Kazakhstan plane crash: Bek Air flight with 100 onboard goes down at Almaty airport

[Evan]

The Final Report is out on this one. You'll be happy to know that is only in Kazakh. I realize that some people on this forum don't speak much Kazakh, so reposting the AV Herald translation:

The investigation concludes the probable causes of the crash (the report calls it a "catastrophe") were:

The accident occurred as result of asymmetrical loss of wing load-bearing properties during the takeoff phase which caused the aircraft to stall immediately after taking off from the runway.

The aircraft collapsed immediately after leaving the runway and rolled to the right on snow covered ground, breached the airport perimeter fence and collided with a private two story building about 10 meters from the fence.

As result of the collision, due to overloading andimpact destruction and compression occurred resulting in 11 passengers and one member of the crew being killed and 47 passengers being injured in various ways.

The cause of the loss of load-bearing properties of the wings was most likely the effect of icing on the ground.

Contributing factors were:

The crew, after analysing the meteorological situation of Almaty Airport, may not have made sufficient conclusions for a more effective inspection of the entire aircraft and especially (tactile method) an examination of the leading edges of the wings.

The operators Safety Management System (SMS) only contains general provisions, specific measures were not adapted for implementation. This did not allow for timely identification and elimination of existing risks affecting the safety of flight.

Collision of the aircraft with a two story building which affected the severity of the consequences.

Conclusion: Z9-2100 may not have successfully climbed out of the runway, may have stalled and pranged back down on the runway, may not have remained on the runway, may not have avoided striking a building and 12 people may not have survived as a result. But let's wait for the... oh wait a minute...

[elaw]

It's even worse than that. Often parts (more specifically part numbers) are operator-specific, so, just as an example, a GCU from an ex-American bird might not be legally OK to be fitted to another operator's airplane until it's been ascertained that the parts are, in fact, the same, which, as is the case with many things aviation, is not always as simple as it sounds. It's all about the paperwork.

Or... they remove the ID plates from the parts, call them "good" and chuck 'em on the airplane...

[ATLcrew]

And since the Fokker 100 has been out of production for almost 23 years, most spares are probably coming from salvage and rebuilders.

It's even worse than that. Often parts (more specifically part numbers) are operator-specific, so, just as an example, a GCU from an ex-American bird might not be legally OK to be fitted to another operator's airplane until it's been ascertained that the parts are, in fact, the same, which, as is the case with many things aviation, is not always as simple as it sounds. It's all about the paperwork.

[Evan]

Hmm.... "As of July 2017, 113 aircraft were still in operational use with airlines.: (c) Wikipedia.

Also (c) Wikipedia, for is smaller sibling, the F70 "As of January 2020, 31 aircraft remain in service with 7 airlines and 2 governments" (out of 47 originally built).

And both are derivatives of the F-28 of which 241 were built (with some still in service) and which whome the F100 and F70m must share a good bunch of spares.

And since the Fokker 100 has been out of production for almost 23 years, most spares are probably coming from salvage and rebuilders.

[Gabriel]

Of the 283 built. 113 are reportedly still in service, thus about 40% of them are still in service.

Hmm.... "As of July 2017, 113 aircraft were still in operational use with airlines.: (c) Wikipedia.

Also (c) Wikipedia, for is smaller sibling, the F70 "As of January 2020, 31 aircraft remain in service with 7 airlines and 2 governments" (out of 47 originally built).

And both are derivatives of the F-28 of which 241 were built (with some still in service) and which whome the F100 and F70m must share a good bunch of spares.

[Evan]

And why can't a pepsi can be airworthy? (not-genuine question).

Amazing, there a couple hundred still flying just a couple of years ago. With so many third-world airlines in need of cheap airplanes, I thought that they would go to crash out there rather than being intentionally scrapped.

Of the 283 built. 113 are reportedly still in service, thus about 40% of them are still in service. That might explain why the spares that can be salvaged from the other 60% are more valuable than the prices those otherwise refurbished airframes would command in the third-world airliner market. The downturns of 2002 and 2008 took a big hit on them. American retired all 74 of theirs in 2002, citing operating costs. They have found new homes with small airlines that place efficiency below acquisition costs. The F-100 was designed to operate into the 2030's, but, like the 737, they are incompatible with the newest engine technology needed to compete for major airlines.

[Gabriel]

Most of them are pepsi cans by now.

And why can't a pepsi can be airworthy? (not-genuine question).

Amazing, there a couple hundred still flying just a couple of years ago. With so many third-world airlines in need of cheap airplanes, I thought that they would go to crash out there rather than being intentionally scrapped.

[ATLcrew]

Why would it be that difficult to find an airworthy F100? (genuine question)

Most of them are pepsi cans by now.

[Gabriel]

Never mind all that, I'm more curious about where they found an airworthy F100. For that matter,

Why would it be that difficult to find an airworthy F100? (genuine question)
And who said it was airworthy? From the results of the preliminary report it seems that neither the airplane, nor the pilot, nor the airline, nor Kazakhstan's CAA were airworthy.

[Evan]

Remember, all the words matter. Cessnas and F-100s should have a walk around.

Ironingly, 172s vary in fuel drain procedures...some have 3, some have 7. Water condensation tends to show itself at a particularly bad time...around and after V-2...the walk around and low point checks and visual level inspections are important.

Could the manual be important TO the walk around- maybe. As to whether you SHOULD do
a walk around...

Not as black and white as you think. In the 1993 crash, the wings were inspected by the ground crew but they couldn't reach the top surface of the outer wing. A walkaround was delegated to the Flight Station Engineer who was very experienced. He reported that the parts of the wings he could access looked melted. Had he done the walkaround on stilts, he might have saved the day. Maybe that should be SOP...

US Air flight 405, a Fokker 28, had been properly deiced but too much time elapsed between the deicing anf the takeoff. The flight crew did not perform a walkaround of their airplane, and USAir procedures did not require them to do so. It wouldn't have saved them though.

I agree that the walkaround should never be skipped.

In both of these cases however, an abundance of caution, deicing because a threat existed regardless of what the wings looked like, would have been far more fruitful than a walkaround.

But that kind of worrying is just not cowboy.

[3WE]

Yeah... cuz it's just like a big Cessna... except... does the Cessna have inner collector tanks and larger outer wing tanks?

Remember, all the words matter. Cessnas and F-100s should have a walk around.

Ironingly, 172s vary in fuel drain procedures...some have 3, some have 7. Water condensation tends to show itself at a particularly bad time...around and after V-2...the walk around and low point checks and visual level inspections are important.

Could the manual be important TO the walk around- maybe. As to whether you SHOULD do a walk around...

[Evan]

There's also this, if the F100 shares this same vulnerability with the F28:

Investigators found that a flaw in the design of the F28's wings made them extremely vulnerable to ice buildup. Because of the angle of the wings, even a very small amount of ice could have devastating effects. When the NTSB, in collaboration with Fokker, investigated the effect ice can have on an aircraft, they found that ice particles as small as 1-2mm of a density of one particle per square centimeter can cause a loss of lift of over 20%. A document written by Fokker before the accident detailed the effect of ice on the wing of an F28 warned that an "uncontrollable roll" would begin even with a small amount of ice on the wings.

[Evan]

"In the Fokker 28-100 aircraft operations manual, it clearly states that the aircraft wing MUST be checked prior to each flight"

"Because the manual says so.....?????!!!!!?????!!!!!

How many eye-roll emoji's will I need.

Evan mentality.

Yeah... cuz it's just like a big Cessna... except... does the Cessna have inner collector tanks and larger outer wing tanks? If, for example, the fuel remaining in the larger outer tanks were to be much colder than the renewed fuel flowing into the inner collector tanks, that might create warmer upper skin temps on the inner wing and if the crew member doing the walkaround was only tall enough to inspect the top surface of the inner parts of the wing, where warmer fuel resulted in melting, he might come to the conclusion that deicing wasn't needed, and yet the colder outer wings would still be iced. Just like on a Cessna... or, no I guess not.

Maybe it wouldn't be a bad idea for the manual to point out this risk, as it did, after it happened in 1993. So it doesn't happen again. Evan mentality.

Of course if you don't read stupid manual because you are great brave airman of Kazakhstan, or super pilot of the millennium from Sweet Monkey River, you might just make the same mistake.

Never mind all that, I'm more curious about where they found an airworthy F100. For that matter, WHY they chose the F100 is probably an even better question.

Iran, I expect. Although I think Skywest is still using them. I've heard that they're rather well-built, with EFIS and everything, but not well-suited to the post-recession penny-pinching shananigins.

[ATLcrew]

This comment brings sadness. For a while we[no italics] had AA F-100's competing with TWA MD-80s flying moderately full aeroplanies between Flyover and Sweet Monkey River International Airports several times a day. Hell, they'd even cancel sometimes and just shift you over to the other airline...

The MD-80s PRE and POST date the F100s.

That's about the last time I saw one, when AA still has them coming into MSP. In fact, I witnessed one do a go-around from an approach to RWY 22.

[3WE]

Never mind all that, I'm more curious about where they found an airworthy F100. For that matter, WHY they chose the F100 is probably an even better question.

This comment brings sadness. For a while we[no italics] had AA F-100's competing with TWA MD-80s flying moderately full aeroplanies between Flyover and Sweet Monkey River International Airports several times a day. Hell, they'd even cancel sometimes and just shift you over to the other airline...

The MD-80s PRE and POST date the F100s.