PTS emergency descent...how?

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jconway2002

Pre-takeoff checklist
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jconway2002
I had the oral portion of my checkride Saturday, but the flying portion was postponed due to weather. The examiner seems like a by the book sort of guy, and mentioned that he cant give second chances on the checkride. He told me a few things I can expect, and one of them was emergency descents. The PTS doesn't really give specifics, and the POH for my Cessna 152 doesn't list emergency descent anywhere, the closest thing to that listed is engine fire in flight or an emergency descent through clouds.

I have seen videos on emergency descents and they describe doing the following:
  • Throttle to idle
  • full flaps
  • make a 45 degree descending turn at Vfe

engine fire in flight:
  • mixture to idle cutoff
  • fuel valve off
  • master off
  • cabin heat and vents closed
  • airspeed 85 KIAS

emergency descent through clouds:
  • mixture full rich
  • carb heat on
  • reduce power to 500-800 ft/ min descent
  • trim to establish 70 KIAS

So which one should I use? :confused:
 
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for my checkride prep, my CFI had me do emergency full slips.

For my checkride the examiner asked scenarios and asked what technique would I use and why. I don't recall if I had to demonstrate emergency slip, but he did have me slip to land once.
 
jconway2002 said:
I had the oral portion of my checkride Saturday, but the flying portion was postponed due to weather. The examiner seems like a by the book sort of guy, and mentioned that he cant give second chances on the checkride. He told me a few things I can expect, and one of them was emergency descents. The PTS doesn't really give specifics, and the POH for my Cessna 152 doesn't list emergency descent anywhere, the closest thing to that listed is engine fire in flight or an emergency descent through clouds.

I have seen videos on emergency descents and they describe doing the following:
  • Throttle to idle
  • full flaps
  • make a 45 degree descending turn at Vfe

engine fire in flight:
  • mixture to idle cutoff
  • fuel valve off
  • master off
  • cabin heat and vents closed
  • airspeed 85 KIAS

emergency descent through clouds:
  • mixture full rich
  • carb heat on
  • reduce power to 500-800 ft/ min descent
  • trim to establish 70 KIAS

So which one should I use? :confused:
Click to expand...

Most likely going to be the fire scenario. The turning emergency descent spiral is for commercial.
 
I can't remember doing emergency descents on my initial ppl, ASEL, but I definitely remember doing them on the seminole for AMEL.

What I remember is:
Mixture/props full forward
Throttles Idle
Gear down (stability?)
Cowl flaps closed
Dive at max gear down airspeed
While diving, do shallow s turns to watch for traffic.

It's been so long I don't remember exactly, but the goal was to lose altitude as quick as possible. What I said above might be very wrong from what Iremember, so take with a grain of salt.
 
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Cherokees and Skyhawks are so square cross-sectionally [is that a word?] that they are really hard to hold in hard slip . . . they don't like flying sideways . . . but if you insist they will!
 
steingar said:
There was the time I did this. In a subsequent thread a number of "experts" declared it impossible.
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Puhleez...this again? I offered you $100 before to get video of exactly what you describe. How about I up it to $200...or you can admit that you are severely mistaken about the numbers you describe, and the descent angle they would necessitate. Based on what you continue to claim, this is what your descent angle would have looked like - see link below (post #70). It just ain't gonna happen without a hurricane wind on your nose.

How many Cherokee pilots do we have here? A bunch I'd guess. Anyone else want to make a couple hundred bucks since Steingar can't come up with video of this? If Steingar can do it, anybody else should too.

http://www.pilotsofamerica.com/forum/showthread.php?p=878437#post878437
 
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write-stuff said:
Here's the latest from the updated PHAK about emergency descents:

http://www.faa-ground-school.com/library/emergency-descents.pdf
Click to expand...

Better than anything officially stated on the topic so far, but still not conclusive. The FAA seems intent on saying "follow the POH" without giving any specific instructions in the absence of POH guidance. And I've never seen any guidance in the POH for a single engine piston trainer-class plane.

The two methods are to go dirty at Vfe, or to go clean at Vne. There has been no specific guidance ever on which option is better.

I'd personally pick the Vfe version, I think, because the plane will be going slower and it will be easier to keep in front of the plane than if I'm hurtling towards the earth at 160KIAS.
 
Agreed. Vfe in a real steep turn. Keep the wing unloaded. You need to land at the bottom, you don't want the speed.
 
I just slipped. I figure if I need to get down fast, a slip will do just that. The DPE said "My ears hurt. This is good."
 
Alexb2000 said:
Agreed. Vfe in a real steep turn. Keep the wing unloaded. You need to land at the bottom, you don't want the speed.
Click to expand...

There's the "safe", "PTS" way for the lowest-common-denominator type of pilot, and then there's the most effective way. If I was on fire and minutes from dying, I'd much prefer to get my butt on the ground ASAP. You'll come down much faster at a 70 degree bank at Vne. The time you'd save compared to descending at a 45 deg bank at Vfe would be a lot more than the 4 seconds it takes to get from Vne to 1.3Vso at the bottom by doing a tight level turn.
 
RoscoeT said:
Puhleez...this again? I offered you $100 before to get video of exactly what you describe. How about I up it to $200...or you can admit that you are severely mistaken about the numbers you describe, and the descent angle they would necessitate. Based on what you continue to claim, this is what your descent angle would have looked like - see link below (post #70). It just ain't gonna happen without a hurricane wind on your nose.

How many Cherokee pilots do we have here? A bunch I'd guess. Anyone else want to make a couple hundred bucks since Steingar can't come up with video of this? If Steingar can do it, anybody else should too.
Click to expand...

Sorry, I don't carry video cameras to document my whole damn life. Maybe we'll give it a go at a POA fly in sometime. But I stand by what I said. Perhaps you might try it yourself some time? You might be surprised.
 
Post #70???? Steingar, what cut/paste madness do you have going on???
 
If you're using the Vfe method, which one do you use? My first flaps are 140, the next ones are at 90.
 
steingar said:
Sorry, I don't carry video cameras to document my whole damn life. Maybe we'll give it a go at a POA fly in sometime. But I stand by what I said. Perhaps you might try it yourself some time? You might be surprised.
Click to expand...

You realize that's a less than a 1:1 glide ratio right?
 
steingar said:
Sorry, I don't carry video cameras to document my whole damn life. Maybe we'll give it a go at a POA fly in sometime. But I stand by what I said. Perhaps you might try it yourself some time? You might be surprised.
Click to expand...

You stand by a 58 degree descent angle in a stablized slip in a Cherokee? That's the angle produced when you drop 8000' in a 5000' horizontal distance...but if your horizontal distance was actually 6+ miles, then I'd buy your story.

And I have tried it. The best angle I've ever gotten out of an aerobatic airplane I used to fly that slips a whole lot better than a Cherokee (I've slipped a Cherokee) is about half that.

Surely with all the GoPro's and Cherokees out there that somebody could easily shoot some video of this massive descent angle. Fly final at 1000' AGL until you get about 700' from the end of the runway. Then throw in your super slip and show the numbers staying still in the windscreen without picking up airspeed.

Any takers? Anybody want to back up Steingar's impossible claim? $200 to anyone who can video this in a Cherokee without a hurricane headwind.
 
comanchepilot said:
Cherokees and Skyhawks are so square cross-sectionally [is that a word?] that they are really hard to hold in hard slip . . . they don't like flying sideways . . . but if you insist they will!
Click to expand...

Is that what it is? I thought it was just me:lol:.

When I did my TW training last year in the Super D, I found out what a "real" slip felt and looked like:yes:

god I love that plane!!!

During my first slip in it, the CFI had to tell me twice "stand on the right rudder". I think I was so used to the rudder authority of the Skyhawk, I hadn't yet realized...this ain't no damn skyhawk:rofl:
 
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Let's assume for a second our Columbus based friend did actually do what he said what he did. He dropped 8,000 feet over 5,000 feet. Ok, so lets do the math. Safe descent speed in a Cherokee being slipped is probably about 60mph forward speed as not to stall, so it took him a minute to cover that 5,000. That results in an 8,000fpm decent. That's a vertical speed of 96mph.

a 20mph headwind would make it a 5300fpm descent.

Discuss amongst yourselves.
 
EdFred said:
Let's assume for a second our Columbus based friend did actually do what he said what he did. He dropped 8,000 feet over 5,000 feet. Ok, so lets do the math. Safe descent speed in a Cherokee being slipped is probably about 60mph forward speed as not to stall, so it took him a minute to cover that 5,000. That results in an 8,000fpm decent. That's a vertical speed of 96mph.

a 20mph headwind would make it a 5300fpm descent.

Discuss amongst yourselves.
Click to expand...

Steingar's Cherokee has the STC for going into shuttlecock mode like Space Ship One. :D
 
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RoscoeT said:
There's the "safe", "PTS" way for the lowest-common-denominator type of pilot, and then there's the most effective way. If I was on fire and minutes from dying, I'd much prefer to get my butt on the ground ASAP. You'll come down much faster at a 70 degree bank at Vne. The time you'd save compared to descending at a 45 deg bank at Vfe would be a lot more than the 4 seconds it takes to get from Vne to 1.3Vso at the bottom by doing a tight level turn.
Click to expand...

Remember, the OP is a very new pilot, taking his checkride. The goal is a procedure to lose altitude ASAP and land the plane somehow where he won't die or get seriously injured.
 
EdFred said:
Let's assume for a second our Columbus based friend did actually do what he said what he did. He dropped 8,000 feet over 5,000 feet. Ok, so lets do the math. Safe descent speed in a Cherokee being slipped is probably about 60mph forward speed as not to stall, so it took him a minute to cover that 5,000. That results in an 8,000fpm decent. That's a vertical speed of 96mph.

a 20mph headwind would make it a 5300fpm descent.

Discuss amongst yourselves.
Click to expand...

The most I've ever done (with CFI onboard) was 2000 fpm spiral descent. Don't remember the bank angle, but it got me down fast and very easy to level off and land.
 
I took the ASEL checkride back in Sept of last year. We discussed emergencies and the decent during the oral portion. I did not have to demonstrate it in the air, but my "emergency" was an engine out. I completed the checklist and found a field to land in, and that was it.
 
My Sierra has an Emergency Descent section in the POH, albeit it doesn't seem to be terribly intricate:

1. Propeller - Full Forward Position
2. Throttle - Idle
3. Landing Gear - Down
4. Airspeed - Establish 155 mph
 
livitup said:
The two methods are to go dirty at Vfe, or to go clean at Vne. There has been no specific guidance ever on which option is better.

I'd personally pick the Vfe version....
Click to expand...

Was taught Vfe tight turns method for emergency decent and the Vne for fire (I guess to try and put it out). DPE asked "why?" and wanted to hear something that sounded somewhat rational. I think if you tell them that there is nothing in the POH checklist for that plane, and this is the reason for type 1 and type 2 you should be ok (converting 2 to 1 for landing). The BEST recommendation was to ask your CFI as he will know what the examiner wants to see.
 
When I covered it with the DPE, it was the fire scenario. Followed the C152 POH, started the descent he said "looks great but the fire is still going, what are you gonna do?" That is when you switch from descend hastily to get this plane down now. Throw in the 45-60 deg bank, nose down and aim for but do not exceed Vne.
 
danhagan said:
Was taught Vfe tight turns method for emergency decent and the Vne for fire (I guess to try and put it out).
Click to expand...

To get on the ground as quickly as possible. Aluminum doesn't tolerate heat very well. Get down. Get out.
 
The PTS is not a teaching document, it is a testing document. Look to the Airplane Flying Handbook to learn how the examiner wants you to perform this maneuver.

Bob Gardner
 
This came up on here a little while ago, I think? The most conclusive answer I have been able to come up with is, of course, "it depends." Basically, if you're high (at cruising altitude, more or less), you want to spiral it in clean at Vne and a 60+ degree bank. If you're low, you want to use full flaps and do a spiral at 60+ degrees of bank at Vfe. The "break even" altitude depends on the plane.

A bit of anecdotal evidence. I fly mainly Tecnam Eaglets, and on my private checkride, I did the Vne spiral. The examiner, who had never seen emergency descents in the Eaglets, said that what I did was perfectly acceptable, but asked if for his own sanity he could try out the full flaps Vfe spiral method from the AFM. I pegged the VSI when I did my descent, but if I recall correctly, he only got it to about 1200 fpm. If you're up high, a pegged VSI is going to get you down and stopped on the ground faster than 1200 fpm. However, if you're particularly close to the ground, the time it takes to slow down might increase the total time it takes for you to get on the ground. Where exactly this break even altitude is, I can't figure out, because I don't know off the top of my head how long it takes for the airplane to slow down.
 
bobmrg said:
The PTS is not a teaching document, it is a testing document. Look to the Airplane Flying Handbook to learn how the examiner wants you to perform this maneuver.

Bob Gardner
Click to expand...

From the AFH:

EMERGENCY DESCENTS
An emergency descent is a maneuver for descending
as rapidly as possible to a lower altitude or to the
ground for an emergency landing. [Figure 16-6] The
need for this maneuver may result from an uncontrollable
fire, a sudden loss of cabin pressurization, or any
other situation demanding an immediate and rapid
descent. The objective is to descend the airplane as
soon and as rapidly as possible, within the structural
limitations of the airplane. Simulated emergency
descents should be made in a turn to check for other air
traffic below and to look around for a possible
emergency landing area. A radio call announcing
descent intentions may be appropriate to alert other
aircraft in the area. When initiating the descent, a bank
of approximately 30 to 45° should be established to
maintain positive load factors (“G” forces) on the
airplane.

Emergency descent training should be performed as
recommended by the manufacturer, including the configuration
and airspeeds. Except when prohibited by
the manufacturer, the power should be reduced to idle,
and the propeller control (if equipped) should be
placed in the low pitch (or high revolutions per minute
(r.p.m.)) position. This will allow the propeller to act
as an aerodynamic brake to help prevent an excessive
airspeed buildup during the descent. The landing gear
and flaps should be extended as recommended by the
manufacturer. This will provide maximum drag so that
the descent can be made as rapidly as possible, without
excessive airspeed. The pilot should not allow the
airplane’s airspeed to pass the never-exceed speed
(VNE), the maximum landing gear extended speed
(VLE), or the maximum flap extended speed (VFE), as
applicable. In the case of an engine fire, a high
airspeed descent could blow out the fire. However, the
weakening of the airplane structure is a major concern
and descent at low airspeed would place less stress on
the airplane. If the descent is conducted in turbulent
conditions, the pilot must also comply with the design
maneuvering speed (VA) limitations. The descent
should be made at the maximum allowable airspeed
consistent with the procedure used. This will provide
increased drag and therefore the loss of altitude as
quickly as possible. The recovery from an emergency
descent should be initiated at a high enough altitude to
ensure a safe recovery back to level flight or a
precautionary landing.
When the descent is established and stabilized during
training and practice, the descent should be terminated.
 
jpower said:
The most conclusive answer I have been able to come up with is, of course, "it depends." Basically, if you're high (at cruising altitude, more or less), you want to spiral it in clean at Vne and a 60+ degree bank. If you're low, you want to use full flaps and do a spiral at 60+ degrees of bank at Vfe. The "break even" altitude depends on the plane.
Click to expand...
I'm trying to understand this as an energy management problem and I don't understand what the 'break even' means. Doesn't one configuration shed energy faster than the other regardless of initial altitude?

Is it about getting back down to an appropriate landing speed at the end of the maneuver?
 
tiger said:
I'm trying to understand this as an energy management problem and I don't understand what the 'break even' means. Doesn't one configuration shed energy faster than the other regardless of initial altitude?

Is it about getting back down to an appropriate landing speed at the end of the maneuver?
Click to expand...

It's all about getting us down to an appropriate landing speed. Maybe not on the practical test, though my examiner said something like "your engine has failed and is on fire. Get me down."

The "break even" point would be where the two methods get the plane from altitude to landing speed and configuration in the same amount of time. If you're cruising at 8000 ft agl and descending at Vne at 2500 fpm (let's just say), you'll get from 8200 to 200 agl in about 3.1 minutes. Then, slowing it down, configuring for landing, and lining up with your landing site takes another 30 seconds (this is a wild guess and probably a bit low, but we'll go with it just for the sake of argument) and you're up to 3.6 minutes. Descending at 1200 fpm (flaps out, spiral at Vfe) gives you 6.5 minutes to 200 agl, and you're already in landing configuration.

Now, let's say you're at pattern altitude, so 1000 agl. To get down to 200 agl, it takes about 0.3 minutes doing the Vne spiral, and slowing down and lining up takes us to 0.8 minutes. Descending at Vfe gives us roughly 0.7 minutes.

I don't know how long it takes to get an airplane slowed down, but regardless, in the majority of cases, the Vne spiral will get you down and ready to land faster, but if you're close enough to the ground, you're better off with a Vfe spiral.

Now of course, some airplanes will behave differently aerodynamically. You would have to see what sort of vertical speeds you get with the Vne spiral and the Vfe spiral and determine for yourself the break even point for your airplane.
 
On the reverse, once I understood why there was a Vx and Vy, it made this concept intuitive.
 
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