On Oct 15, 6:16 am, Stefan wrote:
Andrew Sarangan schrieb:

No it is not a sixth sense. It is the right combination of numbers and
sight picture. Sight picture only helps when you are fairly low (ie
500' AGL) and on final approach. During downwind or base you don't
have a good sight picture to tell whether you are going to be too high
or too low. You have to rely on your altimeter and use several
'target' altitudes until you turn final.

I disagree. Of course the alitmeter can be very helpful, but only if you
know the ground elevation and if you are sure your current altimeter
setting is correct.

As this is often not the case, think in angles. Angles stay the same
regardless of height and distance.

I have to disagree. Altimeter errors are pretty minor compared to
visual errors. Even if you never changed the altimeter setting since
takeoff, you can't be more than a few tens of feet off unless you are
flying through some huge weather system, or are a long way off from
home. Unless you are in hilly terrain, ground elevation is only a
quick glance away from a sectional chart. If you are doing the landing
at an airport, then you know exactly what the elevation is.

It is true that angles stays the same regardless of height and
distance, but that only applies for a straight line. When you are on
downwind or base you are only guessing what your approach angle might
be. You are relying heavily on how high it "feels" and how far it
"feels", and how that might transpire into a good approach angle after
you turn final. Once you are on final, your argument is correct that
you should be able to do everything by the visual angle. But by that
time it is too late to make large changes, only minor changes. This is
the reason many pilots find practice engine outs to have inconsistent
results. If you set target altitude for different positions prior to
reaching final, the consistency significantly improves. I've been
teaching this way and I rarely had a student fail to make a runway on
a practice power-off approaches.

Someone else mentioned a sticking altimeter when the engine is not
running. I never had a real engine failure so I can't disagree with
that, but every airplane I have flown in shows an altitude changes
with daily pressure changes even when it is parked in the hanger. The
vibrations in a parked airplane must be much smaller than one that is
airborne, with or without an engine.