down from some greater altitude? The chances of the engine failing at 2000ft above the runway is practically zero. Yet a good number of people who got engine failures at say 10k-20k have failed to reach a runway which was within reach.

Administrator
Shoreham EGKA, United Kingdom
103 Posts
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