Roost Air Lounge => Aviation related topics => Topic started by: TheSoccerMom on February 09, 2007, 07:33:31 AM
Title: King Air Survives Structural Damage
Post by: TheSoccerMom on February 09, 2007, 07:33:31 AM
Just saw this and thought it was quite the story!
"On Feb. 2, Super King Air B200 N77AJ survived an uncontrolled descent and structural damage after the inner ply of the windshield cracked at 27,000 feet and the pilots depressurized the airplane and disconnected the autopilot. According to the NTSB, the crew was unable to use the oxygen system and evidently lost consciousness. They revived below 10,000 feet, managed to recover control of the aircraft and made an emergency landing at Cape Girardeau, Mo. The horizontal stabilizer, elevators and wings were severely damaged."
The article continues to mention the windshield construction, two parts with a Mylar layer in between, and they said the crack first appeared in the lower left-hand corner. The NTSB stated that the O2 system functioned normally when tested. [from Aviation International News].
We had a windshield shatter but remain in place after we hit a duck (we think -- apologies to Turbomallard!!!) at 17,500 feet one night, also in a King Air B200. The Mylar held the saggy mess in place, and we landed without further excitement, but it was hard to see and since it was at night, the shattered pieces turned the airport lighting into millions of pretty starbursts. Though, we didn't really think they were too pretty THAT night! ::sweat::
It's great these pilots got down safely!!!!!! |:)\
Title: Re: King Air Survives Structural Damage
Post by: Baradium on February 09, 2007, 10:10:24 AM
Pictures of the aircraft are posted on our bulletin board at work. The story does not do it ANY justice without them.
The wings have creases in them and most of the horizontal stab is *gone*. The first half of it seems to be peeled off and back over the top and half of the elevator is gone.
For those not familiar with King Air systems (they are the same as on the Beech 1900 I fly), the oxygen system has a pull knob on the captain's side on the far left side of the panel for oxygen. Most of the captains I fly with leave it pulled out in flight as there is a risk of the valve being frozen at altitude (however slight). It also means you have to use precious seconds to pull the valve in an emergency. This means that if you just don the oxygen mask, there is no O2 until the knob is pulled. Sounds like either they forgot to pull the knob or the valve was frozen when they tried to. I do fly with an occasional captain who doesn't pull the knob. I imagine all the regular king airs are the same...
The passenger oxygen system for us is deployed by a second knob under the first one.
The article that accompanied the pictures I saw at work stated that the aircraft was extremely difficult to recover and once recovered they could *only* maintain IIRC 160 kts in level flight. Attempts to increase airspeed let to a climb, attempts to reduce it led to a descent.
http://www.aero-news.net/news/commbus.cfm?ContentBlockID=9e31e19e-6834-497b-96bd-3e8848d38561&Dynamic=1 This article has pictures, although it's not the article I read from work.
Title: Re: King Air Survives Structural Damage
Post by: Gulfstream Driver on February 09, 2007, 03:46:05 PM
Whew! :o
Title: Re: King Air Survives Structural Damage
Post by: Baradium on February 10, 2007, 08:40:51 AM
We dug out our checklists today out of curiousity... at least in the 1900 the checklist specifically tells you not to dump cabin pressure for a windshield cracking situation...
However, the one for side windows *does,* maybe they looked at the wrong one?
Title: Re: King Air Survives Structural Damage
Post by: BrianGMFS on February 10, 2007, 10:20:05 PM
We had one of our King Air C-90's windshields cut loose last winter on a flight (the inner glass was totally shattered on the FO's side). the crew declared an emergency, descended to below 10,000 then depressurized...landed without incident and later in the day flew the plane back home on a ferry permit. Last week we also replaced a windshield in on of the King Air's due to a a spot that looked like it was delaminating....
Brian
Title: Re: King Air Survives Structural Damage
Post by: FlyboyGil on February 10, 2007, 10:52:08 PM
We had one of our King Air C-90's windshields cut loose last winter on a flight (the inner glass was totally shattered on the FO's side). the crew declared an emergency, descended to below 10,000 then depressurized...landed without incident and later in the day flew the plane back home on a ferry permit. Last week we also replaced a windshield in on of the King Air's due to a a spot that looked like it was delaminating....
Brian
What airline is that? So not to fly? :D :D
Title: Re: King Air Survives Structural Damage
Post by: spacer on February 10, 2007, 10:55:30 PM
Just reading the article, it looks as if the windshield failure somehow caused the rest of the airplane to get all bendy and break. Is there more to the story? Most folks get 'all' their 'knowledge' from the mainstream news sources and may get the idea that these airplanes are unusually fragile.
Title: Re: King Air Survives Structural Damage
Post by: Baradium on February 11, 2007, 12:18:28 AM
Just reading the article, it looks as if the windshield failure somehow caused the rest of the airplane to get all bendy and break. Is there more to the story? Most folks get 'all' their 'knowledge' from the mainstream news sources and may get the idea that these airplanes are unusually fragile.
The windshield failure and the airplane getting "bendy" aren't really related except by the windshield causing the crew's actions.
What happened is the crew dumped the cabin pressure (normally it's pressurized so it's like you're at a lower altitude). They failed to get oxygen (reasons unknown at this time) and passed out. When they came to they were in the descent.
Now, the aircraft isn't going to react very much from just losing cabin pressure and the windshield won't really cause a problem with the flight characteristics since it didn't actually break.
It's unclear to me whether they tried to initiate an emergency descent or not after they disconnected the autopilot.
Emergency descent for a B1900 (should be very similiar or the same to this kingair):
Props forward Power Idle (the two combined is a LOT of drag to slow you down). Flaps takeoff (once below speed) Gear Down (once below speed, 180 kts). Maintian 180 kts and 30 degrees of bank.
This keeps you below any limitations on the airframe while keeping you in a very fast descent.
Obvious from the start is that they easily exceeded 180 kts. They also would have exceeded barber pole (mach related limitation that changes with altitude) and I'd bet Vne. How fast they tried to initiate a recovery at high speeds may have also affected the airframe (the last thing you want to do is just yank back on the yoke trying to level off as that can cause damage like you see). Above manuevering speed (188 kts in a 1900) full control deflection can cause aircraft damage and the aircraft will not stall before exceeding limitations.
My guess is they never got to the point of starting the emergency descent checklist, but I'm not sure. Pictures of the flaps would help indicate whether they were deployed as well as the gear doors. My theory is they somehow had a pull to the left or the right and the aircraft rolled over on its back, starting the descent as it rolled. This could be either trim related or one of the pilots giving input as he started to pass out and holding the force in as he was passing out. That's the only way that the aircraft would vary that much from its trimmed airspeed that I can think of. Once you start getting to the 90 degree point (in bank) the airspeed will be climbing dramatically and once the aircraft is on it's back the trim forces pitch it down as they attempt to decrease airspeed, increasing pitch with the increase in airspeed resulting in a very rapid airspeed gain. This is essentially a Split S manuever (think, roll inverted and do a half loop to come out on the bottom in level flight). Without props up and idle power, the amount of drag is significantly reduced. Even if the manuever is possible given an appropriate aircraft configuration, I doubt it is with cruise power set on the aircraft.
Title: Re: King Air Survives Structural Damage
Post by: spacer on February 11, 2007, 04:08:14 PM
...which illustrates my point nicely. Thanks. |:)\
Title: Re: King Air Survives Structural Damage
Post by: TheSoccerMom on February 16, 2007, 11:18:34 PM
Here is a link to a local TV station where the King Air finally got back on the ground. Some of the comments don't match what I have read so far, e.g., that the pilots depressurized the a/c (TV says the windshield blew out - it didn't), and that the pilots "came to" around 10,000 feet (TV says around 7,000 feet).
Title: Re: King Air Survives Structural Damage
Post by: TheSoccerMom on February 16, 2007, 11:20:15 PM
Sorry gang, I am doing something wrong here with the link but have been trying for some time to figure out WHAT. ::banghead::
I'll keep trying!!!! ::loony::
Title: Re: King Air Survives Structural Damage
Post by: TheSoccerMom on February 16, 2007, 11:24:33 PM
Well, it does work if you copy it into your address line... sorry I am so technologically challenged!! Now you really know why I love OLD airplanes... just my SPEED.... ahem.....
8) 8) 8)
Title: Re: King Air Survives Structural Damage
Post by: switchtech on February 17, 2007, 03:37:48 PM
Well, it does work if you copy it into your address line... sorry I am so technologically challenged!! Now you really know why I love OLD airplanes... just my SPEED.... ahem.....
8) 8) 8)
We're those photo's posted of you in another thread recent? 'cause you don't look old in them. ::wave:: Now me on the other hand (the one picture I posted of getting my Solo certificate is a long time ago - when I still had color in my hair that wasn't added in... :o
Title: Re: King Air Survives Structural Damage
Post by: TheSoccerMom on February 17, 2007, 08:56:18 PM
Oh dear, now I will have to wonder if my disguises are up to date... Hmmm... I am not sure which photos those would be? :P
But, I feel I could probably beat most folks around here in an Old Age contest... Hmmmm... "Gentlemen! Start your walkers!!" (Well, maybe I am not quite to that stage YET...) Though I do see myself still hobbling out to the airplane decades from now..... :D :D :D
Title: Re: King Air Survives Structural Damage
Post by: Gulfstream Driver on February 26, 2007, 05:19:42 PM
Back to the video, I'm surprised they allowed that guy to film the plane after they landed. Wouldn't the company want to keep a lid on that until after the investigation?
Title: Re: King Air Survives Structural Damage
Post by: Baradium on February 26, 2007, 06:49:27 PM
Back to the video, I'm surprised they allowed that guy to film the plane after they landed. Wouldn't the company want to keep a lid on that until after the investigation?
The pilots probobly just wanted to get out of there. As far as the company is concerned, they wouldn't have had anyone on the scene anyway. Nevermind that at that point it was on a public ramp so there's not much stopping the local pilots from going out and looking at it.
I'm curious what the NTSB report will say.
Title: Re: King Air Survives Structural Damage
Post by: undatc on February 27, 2007, 01:46:32 AM
or even if there will be a report. Isnt there some thing in there that says it has to be of a certain severity to even be reported? I know when one of our warriors hit a deer and basicly destroyed a wing and a landing gear strut it was never reported.
Title: Re: King Air Survives Structural Damage
Post by: Baradium on February 27, 2007, 01:57:59 AM
or even if there will be a report. Isnt there some thing in there that says it has to be of a certain severity to even be reported? I know when one of our warriors hit a deer and basicly destroyed a wing and a landing gear strut it was never reported.
I believe one factor is whether it happens in flight. That aircraft is probobly totaled I imagine... the entire airframe looks like it's been overstressed, I wouldn't be surprised if the fuselage is bent. I'd think they'd do a report on that one because it did such a large amount of damage and came so close to being a fatal one.
Remember, an aircraft that only goes up to 25,000 ft, regardless of what cabin altitude it maintains, is NOT considered pressurized at this time by the FAA. Below 25,000 you also don't need quick donning masks. This is why on our 1900s the passenger oxygen masks are "automatically" deployed by us pulling a knob. The crew masks are under covers above our heads and there is a knob to start oxygen flow to them as well (most of our captains leave it pulled as I believe I mentioned earlier). I could see an incident like this causing a change in the way of thinking for oxygen systems. If they determine that the O2 knob was frozen or similiar it could change their way of thinking regarding flow to the masks. The aircraft this happened to was very similiar to what I fly. Imagine if something like this happened on an airliner filled with passengers.
I'll be quite surprised if they don't do a report simply becuase the number of 1900 airliners there are flying around that use similiar or identical systems.
Title: Re: King Air Survives Structural Damage
Post by: tundra_flier on February 27, 2007, 05:02:00 AM
or even if there will be a report. Isnt there some thing in there that says it has to be of a certain severity to even be reported? I know when one of our warriors hit a deer and basicly destroyed a wing and a landing gear strut it was never reported.
I believe one factor is whether it happens in flight. That aircraft is probobly totaled I imagine... the entire airframe looks like it's been overstressed, I wouldn't be surprised if the fuselage is bent. I'd think they'd do a report on that one because it did such a large amount of damage and came so close to being a fatal one.
Remember, an aircraft that only goes up to 25,000 ft, regardless of what cabin altitude it maintains, is NOT considered pressurized at this time by the FAA. Below 25,000 you also don't need quick donning masks. This is why on our 1900s the passenger oxygen masks are "automatically" deployed by us pulling a knob. The crew masks are under covers above our heads and there is a knob to start oxygen flow to them as well (most of our captains leave it pulled as I believe I mentioned earlier). I could see an incident like this causing a change in the way of thinking for oxygen systems. If they determine that the O2 knob was frozen or similiar it could change their way of thinking regarding flow to the masks. The aircraft this happened to was very similiar to what I fly. Imagine if something like this happened on an airliner filled with passengers.
I'll be quite surprised if they don't do a report simply becuase the number of 1900 airliners there are flying around that use similiar or identical systems.
I think you're right. There will be some major studying of all the systems and the structure on this one. The NTSB and manufacturer will want to find out what failed, what didn't and where they can make improvements to the plane and procedures. It's a rare opportunity, since this sort of situation usually results in digging tiny pieces out of the ground. ::sick::
Phil
Title: Re: King Air Survives Structural Damage
Post by: Gulfstream Driver on February 27, 2007, 04:47:14 PM
Did they ever say if there were passengers on board?
The definition of accident has a dollar value attached to it, though I forget what that amount is. I'd bet that this damage exceeded that amount.
