DC-4 crash Alaska

[slacktide]

Originally Posted by RichardJones

A stall in a turn is an incepit spin. No chance of walking away from that.

That's not really true. A stall in an uncoordinated turn is an incipent spin. A stall in a coordinated turn is called an accelerated stall, I do them all the time, they are not a big deal but are very useful for beating the concept that there is no such thing as a stall speed into the head of excessively 2-dimensional students.

[NoelEvans]

Originally Posted by RichardJones

A stall in a turn is an incepit spin.

No it is not! A stall in a turn when balanced is just a stall. A stall when not balanced, in level flight or in a turn, can lead to an incipient spin.

Either your instructor didn't teach you well or you weren't paying proper attention.​​​​​​

I hope that slacktide and I are teaching a bit better!!

[Speed_Trim_Fail]

Originally Posted by NoelEvans

No it is not! A stall in a turn when balanced is just a stall. A stall when not balanced, in level flight or in a turn, can lead to an incipient spin.

Either your instructor didn't teach you well or you weren't paying proper attention.​​​​​​

I hope that slacktide and I are teaching a bit better!!

With apologies for the drift, but for any newer students this is precisely why it is so so important to learn to keep the ball centred and (I was told many moons ago anyway) why the base to final stall recovery is taught; if one overshoots the extended centerline a temptation is to squeeze rudder to tighten the turn, but to try and avoid over banking using opposite aileron. This puts you in a low energy state, cross controlled, with an increased load factor and in all likelihood flaps out too…

That said I’ve been so thoroughly airbussed at this point in my life that I suspect my own performance would warrant limiting my GA to an Ercoupe should I ever return to an SEP

[421dog]

Originally Posted by B2N2

Vmc exists by the grace of asymmetric thrust, if there is none then Vmc doesn’t become zero, it ceases to exist.
There may still be asymmetric drag for a myriad of reasons ( windmilling vs feather) but that’s not Vmc.

If you sense a loss of control take away the asymmetric thrust. It’s better to have a controlled off airport landing then a Vmc loss of directional control.
Reduce power on the ‘working’ side to regain control, this can mean reducing power on just the outboard or on both.If that engine explosion destroyed hydraulic lines and flight control rods or cables and pulleys then they may have lost all roll control.

Have had a couple of misadventures and this is true.
If the aircraft is flying ex-engines, it will keep flying until it runs out of airspeed/altitude (if it still has wings).

without those, you’’ll likely need a better pilot than me (or an in with mssrs
Martin and Baker)

[RichardJones]

Originally Posted by NoelEvans

No it is not! A stall in a turn when balanced is just a stall. A stall when not balanced, in level flight or in a turn, can lead to an incipient spin.

Either your instructor didn't teach you well or you weren't paying proper attention.​​​​​​

I hope that slacktide and I are teaching a bit better!!

Hang on a moment. Is an aircraft ever in perfect balance? I say no. So a stalled aircraft, depending on type is in danger of entering a spin, as it will be out of balance.

[EXDAC]

ref: AC 61-57C:

110. TYPES OF SPINS.
a. An incipient spin is that portion of a spin from the time the airplane stalls and rotation starts, until the spin becomes fully developed. Incipient spins that are not allowed to develop into a steady state spin are commonly used as an introduction to spin training and recovery techniques.
b. A fully developed, steady state spin occurs when the aircraft angular rotation rate, airspeed, and vertical speed are stabilized from turn-to-turn in a flightpath that is close to vertical.

There are many other sources that define "incipient spin" but I found none for which rotation is not a necessary condition. Rotation does not necessarily follow stall and wing drop.

[VH-MLE]

Defining an incipient spin among pilots is a bit like asking 10 different lawyers the same question & you'll get 15 different answers! . Even theory of flight books & aircraft manufacturers cannot agree on what exactly constitutes an incipient spin. I think EXDAC's reference is correct.

There are a variety of reasons that can cause a wing to "drop" at the point of stall i.e a wing drop stall occurs. Autorotation i.e. will develop if opposite rudder is not immediately applied to prevent (further) yaw in the direction of the dropped wing. Contrary to what a number instructors incorrectly teach their students, opposite rudder is NOT applied to raise the dropped wing, but as I said to prevent further yaw...

Apologies for the "off thread" comments & once again, the above is my 2 lire's worth...

[blind pew]

It isn’t true that autorotation will develop with a wing drop at the stall; it depends on aircraft type, what causes the wing drop and control position at wing drop. - from experience.

[NoelEvans]

Agreed.

A wing drop on a C152 or a PA28 is far, far, far less likely to lead to autorotation than a wing drop on a Harvard - from experience.

[DogTailRed2]

If fuel vapour had built up in the engine area or wing and the engine fire ignited this vapour causing a small explosion couldn't that damage the aircraft sufficiently that any recovery was impossible?
Everyone seems to be suggesting that the accident was recoverable. Not possible to determine from the footage. As the aircraft crashed we have to assume it wasn't?

[sablatnic]

Originally Posted by DogTailRed2

If fuel vapour had built up in the engine area or wing and the engine fire ignited this vapour causing a small explosion couldn't that damage the aircraft sufficiently that any recovery was impossible?
Everyone seems to be suggesting that the accident was recoverable. Not possible to determine from the footage. As the aircraft crashed we have to assume it wasn't?

If you look at the leading edge both sides of the missing #1 engine, the leading edge looks slightly deformed, as if the d-box was blown open by the explosion. Images aren't clear enough for a certain diagnose though.

[Liffy 1M]

Preliminary Report by NTSB: Report

[Mr Albert Ross]

Ouch!!

With an engine coming off it appears serious enough that it had most likely become unflyable.

[Cedrik]

Typical prune thread, all the armchair experts arguing pedantic points. A couple of experienced pilots couldn't handle a catastrophic explosion obviously taking out controls but because somebody stalled a Cherokee once and survived they know better.

[punkalouver]

An interesting report here about a DC-4 fire that did not result in a crash(Just an overrun). The importance of shutting off fuel and reporting fuel pressure fluctuations and compliance with AD's are mentioned.

Aviation Investigation Report A06W0002 - Transportation Safety Board of Canada (bst-tsb.gc.ca)

Accident Douglas C-54G (DC-4) C-GXKN, (aviation-safety.net)

[Avman]

Originally Posted by Cedrik

Typical prune thread, all the armchair experts arguing pedantic points. A couple of experienced pilots couldn't handle a catastrophic explosion obviously taking out controls but because somebody stalled a Cherokee once and survived they know better.

Bang on Cedrik. The crew were experienced C-54 pilots and took all the required actions which may, for reasons not yet known, not have prevented the fire from spreading. Once that engine blew (and possibly took out some vital components) they were passengers for those last few tragic seconds. Some of the "technical" aspects discussed above just make me cringe!

[NoelEvans]

Originally Posted by Cedrik

Typical prune thread, all the armchair experts arguing pedantic points. A couple of experienced pilots couldn't handle a catastrophic explosion obviously taking out controls but because somebody stalled a Cherokee once and survived they know better.

Originally Posted by Avman

Bang on Cedrik. The crew were experienced C-54 pilots and took all the required actions which may, for reasons not yet known, not have prevented the fire from spreading. Once that engine blew (and possibly took out some vital components) they were passengers for those last few tragic seconds. Some of the "technical" aspects discussed above just make me cringe!

Agreed!

"Incipient spins" was entirely Off Topic! (But being Off Topic, still needed correcting.)

An engine coming off an aeroplane like that is very, very serious and very likely to lead to uncontrollability.

(I wonder how many of those 'armchair experts' on here have ever flown in a DC4, even as pax??!)

[EXDAC]

Originally Posted by NoelEvans

An engine coming off an aeroplane like that is very, very serious and very likely to lead to uncontrollability.

It is clear from the surveillance video that control was lost long before the engine departed. That's not just my conclusion. NTSB prelim says "The No. 1 engine separated from the wing about 100 ft above the ground and eventually came to rest on the frozen Tanana River."

[NoelEvans]

Sorry, I should have said:

Events leading to an engine coming off an aeroplane like that is very, very serious and very likely to lead to uncontrollability.

The engine actually coming off was 'later down the line'.

I was trying to emphasise that the causes for an engine coming off an aeroplane like that (rather than say a B737) would be very, very serious and very likely lead to uncontrollability.

[EXDAC]

Another C-54 in flight engine fire report here - https://tinyurl.com/w74s3p8y