King Air is a strong plane (video)

[cpxxx]

Lucky escape, but the Super King Air is a strong aircraft. There's one parked round the back of the hangar at the airport I fly out of. I'm not sure what happened but I think the pilot became disorientated in IMC and entered the usual spiral dive, then went VMC and pulled hard. The aeroplane looks OK until you get get close and see all kinds of funny angles. It will never fly again.

Interesting comment in the NTSB report about the oxygen working normally. Wonder if there is more to the story?

[eskimo2]

Anyone have an idea of what the max speed rating of this plane is and what it may have gone up to?

[eagl]

According to that report, they first dumped pressure and then donned O2 masks.  If I recall my training correctly, at 27,000 ft the time of useful consciousness can be as low as 30 seconds and significant impairment can occur almost immediately, so it is very possible they were already hypoxic and unable to accomplish the oxygen procedures within seconds of dumping cabin pressure.

I also suspect that as they awoke, one of them pulled back on the controls before being alert enough to properly assess attitude and airspeed, so they may have ripped the tail off themselves.  The failure pattern (ripped off stab and wingtips bent up) don't look to me like a "simple" overspeed.

None of this is particularly unusual or unexpected during or after a hypoxia event, except the fact that they survived.  The expected result from a chain of events like this is death.  Getting on oxygen immediately and if possible BEFORE dumping cabin pressure is absolutely critical, as is descending immediately.

Also of note is that pressure breathing is required above around 25,000 ft otherwise your lungs will not absorb enough oxygen.  So even if there was plenty of unpressurized oxygen flow when they donned the masks, a bad mask seal or a delay in descending to a lower altitude could have still resulted in hypoxia and unconsciousness.  This is why unpressurized military aircraft are limited to 25,000 ft and below.  Pressure breathing is not comfortable even when properly trained on a recurring basis.

[RAIDER14]

Originally posted by john9001
good thing they did not have auto pilot on, they would be dead.  that happened to a small plane few years ago, the plane flew until it ran out of fuel.

Payne Stewart's final flight

[Casca]

They were lucky to gather that in.  Under FAR 23 pressure breathing apparatus is only required if the aircraft is certificated to fly above FL400.  Aircraft certificated to fly between FL250 and FL400 can use diluter demand equipment.

[cav58d]

Im curious to whether windshield heat was on prior to take off, and if not, did they throw it on in cruise, resulting in the spidering?  If not, possibly a short in the heating, and if touched, the differential temps resulted in the webbing.  Going to be interesting to read the final report.

[Golfer]

Cav check your King Air's checklist for a cracked windshield.  I think you'll find that these guys didn't do much right and are lucky to be alive.  The very last thing you want to do is dump the cabin in this case but rather maintain a positive differential in pressure.

Also...take this and run with it to be sure to check your oxygen system prior to flight and make sure it's been turned on properly.  This has to be done on every flight (IIRC you fly a B200 or 300?)

Brush up on the procedures.  At your next recurrent this will likely be talked about (it already is being talked about in depth) to great extent and its also noteworthy because having windshields blow in King Airs is not a terribly uncommon thing.  I've seen 2 taxi back home and know personally 4 other drivers who have had them blow.

At first I thought to myself that they bunged up a roll and over G'd the airplane pulling out of the ensuing dive.  That didn't explain the broken windshield but even more to question is their actions following the routine abnormality of having a windshield panel blow.  As you know there are 2 panels and having one pop on you will pucker you up...but its no reason to panic.

Cav - did they send you to school or what other training have you gone through on the airplane?

[SFRT - Frenchy]

In the Metro with have the windshield heat on low from the time we start the engines to when we exit the runway. We had a windshield spiderweb, we saw a spark followed by the crack. I don't think that having the windshield heat on was the cause for it's failure.

[Debonair]

if ur up in teh class A, the windshied should have some sort of opaque protective cover, like maybe some old F4U or P-47 headrests

[eskimo2]

Originally posted by eagl

I also suspect that as they awoke, one of them pulled back on the controls before being alert enough to properly assess attitude and airspeed, so they may have ripped the tail off themselves.  The failure pattern (ripped off stab and wingtips bent up) don't look to me like a "simple" overspeed.
 

Good point, that makes sense.  

So how many g's do you think they pulled to wrinkle the wings like that?

[Maverick]

At least 1/2 less than it takes to pull the wings off totally.

[Debonair]

Originally posted by eskimo2
Good point, that makes sense.  

So how many g's do you think they pulled to wrinkle the wings like that?

most planes in the normal category are limited to +4 -1.5 Gs with a 50% safety factor, so maybe over 6, but if they had other stuff failing on the plane maybe it sukt so maybe less than 6, unless the failures we caused by outside factor such as collision with a micrometeoroid, then back to over 6

[eskimo2]

Originally posted by Debonair
most planes in the normal category are limited to +4 -1.5 Gs with a 50% safety factor, so maybe over 6, but if they had other stuff failing on the plane maybe it sukt so maybe less than 6, unless the failures we caused by outside factor such as collision with a micrometeoroid, then back to over 6

LOL, so enough to make them pass out again.

I bet they held their breath on the aproach and  landing just to go for a third pass-out.

[AquaShrimp]

I just want to add a few notable exceptions, not trying to contradict anything you have said.

-B-17 crews (unpressurized) sometimes flew at 30,000 feet, and a few times even higher.  

-A few tough individuals have climbed Mount Everest (30,000ft) without supplemental oxygen.

Originally posted by eagl
According to that report, they first dumped pressure and then donned O2 masks.  If I recall my training correctly, at 27,000 ft the time of useful consciousness can be as low as 30 seconds and significant impairment can occur almost immediately, so it is very possible they were already hypoxic and unable to accomplish the oxygen procedures within seconds of dumping cabin pressure.

I also suspect that as they awoke, one of them pulled back on the controls before being alert enough to properly assess attitude and airspeed, so they may have ripped the tail off themselves.  The failure pattern (ripped off stab and wingtips bent up) don't look to me like a "simple" overspeed.

None of this is particularly unusual or unexpected during or after a hypoxia event, except the fact that they survived.  The expected result from a chain of events like this is death.  Getting on oxygen immediately and if possible BEFORE dumping cabin pressure is absolutely critical, as is descending immediately.

Also of note is that pressure breathing is required above around 25,000 ft otherwise your lungs will not absorb enough oxygen.  So even if there was plenty of unpressurized oxygen flow when they donned the masks, a bad mask seal or a delay in descending to a lower altitude could have still resulted in hypoxia and unconsciousness.  This is why unpressurized military aircraft are limited to 25,000 ft and below.  Pressure breathing is not comfortable even when properly trained on a recurring basis.

[eagl]

Shrimp,

You're right.  But don't forget a few things...

Every everest climber who goes up without O2 has trained for many many years to acclimatize for that environment.  There are massive physiological changes that have to occur to be able to do that.

The experiences(and mysterious deaths) of those WWII pilots and the early jet pilots directly led to a lot of very strict rules.  Another issue with high altitude flying is the potential to get the bends.  It took years of research and collaboration between diving and flying pioneers to figure out what was going on there and to set limits.  We know now that 25,000 is the max safe altitude for unpressurized aircraft because bad things happen to even highly trained and acclimatized pilots above that alt.

I know of highly experienced T-37 pilots who nearly died following just 2 1.5 hour sorties above 23,000 ft, due to the bends.  As a student, I personally experienced moderate hypoxia at 17,000 ft following an oxygen regulator failure, and the only thing that saved me was the instructor in the seat next to me because I wasn't experienced enough to recognize the early symptoms.  I sure as hell know those symptoms now, but the first time you are in that situation it is unlikely you'll recognize the problem until it's far too late.

Our training shows us that even doing simple math (what is 5+7?) for more than 30 seconds above 23,000 ft without oxygen can be impossible.  The first time I went through altitude chamber training, I thought I was doing fine for 2 minutes but after I went back on oxygen, the instructor showed me what I'd written... Apparently at 23,000 ft without oxygen, 2+2 equals four thousand plus some other meaningless squiggles