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Steep approaches (in VMC) - do you fly them, and why, or why not?

Peter, yes, a homebuilt four cylinder Lancair as I remember that would be going pretty fast on final. The landing gear hit the fence apparently and it flipped over forwards, ending up upside down.

That’s absolutely bloody tragic. But… a forced landing at 80-90kt is going to need a large dose of luck, in a plane which will disintegrate readily when it hits something. I looked at the IV recently (as I tend to after every 5hr+ flight with a 70kt headwind…) but reading some of the stuff is a bit scary. Also it needs 1000m+ of tarmac.

Administrator
Shoreham EGKA, United Kingdom

On a steep approach, especially at airfields with either air/ground/afis only, or no radio, is there not a risk of faster aircraft overruning slower aircraft – there are quite a few mid airs where a faster, heavier aircraft has descended on the local puddle jumper.

Some aircraft, heavier single engine, multi engine, normally carry some power through into the round out phase, with power being reduced to idle in the flare. In the case of some heavier single engine aircraft, eg 182 at forward CofG, this is to ensure there is good elevator responsiveness at the forward CofG; the Wichita accountants having eliminated the variable incidence trim system it was originally designed with back in 1961. The 182 is notorious for wrinkled firewalls due to people trying to fly it like a 172. In a multi engine (not perhaps a mixmaster 337) reducing power to idle immediately reduces accelerated propeller slipstream over the wings, and you also get two nice air brakes courtesy of the windmilling drag effect. Hence keeping some power on, say zero thrust, until you have rounded out and are in ground effect.

Finally the ACME Wannabe school is trying to inculcate into motor memory and pre Multi Crew Cooperation training concepts such as approach gates and stabilised approaches – these always involve making an approach under power. The CPL does require demonstration of a PFL with a complex retractable, but from CPL onwards I would suggest all training (outside a SE PFL) is in a powered approach configuration.

For avoidance am not critiquing steep approaches, except the lookout point in the first sentence, and in fact always try when possible, to conduct a PFL from the overhead, making way for circuit traffic.

Oxford (EGTK), United Kingdom

I personally love steep high drag approaches (gear and flaps down, prop set for cruise) in my Bonanza and using power off to the runway when I have it made. I use the emergency landing approach speed in the POH. It is higher than the short field approach speed of 71 Kts by an additional 12 knots. It provides for the additional energy required for the flare and in my experience produces similar results as the short field landing. The descent rate requires an earlier start to the flare, but energy dissipates rapidly. Using the short field speed in the glide will prang the airplane as the momentum is not arrested in the flare.

Steep approaches have several advantages. They provide greater obstacle clearance. They are more accurate in terms of the touchdown point. They don’t need power to make the runway. They use less runway. They are practice for proper handling when there is an engine failure. They teach the sight picture needed to avoid a stall and to judge when and if to use high drag configurations in an emergency. A common error in an emergency is to put the gear and flaps down too soon and subsequently not being able to glide to the intended touchdown point.

The main disadvantages are they can be more uncomfortable for passengers whose ears are not able to adjust to the descent rate as well and they can scare some passengers.

KUZA, United States

Brilliant post, NCYankee

Including the passenger scaring bit

Administrator
Shoreham EGKA, United Kingdom

What was the fuel servo issue? Was it icing?

No, it was a mechanical issue. The servo was rebuilt at the last annual prior to the incident.

United States

I enjoyed your post NCYankee, but interested to know why you think the approach angle makes the touchdown more accurate?

London area

Controlled crash at a point? The highest precision landing is vertical, although a bit hard.

Joking aside, with speed nailed in a glide approach, especially in a gliding anvil as the Bonanza, you get a short, sharp flare that just arrests the descent, with not much energy left for gliding along the runway, even if a few knots off speed either way.. and the Bonanza undercarriage is quite forgiving if you get it wrong a bit.. not something I would like to do in a Mooney, though.

Biggin Hill

I enjoyed your post NCYankee, but interested to know why you think the approach angle makes the touchdown more accurate?

Simple geometry. Draw a descent angle to the touchdown aiming point. Use a 3 degree descent angle and a 6 degree descent angle. Assume an error of +/- a half a degree in each case. The error covers a larger distance in the shallower descent angle.

KUZA, United States

That argument assumes that you don’t correct the flight path on the way down though?

Surely for any approach angle the technique is the same? The only advantage a steep approach may have is keeping the aiming point visible for longer. If you watch spot landing competitions, competitors don’t tend to fly noticeably steeper (in fact one cheat is to flare early, hold it in ground effect and chop the power to drop in.)

London area
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