Emergency Descent Procedures

[Bryanmooney]

Guys,

In the POH of my 1967 Mooney M20C with a 0-360 there is no emergency descent procedures. What would you guys do in case of needed emergency descent? Thanks for advice.

[Bryanmooney]

Correction 1976 Mooney M20C

[Bill_Pyles]

This is for my J

 

Emergency descent--gear down

Power---idle

Airspeed---161

Gear---down

Airspeed---190

Flaps---up

Cowl flaps---closed

Power as required to maintain 300 DF CHT

 

[201er]

I'd say it depends on what the emergency is. If it's a question of getting down as quickly as possible I would slow the heck down, get gear down, flaps down, and fly a tight spiral. Drops like a brick in a steep turn.

[Bryanmooney]

So drop everything then any thoughts on turn bank degree?

[rob]

By Emergency descent I assume you mean a fire? That's about the best motivation I can think of to get the airplane down in a hurry.

If so, power to idle and bank angle is as steep as you can manage and as stated above, a tight spiral. I would leave the gear up; simply because that way I can go ahead and land in a field or rough area without fear of snagging the gear and flipping. If I want to put the wheels out when a landing spot is made, I'll have that option. To me, gear up leaves more options down the road....

This is a part of the commercial criteria, or at least it was on my check ride.... Give it a shot with a competent instructor; you'll be amazed at how quickly you can descend and at how low the IAS will remain.

In a true emergency, you worry about the stated goal: getting the airplane on the ground as quickly and safely as possible. Don't worry about specific bank angles, airspeed, or engine instrumentation, worry about a landing spot and how to get to it quickly and safely.

[Bryanmooney]

Sounds great thank you. I did it in a Cessna during initial flight training but that is it. Fire is what this is in regards to.

[John Pleisse]

Bill Pyles procedure is dead on, except half flaps should be added IMO (white arc not required). This nets me -2400fpm w/green arc IAS (also a 201).

[John Pleisse]

So drop everything then any thoughts on turn bank degree?

 

 

Up to 60, but practice with a knowledgeable CFI first. I follow the Bonanza PPP data for this. Everything down is easier and effective enough.

[jetdriven]

I have practiced an emergency descent in our plane.  Power idle, mixture ICO, gear down at 153 MPH IAS, and pitch for that speed, with 45 degree bank,  We were seeing something like 4,000 FPM. I'd guess that a descent at redline with gear down would be closer to 6,000 FPM

 

I wouldn't consider descending at any lower speed or with flaps. you need the maximum drag and the most you can make is gear down at the limit speed with no power at the crank.  Idle is still some power.

 

If the airplane was really on fire, I'd descent at redline or 10% higher (design dive speed)  with the gear down.  You won't structurally damage the airplane.  You will lose the gear doors, but if you burn in the airplane you lose everything, including your life.  The time before the fire kills you is only perhaps 90 seconds to two minutes, get it on the ground without regard for anything else but time.

[Jamie]

....pop the speed brakes....

 

(Yes, this is probably trolling the "if you plan your emergency descent properly you won't need them " crowd.)

[RocketAviator]

By Emergency descent I assume you mean a fire? That's about the best motivation I can think of to get the airplane down in a hurry.

If so, power to idle and bank angle is as steep as you can manage and as stated above, a tight spiral. I would leave the gear up; simply because that way I can go ahead and land in a field or rough area without fear of snagging the gear and flipping. If I want to put the wheels out when a landing spot is made, I'll have that option. To me, gear up leaves more options down the road....

This is a part of the commercial criteria, or at least it was on my check ride.... Give it a shot with a competent instructor; you'll be amazed at how quickly you can descend and at how low the IAS will remain.

In a true emergency, you worry about the stated goal: getting the airplane on the ground as quickly and safely as possible. Don't worry about specific bank angles, airspeed, or engine instrumentation, worry about a landing spot and how to get to it quickly and safely.

Been there done that.... But if you are going to land on a Paved Runway during this practice... PUT THE GEAR DOWN BEFORE YOU LAND>>.. otherwise it is very expensive!  During our practice we dropped like a rock during our maneuver with the gear up!  I would say looking back now to work up to the high rate of descent through multiple practice attempts and like Byron suggest it may be best not to take it all the way to a landing.  In some if not most cases where you have a true emergency you may not be on top of a runway and SHOULD land gear up!

[aviatoreb]

I have practiced an emergency descent in our plane.  Power idle, mixture ICO, gear down at 153 MPH IAS, and pitch for that speed, with 45 degree bank,  We were seeing something like 4,000 FPM. I'd guess that a descent at redline with gear down would be closer to 6,000 FPM

 

I wouldn't consider descending at any lower speed or with flaps. you need the maximum drag and the most you can make is gear down at the limit speed with no power at the crank.  Idle is still some power.

 

If the airplane was really on fire, I'd descent at redline or 10% higher (design dive speed)  with the gear down.  You won't structurally damage the airplane.  You will lose the gear doors, but if you burn in the airplane you lose everything, including your life.  The time before the fire kills you is only perhaps 90 seconds to two minutes, get it on the ground without regard for anything else but time.

 

Hi Byron.  Why no flaps?  That's more drag, yes?  I know the speeds you cite are above Vf, but they are more drag so if you are on fire, don't we want to put out as much drag instead?

[chrisk]

There were two procedures listed for my M20K, both power off.  One at max speed with gear up.  The other with gear down at max gear speed.  The POH indicates the choice should be made on the amount of distance you want to cover.   Shorter distance is with the gear down.  --Either way, it can take a long time to get down if you are at 20,000+ feet. 

 

My training on the other hand was in a F.  Gear down and spiral seems very effective.

[jetdriven]

Hi Byron. Why no flaps? That's more drag, yes? I know the speeds you cite are above Vf, but they are more drag so if you are on fire, don't we want to put out as much drag instead?

Flaps add more drag (and lift) but you have to fly at a lower airspeed to use them. The airplane is closer to best glide speed at the top of the white arc, you are really only 20 knots above it. . Drag rises to the square root of the airspeed, however, and the extra 20-25 knots (and really you can go a lot faster) by flying gear down and flaps up will be a greater FPM descent. Exceed the flap speed and you can cause structural failure of the airplane. Exceed gear down speed (we are talking real emergency here) and you damage the gear doors, but the descent rate is pretty breathtaking. Try it both ways and report back.

[201er]

Do you think, in theory, that you will lose altitude quicker with the high drag spiral or in a spin?

[Hank]

My C drops like the proverbial rock with idle power, cruise IAS and ~45-50 degree bank spiral. Putting out flames would be higher speed to extinguish them, level off to bleed speed, then spiral down at lower IAS and higher vertical speed, right?

[rob]

Again, I think the point is being confused here. The stated goal is to get on the ground as soon as possible. Some of us seem to think that a low airspeed/draggy plane is required to accomplish this. I disagree. The point is to go down quickly, so your concern should be the vertical speed.

I personally wouldn't waste time slowing down to gear and flap speed if I were on fire. Id immediately reduce power and use the bank angle to eliminate lift. The airplane will go down at speeds you won't believe unless you've tried it.

[Hank]

Do you think, in theory, that you will lose altitude quicker with the high drag spiral or in a spin?

 

In theory, recovery from a one-turn spin may require 2000' or more--mess it up and you're done. I'd rather spiral down, clean. It was >2000 fpm the last time I tried it, clean, ~140 mph IAS, 45-50º banked spiral with no sensation that the floor was falling out beneath me.

[John Pleisse]

rob, on 23 Oct 2013 - 10:33 PM, said:

Don't worry about specific bank angles, airspeed, or engine instrumentation, worry about a landing spot and how to get to it quickly and safely.

 

 

This really brings up a critical point. 4,000-6,000 fpm is great practice. But control is critical. You want to arrive straight in or 1,000 abeam without your ear drums blown and enough wits about you to get it on the ground.

[jlunseth]

The J and K manuals describe two possible procedures for an emergency descent.  One is to slow to gear speed, drop the gear, and then descend at max gear extended speed, which is 132 in my 231.  The other POH procedure is to descend clean at Vne.  My manual says that in both configurations the aircraft will arrive at the ground in the same amount of time, but the Vne descent results in covering more ground than the gear down descent.  So one factor would be, I guess, how far you need or want to go to get to a landing site.  The manual says that the gear down method results in an easier work load for the pilot.  No doubt.

 

A spiral down at a fairly steep bank would be a way to descend essentially straight down, probably gear extended speed would be the choice for that.

 

My personal view is that it depends.  It depends on why you are in need of doing the descent, and where you need to go.

 

If you need to do the descent because there is smoke coming out of the engine and the paint krinkles, there is no doubt in my mind of the correct response.  Fuel off, mixture off, vents off, leave the mags on (to allow fuel in the lines to be burned in normal combustion rather than in the fire), and a Vne descent.  The reason is that while the Vne descent would be risky, the fire needs to be immediately dealt with or you may never reach the ground alive, and the best chance of that is to cut all fuel off and try to blow it out.  If you can get the fire out, then you might consider reducing the dive and looking at better landing options.  If you are just a few thousand off the ground when the fire happens, perhaps there would be time for the slower 132 knot gear extended descent, but the gamble would be that you could get to the ground and get out of the plane before the cabin is involved.

 

If you need to do the descent because you heard a bang and there is a hole in the top of the cowling, and maybe the engine froze up, you have an engine failure but are not in the fire-critical situation.  Then it would be pitch for best glide, locate the best field (remember the Nearest function on the GPS), and do your checklist for restart, failing that engine off landing. 

 

However, there are many other circumstances where resourcefulness is the best option.  My one emergency descent in anger was on a trip overflying Lake Michigan west to east at 19K.  We had a most excellent 75 knot+ tailwind, yielding around 240 knots ground speed.  Shortly after passing Lake Michigan, and about to enter the back side of a front (IMC) we had a critial loss of oil pressure.  ATC advised that the best airport was London, ON, about 20 miles to starboard and perpendicular to our flightpath.  The manual says to expect eminent engine seizure.  My analysis was that I wanted to keep the engine with us for as long as possible, in the event I needed it to reach the runway. I also needed to get down fast because the great tailwind would blow us over Lake Erie if I did not.  So I throttled back, deployed the speedbrakes to prevent exceeding Vne, and made a rapid but not quite Vne dive towards London, which we had glimpsed before being blown into the IMC.  About 7k of the descent was through IMC with the VSI pegged, so I do not know the descent rate, just that it was fast.  For those not familiar with turbo ops, a descent from 19k is normally quite long, it would take 35 or 40 minutes and needs to be started quite a ways out, anywhere from 80 to 120 nm depending on winds.  In our circumstances, I could not afford a conservative rate.  When we broke out, we immediately spotted the runway because the crash trucks were at the approach end with their emergency lights on showing the way.  I aimed short of the runway, flared to drop the excess speed, dropped the gear, took in the speedbrakes, and squeaked the landing.  Oil all over the belly, we had lost 5 of 7 1/2 qts.  I may have used the engine at the end, I honestly don't remember that part.  At any rate, the engine survived as did we.

 

I happened to be on my way to a Mooney PPP, and when we finally got there the instructor taught me the steep spiral.  He said, "there, now you know what to do if you need to get down quickly."  I told him thank you, but I was very happy with my decisions given the conditions, and would not change a thing.  Given the tailwinds and the rapidly approaching Lake Erie, I would not have chosen a steep spiral, at least not until I was much lower down, out of the very strong winds aloft, and over the airport.

 

The moral is, know all your options and understand your circumstances.  No single answer fits all types of emergencies.  I guess the other thing to say is that when an emergency happens, if you are well trained (and I hope that I was/am by my instructors), my personal experience was that you do not stop and spend time being nervous.  You certainly do think the situation through so you understand your options, but it is a major advantage if you have assessed them ahead of time, in training or in a discussion like this.  The training kicks in, you make decisions, you trust that they are good ones, and you execute.  You should constantly evaluate the result and adjust, but not to the point of getting the thought process in the way of the execution, because at the end of it properly flying the airplane is what is going to save your passengers and you, and dealing with whatever landing conditions that you have and not freezing up because there was a different decision you could have made at some point and didn't, and you focus on what you wish you had done rather than what you have in front of you, is not something there is time for.  Get trained well.  Decide and do. 

[jetdriven]

rob, on 23 Oct 2013 - 10:33 PM, said:

 

 

This really brings up a critical point. 4,000-6,000 fpm is great practice. But control is critical. You want to arrive straight in or 1,000 abeam without your ear drums blown and enough wits about you to get it on the ground.

You smell smoke and the area by your feet is getting really hot. You have between 90-120 seconds before you are going to be burned alive. What do you do?

[aviatoreb]

Flaps add more drag (and lift) but you have to fly at a lower airspeed to use them. The airplane is closer to best glide speed at the top of the white arc, you are really only 20 knots above it. . Drag rises to the square root of the airspeed, however, and the extra 20-25 knots (and really you can go a lot faster) by flying gear down and flaps up will be a greater FPM descent. Exceed the flap speed and you can cause structural failure of the airplane. Exceed gear down speed (we are talking real emergency here) and you damage the gear doors, but the descent rate is pretty breathtaking. Try it both ways and report back.

 

If a structural failure of the flaps means the wing becoming damaged then that is scary.  If it is minor damage to the flaps due to exceeding Vf - then that is expensive and bad but if the airplane is on fire - why do I care?  After all damage to the gear doors is considered structural failure due to exceeding Vle.  Or is damage due to exceeding Vf possibly more serious?

 

I have only recently begun thinking about fastest possible decent since I recently started training for a commercial, that included emergency decent procedure.  In practice, I do not want my plane to break in any way, so I will not exceed gear speed or any V-speed that I might be willing to do if there was a real emergency.  Even with gear down at 132IAS (my gear speed), and spiraling, and speed brakes out, she decends VERY fast.

 

But I don't want to make up procedures here - surely there is an FAA approved and suggested way to react to such an emergency.  Is it indeed exceed Vle but do not exceed Vf?

[aviatoreb]

You smell smoke and the area by your feet is getting really hot. You have between 90-120 seconds before you are going to be burned alive. What do you do?

 

Did anyone here mention to pull the red knob (kill the engine) push the blue knob (increase pitch to add prop-drag) and turn fuel switch to off?

 

Amongst get down asap.

 

I am really surprised and disappointed in myself .... that I never thought of any of this stuff until about a month ago when I started reading for commercial.  In PPL training the emphasis seems to be on extending glide range in case of engine out as the primary emergency to worry about.

 

Separate and related - last year I purchased a smoke hood that I keep in arms reach on the floor.  Some failure modes of fire, or electric failure could cause lots of smoke and blind and choke but not be an open fire...but still extremely dangerous, esp if you cannot even see the instrument panel inside the plane.

[jlunseth]

Did anyone here mention to pull the red knob (kill the engine) push the blue knob (increase pitch to add prop-drag) and turn fuel switch to off?

 

Yes, also leave the mags on to burn any fuel in the lines through normal combustion, rather than leaving it for the fire to find and use.  Don't know that the prop knob is that important.  My choice is Vne, and whatever it would take to get to Vne you do, if the prop is too much drag to get there you would pull it rather than push.  Would not quarrel with the slower gear deployed descent if someone else made that choice, it would not be my choice in the event of an engine fire.

 

"But I don't want to make up procedures here - surely there is an FAA approved and suggested way to react to such an emergency. Is it indeed exceed Vle but do not exceed Vf?"

I don't believe the FAA recommends a specific procedure, they would leave that to the manufacturer.  They teach the spiral descent in commercial (I have heard of people who have learned it elsewhere), but the choice of method to deal with an emergency is yours as  PIC.  And no, the FAA does not restrict a fire emergency descent, or any other emergency descent to Vle or Vflaps.

 

I would like to add one note here, if anyone does out to actually practice these maneuvers, you need to watch your engine temps and read your POH first.  In my case, more than one spiral will supercool the engine if it is at idle, the CHTs I have seen are in the mid-high 100's (like 175F).  My manual also says not to exceed 20" MP until the temps warm to 250F.  20" is very low in a turbo, and may or may not provide level flight.  The POH also says that if oil temps drop below 100, operation at higher MP's may cause loss of oil pressure.  So three points.  First you may not be able to execute a standard go around, you may need to fly straight and level or in a descent at the end of the maneuver, until the engine warms, so you need more altitude than just what would be necessary for the practice emergency descent.  Second, by all means practice, but read your manual before you just go do it, so you don't hurt your engine and yourself.  Third, I don't do these anywhere except over an airport, just in case the engine gets truly unhappy for some reason.