Radar Data: AirAsia Plane Climbed At Speed 'Beyond Normal' And Then Stalled

Business Insider ^ | 01/20/2015

[SeekAndFind]

An AirAsia plane that crashed into the Java Sea last month with 162 people on board climbed at a faster than normal speed and then stalled, the Indonesian transport minister said Tuesday.

Flight QZ8501 went down on Dec. 28 in stormy weather, during what was supposed to be a short trip from the Indonesian city of Surabaya to Singapore.

Indonesia's meteorological agency has said bad weather may have caused the crash, and investigators are analysing the data from the jet's black boxes before releasing a preliminary report.

Just moments before the plane disappeared off the radar, the pilot had asked to climb to avoid the storm. He was not immediately granted permission because of heavy air traffic.

"In the final minutes, the plane climbed at a speed which was beyond normal," Transport Minister Ignasius Jonan told reporters, citing radar data.

"The plane suddenly went up at a speed above the normal limit that it was able to climb to. Then it stalled."

[Pecos]

When I wrote, I was thinking of the parallels between wind action in a thunderstorm, and flying in mountains in that a pilot can momentarily get confused as to the correct action to take in a temporary updraft.

[expat2]

Yes, your suggestion was/is a possibility, but it might have been a stall produced rather than just a dive. But the FCS computer might have been the problem (like the Paris airshow crash, post 12) rather than the pilot.

[webheart]

I must be getting cynical in my old age. My first thought upon reading the headline was “whitewash”. Or “hogwash”, maybe. I can’t get myself to believe that the crash was the result of weather or system malfunction. We can spend all day debating and theorizing and talking about all the possibilities, but we will never get anywhere near the truth.

[VTenigma]

“Airbus pitot tube icing?”

I said this on a thread when it first happened and got flamed. I think Air France ha similar flight data. If it ain’t Boeing I’m not going.

[Reeses]

Button pusher pilots need a panic button hooked up to a basic flying computer for when they run out of ideas.

[NY.SS-Bar9]

The copilot. The pilot was not in the cockpit till too late.

IIRC there were three crew members. The Senior captain was sleeping after an all-nighter with his GF in Rio, leaving two juniors as PF and PNF. He left the cabin shortly before they were due to hit some dicey weather. He returned in time, but did not recognize what was going on quickly enough (or at all).

[JoeFromSidney]

Button pusher pilots need a panic button hooked up to a basic flying computer for when they run out of ideas.

A crash is when you run out of altitude, airspeed and ideas, all at the same time.

[pfflier]

I made no claim the pilot was manually controlling the airplane. Regardless, if the crash was caused by faulty instrumentation, systems or pilot input, he is ultimately in charge of controlling or correctly interpreting these things. Failure to do so and losing your plane defines pilot error.

[expat2]

Not so. If the primary cause is, say, a control cable to the tailplane snapping (or a critical instrument failure in IMC), that is not listed as pilot error, but a systems problem. In the Airbus case, the ‘control cable’ is an FCS computer and an electrical wire.

[pfflier]

An updraft with a strong vertical vector likely would not affect forward airspeed indications. It is plausible that the pilot might push the controls forward and that would put the plane in a nose down attitude. This would increase airspeed and could reach a threshold of causing structural damage. The location of the the main parts of the plane wreckage would indicate that i.e. large separation of wings, tail , fuselage secions would indicate break-up.

It is conceivable that if a plane is on the edge of it's performance envelope or encountering icing conditions a significant change in altitude could induce controlability issues.

[pfflier]

Airbus = nasty. I would rather walk than ride in one of those kludges.

[pfflier]

I was ambiguous when I said systems in my last response because I was was referring to the pilot-airplane control interface systems which I didn't explicity say.

No modern fly-by-wire design has a single point failure mechanism in any aspect of flight control systems.

The FCS controllers are typically triple redundant and the control system actuators also have redundancy.

In addition reliability testing is done to the nth degree on all electro-mechanical systems that actuate flight control surfaces.

Aircraft break-up, serious design flaws, serious software errors or pilot error are realistically the only things that could compromise the systems.

Entering weather, even thunderstorms would likely not be the cause of the crash, just a contributing factor. If the pilot lost his plane solely due to the thunderstorm, then, again it is pilot error because he made a bad decision to penetrate the storm.

My bet on the outcome of this investigation? The finding will be pilot error.

[expat2]

I consider myself quite knowledgeable on the subject of redundant high-reliability FCSs.
It is true that a TMR system is pretty reliable (provided each channel has different software) if you can guarantee that you will never have more than one fault at the same time. However, in a double-fault situation, the FCS operation will breakdown (as appears may have happened in the Brazil crash). There is also a failure mode called the Byzantine Generals problem that it cannot handle. TMR is Ok for say mail/FedEx and military aircraft, but others feel it is inadequate for airliners.

[expat2]

I should add that you are probably right when you say that it will probably be called pilot error, anyway. The airline manufacturers such as Airbus bring intense pressure to bear on not blaming their product. The $$$ involved in that blame issue are enormous. IIRC the Brazil crash was blamed on pilot error, even though the pitot-head design was faulty and screwed up the air data input to the rest of the FCS.

[BatGuano]

Two things here...1 use the weather radar as an AVOIDANCE tool, not a penetration tool; 2 If the airspeed indicator does not work or is giving erroneous information. Place the throttles in a known cruise position, usually jut forward of straight up, and put the nose in a cruise attitude, usually a few degrees nose high, and you might not be in perfect shape but the airplane is in relatively stable flight, i.e. it is not losing or gaining altitude or airspeed at a more than manageable rate.
Respect T’storms, they will kill you.

[chimera]

Sounds like you are describing an aircraft in proper trim. I am nobody's pilot, but I have heard that a properly trimmed aircraft will neither gain nor lose altitude in straight flight, so the pilot can take his hands off the yoke (and no autopilot, of course) and the plane will continue on in a straight, level path.

Do aircraft still use some modern version of the old Ryan Stormscope? Paul Ryan (not the Congressman) is one of our alums:

Good Buckeye Engineer

[central_va]

You trim for airspeed, not altitude. Power controls altitude.