emergency decent

[contrail]

I was climbing through FL230 when I had a decompression, I declared an emergency and made an emergency decent. I returned to the
airport landed safety and found it was due to a window cracked. However even though I got credited for bringing the aircraft in safety I lost
a lot of points due to the decent. I don't understand this I thought getting the aircraft down as quickly as possible would have been the
object here obviously within the aircrafts capibilites i didn't do a nose dive or turn the plane into a missile I only put it in an attitude steeper
than normal so whats wrong here?

[pdjpeter]

the reason (i'm guessing) is that if u decended quikly u must of used quite alot of downward bank which would create g forces which
would lose u ponits

[Travis]

You're lucky...you only had it at FL320...it's really fun trying to bring her down from FL680...



Post Edited ( 12-11-05 03:03 )

[AeroJim]

what were u flyin way up there

[Travis]

I was flying the C4 SST (a fictional aircraft I found on avsim). It's supposed to use two of the Concorde's engines to carry 10 pax and 4 crew 8000+nm
at M2.0 (though you can get it up to ~M2.49 without getting an overspeed warning...wonderful if you find yourself running a few minutes late).

[SWAFO]

Interesting!

There are specific procedures for emergency descent. The descent can't be done at -20,000FT/min for example. You should be able to
descend between -5000 and -7000ft/min (depending on the conditions, and aircraft, etc.). Let me know if you've got any more questions.

[lightrail]

I read somewhere that oxygen masks are useless above FL300 as the air pressure would be too low to force the air molecules into your lungs. so SSTs
have to drop to at least FL300 so passengers can breath oxygen from the masks. Is this true?

[olseric]

I don't understand this I thought getting the aircraft down as quickly as possible would have been the
object here obviously within the aircrafts capibilites i didn't do a nose dive or turn the plane into a missile I only put it in an attitude steeper
than normal so whats wrong here?

An emergency descent has a different configuration of the aircraft as opposed to a normal "nose down" descent.

A general overview:

1. Slow the plane down by reducing the throttles and extending the speed brakes.
2. As the aircraft slows, it will naturally start to descend.
3. Now, maintain attitude (don't let your nose dip). If you're not descending fast enough, bleed speed with the flaps.

In theory, it's the same sort of concept as an approach to a runway. If you want to increase your rate of descent, what do you do? You
back off the throttle, right?

If you do this right, as Brad said, 7000 fpm easy with the 737.

[SWAFO]

Thanks for the extra tips Eric! Was in a hurry to get to bed last night. Bears lost yesterday, so that threw off my whole day!


Keep in mind that some aircraft have a maximum altitude limitation for flap extensions (if required to slow speed). Other than that,
everything Eric mentioned is right. This must be done in a timely fashion though. You don't have 5 minutes to sit around at FL410
bleeding off speed for a descent. Depending on conditions, a regular "nose down" descent may be acceptable.

[Ham]

I was taught a slightly different procedure: In the Airbus (I can't speak for the 737, that's Brad's job), the PF (usually the Cpt. takes over
command immediately) turns in 10'000 or MSA, whichever is higher, and than pulls all three knobs, which gives us direct control over the
A/P. Than he turns in Mmo/Vmo and makes a 30° to the right to get off the Airway. PNF handles all non-flying stuff e.g.: reading through
the checklist, starting the stopwatch, informing ATC, informing FAs etc.
What I want to say is that we will actually not reduce speed but start a LVL/CHG at the HIGHEST possible speed. This gives us the
highest rate of descent possible (just in the range Brad mentioned, 5-7'000/min should bring any "normal" airliner to a safe altitude in 5-7
minutes). Pitch depends on varios factors, such as GW, CG,..., but shouldn't excess -15 in normal circumstances.
For manual flying: Bring thrust to idle, and maintain highest possible speed by adjusting pitch.

I don't see a benefit by reducing speed, so you might explain that to me, Brad, won't you?
Anyway, I would like to thank you all for creating this forum, it's the best forum for the MSFS I have found yet, with great moderators.
And I would like to thank Dan for his work. The best €30.- (CD boxed version) I ever invested in a FS-add-on!!!

[SWAFO]

Reducing speed is done for a number of reasons. If I'm descending at such a rate as required in an emergency descent, the aircraft is
going to accelerate beyond VMO, if I haven't decelerated in the first place. In an emergency descent, it is expected that VMO may be
exceeded, however all precautions to not exceed it are taken.

Plus, who wants to be coming into the terminal area at 350KIAS? I'm not in the Marines anymore!


There are some other procedural issues to follow, however because of the rarity of this event, I don't feel I need to type a 3 page post!

[Medic_Pilot]

I have been taught at Flight Safety both methods, but we prefer to do our emergency descents like this:

Chop throttles and extend spoilers to slow below safe gear and flap speed. Extend gear and flaps when able, then enter a descending
turn of approximately 30 degrees while maintaining maximum gear or flap speed (ours is the same).

This turns in an acceptable descent rate while keeping the airplane at a speed that is not approaching VMO or VMC.

Greg

[SWAFO]

Very true!

[Ryanamur]

Plus, who wants to be coming into the terminal area at 350KIAS? I'm not in the Marines anymore!

Oh come on! You know how it goes, "once a Marine, always a Marine!"

Phil

[SWAFO]

Believe me, I'm the number one advocate of that point!!