Which heading for an emergency letdown

[pelmet]

Just read this and found it interesting....

You are in an aircraft with minimal instruments but you do have a turn and slip along with the standard ASI and altimeter. Maybe even an artificial horizon, maybe not. But you are stuck above a cloud layer with good vis and clear area below and have decided to do an emergency letdown through the clouds even though you have limited instrument time. What heading(s) would be best and what headings(s) are the worst to do the letdown. Approximations are fine. And no spins allowed(which could be the best way actually).

[Big Pistons Forever]

090 or 270

[lownslow]

A Cessna 150 manual I have around here says the heading doesn’t matter. Their emergency let-down procedure is to trim for 200-300fpm descent, keep the skid ball centred with rudder, and sit on your hands. Hedley would love that procedure as it dovetails nicely into his long standing theory that planes don’t crash planes, pilots crash planes.

[youhavecontrol]

Is the heading chosen because of acceleration errors in the magnetic compass? If so, I'd choose North/South over East/West... just a guess though.
Acceleration looks like a turn towards the North, when on a East or West heading, and Deceleration looks like a turn towards the South on a East or West heading on a magnetic compass. (A.N.D.S.) So Northern or Southern headings would have the least chance of this error appearing.

Really though, I wouldn't care much about the heading, as I'd be monitoring my turn co-ordinator and airspeed over anything else.

[JasonE]

I'd just turn on the autopilot and reduce the power

[rookiepilot]

A Cessna 150 manual I have around here says the heading doesn’t matter. Their emergency let-down procedure is to trim for 200-300fpm descent, keep the skid ball centred with rudder, and sit on your hands. Hedley would love that procedure as it dovetails nicely into his long standing theory that planes don’t crash planes, pilots crash planes.

If I remember correctly, that's why those three students that fell asleep out of Brampton, all survived. I believe that's accurate

[ekg]

A Cessna 150 manual I have around here says the heading doesn’t matter. Their emergency let-down procedure is to trim for 200-300fpm descent, keep the skid ball centred with rudder, and sit on your hands. Hedley would love that procedure as it dovetails nicely into his long standing theory that planes don’t crash planes, pilots crash planes.

If I remember correctly, that's why those three students that fell asleep out of Brampton, all survived. I believe that's accurate

Is there a thread / publication about this? Sounds interesting

[B208]

If the area below is clear, heading does not matter. Reduce power slightly, don't touch trim, keep needle and ball centred.

[TeePeeCreeper]

090 or 270

Why?

[Creston]

Why 090 or 270? Because in at least south west BC, your panic will be short lived.

[waterdog]

B208 is right.
I read a great book on this just recently, "IFR for the VFR pilot". They talk about a lot of fundamentals that simple are not taught or I forgot.
Basically....
When the plane is trimmed it is cruise control for an airspeed, the wing and the horizontal stabilizer are in balance and you are level. If you simple reduce power, either RPM in a fixed pitch or MP in a constant speed prop you will descend at a predictable rate, usually 1" ( 100rpm) reduction per 100 FPM descent. Reduce 3" MP, the nose will slowly drop, the plane will begin to descend ( at approx 300 FPM) airspeed will re-establish at what you had the plane trimmed for only with less power, its in a descent. When you get to the altitude you want, add back in the original power settings and the plane will level off. Don't touch the trim and don't touch the yoke. Steer the plane with your feet and no more then 10-15 degrees of bank, basically sit on your hands.
I was playing with this the other day and it works like a charm, great thing to practice on a VFR day. One of the points that they drilled home is that a VFR pilot has absolutely no chance of flying on instruments for any length of time. There are lots of cases where IFR pilots or pilots who are working on their IFR ticket get into trouble on instruments and they have a lot more then the 5hrs of time us VFR guys do.
Either way its a great thing to practice and certainly to know.

K

[photofly]

It’s certainly worth practicing; because many pilots - when they start to feel uncomfortable with some element of the flight - grab on tight to whatever comes to hand, which is typically the yoke with one hand and the throttle with the other. And then they start stirring with both hands, because, you know, when things are difficult it’s important to be a pilot, and pilots move the flight controls a lot, and if you’re not moving the controls a lot you’re not being a good pilot. Right?


Pet peeve: student has the plane perfectly trimmed for level flight, nice and relaxed, throttle locked off at cruise power, light grip on yoke, eyes are out the window, everything hunky dory. Student puts on hood. Seat goes three clicks forward, head gets buried in instrument panel, left hand death-grips yoke, right hand starts to flick between throttle and trim in a ceaseless series of apparently random adjustments and within 20 seconds the aircraft is rising and falling hundreds of feet and banking left and right like a roller coaster ride.

[C.W.E.]

Student puts on hood. Seat goes three clicks forward, head gets buried in instrument panel, left hand death-grips yoke, right hand starts to flick between throttle and trim in a ceaseless series of apparently random adjustments and within 20 seconds the aircraft is rising and falling hundreds of feet and banking left and right like a roller coaster ride.

Typical anxiety response caused by fear of the unknown.

The unknown in this instance is that flying by reference to instruments only is far easier and more accurate than looking outside.

The most comfortable start to a flight for me is entering IMC right after lift off and flying by instruments only.

P.S. :

The use of a hood to simulate IMC is unorthodox and detrimental to teaching instrument flight.

Note:

The above is my personal opinion on the subject formed by decades of IMC flight, and teaching instrument flight.

[pelmet]

090 or 270

Why?

To reduce compass card swings which could increase the risk of a spiral dive.

[B208]

090 or 270

Why?

To reduce compass card swings which could increase the risk of a spiral dive.

Dude, if you are on a partial panel the compass is very much a secondary instrument; you only look at it to confirm heading and you never look at it while making a control input. On a partial panel your control instruments become needle, ball and airspeed; these form the hub of your hub and spoke scan. Needle and ball give you bank and airspeed gives you pitch. The compass, altimeter and VSI are your performance instruments. They are the spokes of the scan. If you want to execute a turn, scan the compass, note the heading then go back to your control instruments. Calculated how many seconds of turn are required to get to your desired heading, start your time, roll in. While in the turn scan instruments and time; do not look at the compass at all. When time is up, roll out, give everything a few seconds to stabilize then look at your compass and confirm you got to the desired heading.

[photofly]

I think he knows that

[B208]

I think he knows that

I do hope you're right.

[rookiepilot]

It’s certainly worth practicing; because many pilots - when they start to feel uncomfortable with some element of the flight - grab on tight to whatever comes to hand, which is typically the yoke with one hand and the throttle with the other. And then they start stirring with both hands, because, you know, when things are difficult it’s important to be a pilot, and pilots move the flight controls a lot, and if you’re not moving the controls a lot you’re not being a good pilot. Right?


Pet peeve: student has the plane perfectly trimmed for level flight, nice and relaxed, throttle locked off at cruise power, light grip on yoke, eyes are out the window, everything hunky dory. Student puts on hood. Seat goes three clicks forward, head gets buried in instrument panel, left hand death-grips yoke, right hand starts to flick between throttle and trim in a ceaseless series of apparently random adjustments and within 20 seconds the aircraft is rising and falling hundreds of feet and banking left and right like a roller coaster ride.

Break students last 2 fingers. Three fingers on the yoke is almost always quite enough in IMC.

Seriously, I was fortunate to do some training (mainly holds) in actual, I discovered one can easily control the aircraft in turns with two or three fingers, even in some chop. Hard to overcontrol that way.

[pelmet]

Why?

To reduce compass card swings which could increase the risk of a spiral dive.

Dude, if you are on a partial panel the compass is very much a secondary instrument; you only look at it to confirm heading and you never look at it while making a control input. On a partial panel your control instruments become needle, ball and airspeed; these form the hub of your hub and spoke scan. Needle and ball give you bank and airspeed gives you pitch. The compass, altimeter and VSI are your performance instruments. They are the spokes of the scan. If you want to execute a turn, scan the compass, note the heading then go back to your control instruments. Calculated how many seconds of turn are required to get to your desired heading, start your time, roll in. While in the turn scan instruments and time; do not look at the compass at all. When time is up, roll out, give everything a few seconds to stabilize then look at your compass and confirm you got to the desired heading.

I think he knows that

I do hope you're right.

This info comes straight from a POH that I read in the past ten days or so. Which I suppose is FAA certified. I found it interesting.

Congratulations to BPF for getting the correct answer(and pretty much right away[took 16 minutes]).

[B208]

To reduce compass card swings which could increase the risk of a spiral dive.

Dude, if you are on a partial panel the compass is very much a secondary instrument; you only look at it to confirm heading and you never look at it while making a control input. On a partial panel your control instruments become needle, ball and airspeed; these form the hub of your hub and spoke scan. Needle and ball give you bank and airspeed gives you pitch. The compass, altimeter and VSI are your performance instruments. They are the spokes of the scan. If you want to execute a turn, scan the compass, note the heading then go back to your control instruments. Calculated how many seconds of turn are required to get to your desired heading, start your time, roll in. While in the turn scan instruments and time; do not look at the compass at all. When time is up, roll out, give everything a few seconds to stabilize then look at your compass and confirm you got to the desired heading.

I think he knows that

I do hope you're right.

This info comes straight from a POH that I read in the past ten days or so. Which I suppose is FAA certified. I found it interesting.

Congratulations to BPF for getting the correct answer(and pretty much right away[took 16 minutes]).

I wish you the best of luck with that.