Air France jet vanishes

I have spoken with some of my old buddies at the Kite Factory and the opinions that I got fingered the faulty airspeed indications that allowed the crew to fly into a violent thunderhead too fast and the airplane broke up....with the possibility of the vertical tail coming off first.
Switches

 

Absolutely fascinating thread, thanks to all who contribute such knowledge.

Bit of a tangent, apologies but this is really bugging me - The reference to AA587 crash led me to scan the NTSB report (not read in full, apologies if I've missed something but the summary villifies the FO so they better not cite mitigating factors in the body of the document) - is it really the case that an aircraft was damaged by the control inputs of the First Officer?

Literally one of the guys flying the plane broke it? If the vertical stabilizer is not designed to withstand certain inputs while at certain speed/attitude then why would the aircraft "permit" those inputs? Shouldn't they be limited by hardware or software controls?

 

It's possible to break just about any airplane in flight using sufficient control inputs.

 

I think those poor pitot tubes are going to take the brunt of the blame here. After all, it's much better for Airbus, Air France, the Government of France, and many other stakeholders if a simple, clear problem is identified and fixed-- even if it wasn't really the cause of the accident.

After all, if it turns out that the entire flight control and design philosophy of Airbus is the issue, that's very troubling. Far more comforting to replace some defective pitot tubes.

 

As I mentioned in post #64,
"It was not only one hard directed command but a series of two HARD alternating inputs to the rudder in opposite directions that the NTSB felt added to the incident of the fractured the fin on that A300. (This was taken from the black box)"

It was also noted in the report that the FO had used this type of input in other aircraft previous to this incident.
This was NOT considered an accepted method of control during turbulence.

 

Arrogance kills, and I'm not directing that comment just to Airbus.
I run into it when certain engineering designs are questioned in general.

 

The day after the AA crash in New York I was talking to my neighbor, at the time an accident investigator for AB, when he said, "Oh, you can fly the tails right off of those planes if you're not careful." If it's a weakness in the design, AB knew about it long before that episode. I'm not an airplane guy, as many here are, but it made me wonder.
Regards,
Tom B

 

Hard being 32lbs of force and 1.2 inches of travel. Gosh, not much margin of error.

 

If that is all it takes for full deflection in either direction? Yes.

More accurately, change the word "hard" for "sudden". This is the context I was using.

 

Right, they definitely speculated sudden and alternating inputs. Guess I'm just surprised that there aren't hardware or software locks in place which stop the input in the first place, perhaps I'm being naive, not truly understanding how complex an aircraft is. Makes you appreciate the skill of the crew more, and worry about untrained crew also.

 

There is software on the Airbus to limit deflection but it is for high altitude, high speed cruising since the forces are so much higher. It is listed as one of the first things that showed a fault in the ACARS log (link) posted earlier in this thread. "Rud Trv Lim Fault"

 

One of the flight test protocols for certification is to fly the aircraft 10% past it's maximum speed and then fully and suddenly deflect each of the controls in turn. So a simple full deflection in one direction won't break an aircraft. Airbus has it's rudder travel limit to comply with this requirement, I'm sure (so do other aircraft- the Falcon series, for instance).

 

I can't remember the exact airspeed when the limiter comes into play on the A300 but as I recall from the NTSB report, the airplane was just under where the limiter should have worked. The FO had a habit of getting crazy legs when in turbulance. Some had indicated that he was a bit of a nervous pilot and they do exist. As stated before he went full defections four times. My understanding is that had the airplane been about ten knots faster the limiter would have prevented such heavy forces from being applied.

Again on the pitot tubes, there was ADR (air data reference) computer disagree ECAM message and ACARSed to Airbus headquaters. This implys that one tube was bad or one of the ADR computers went bad. At any time the Airbus is in what is called Managed Speed the computer constantly adjusts the airspeed for a certain pre-programed protocol. For our airline it was more effecient and less on speed but it can be adjusted under an input called Cost Factor for each flight. The computers then monitor the air density, temp, winds, everything really and adjust the speed on its own for highest efficiency. That is why if the ADRs were all interpreting bad info, the theory would follow that the airplane just flew into the turbulance beyond its max turb. air penetration speed. What doesn't follow is that the auto thrust went off 4 minutes before the final failures of the electrical and cabin pressure. So managed speed would no longer be active and the airplane would not be maintaining the speed.

You have to look at the master warning messages that also went off. The first problem was in the flight control computer not the ADR. Two different systems. Not to say that a pilot could not have gotten happy feet after the flight control computer malfunctioned and the limiter failed to give proper protections, and wrenched the tail off as with the AA plane. But that does not have much to do with the ADR or pitot tubes.

As I look at the malfunctions, it started with a computer or electrial malfunction that first effected the F/CTL computer then cascaded to other systems. A bad pitot tube would not cause the F/CTL computer to malfunction or the auto pilot and auto thrust to go off line.

Additionally, all three pitot tube are heated by seperate systems I believe. I'm having a hard time believing all tubes froze over. And I'm pretty sure losing one ADR computer or having a bad pitot tube would not send the plane into Alternate Law. However, losing a F/CTL computer such as a SEC or ELAC would do that. I believe they went to ALT LAW four minutes before complete electrical and cabin pressure failure (break up).

IMO the pitot tubes will be the cover for a tragic set of events that could happen again. I hope I am wrong because I might go back to flying an Airbus at some point and have a lot of good friends are flying them today.

 

FOUR times. No wonder..........................................

As far as I'm concerned the structure should be able to withstand what ever inputs are given at climb-out speeds. (Just my opinion)

 

Could not agree more. Bad feeling thinking you have to fly with kid gloves on. Climbout you are well below Vma

As I recall the FO on the AA went full right full left full right and back full left... so four full deflections from neutral.

Latest reports saying Airbus investigation showing that the pitot tubes look like the cause... but Air France CEO not convinced... It's probably going to get ugly.

 

Spasso, Crusing- Are we seeing symptoms of an out of control situation rather than a series of indications causing an accident? It still looks to me like the aircraft departed and then sent out a bunch of messages related to the departure, not the other way around. Makes no sense otherwise. Hence all the finger pointing. Aircraft out of control due to crew actions or a combination of 99th percentile weather and crew actions, or, alternatively, aircraft malfunction that got them into an unrecoverable situation. A lot at stake here for both parties.

Taz
Terry Phillips

 

A very good way to look at it Terry.
At this stage I can't lean either way. I need more facts. Further speculation is becoming an exercise in futility.
I am kind of pulling back from this to see what develops.

 

Spasso- Hopefully with an attack class nuclear submarine now searching for the FDRs, their powerful passive sonar will find the boxes and give us some definitive answers.

Taz
Terry Phillips

 

That's what I'm hoping. If they cover enough area in time they should be able to nail it. They have VERY good ears.

 

I feel the same way. I've probably said too much already and I'm just going to wait and watch.
Switches

 

I should probably do the same since I don't know all the facts. But it's hard to not come up with some theories based upon what has been released. It may not be helpful but it is interesting.

There is no way to be certain but I sense there is a little of both. I don't think they flew into a TS and the computers started shutting down just because they were in turbulance. There would have been a much quicker series of messages if the plane started breaking up right away... not worsening messages continuing for four minutes. Additonally, Flight control computers would not start shutting down because all of the pitot probes are bad. The ADRs would but not the controls for elevators and spoilers, they're different systems. The timing of the Master Warnings and the the length of time before total failure is very important and it took some time for the complete failure.

I feel the crew dealt with a horrible series of events. One highly spectulative angle is the plane went into mechanical back up due to failures initiated by electrial and or flight control failures. With no protections the pilots are left with only the rudder to control roll and yaw. In severe turbulance without rudder travel limitations, they could easily applied full deflection in a attempt to maintain control. Based on the AA accident full application of rudder could have torn the tail from the airplane. Severe turbulance is very rare. Most casual flyers think a bumpy ride is severe turbulance, it is not. In severe, the airplane is out of control mometarily with 1000 foot altitude changes. I was only in severe once and it was not fun when I had full controls.

So to answer the question, it seems like there were a series of events that led to an out of control situation and ended with the structural failure of the aircraft.

In training on the A320 during systems we discussed a cascade of failures happening to the electrical systems and the resulting problems, the instructors blew it off as "if this happens you are having a very bad day" as if it is so unlikely don't worry about it, but if it does you're screwed. I would say though that on the airbus the most scary issue was the loss of hyd. systems. (no indication that happened on Air France) There are only three systems on the 320 and you lose those and your just along for the ride. Computers are the brains and the hydraulics are the muscles.

 

I dislike jumping to conclusions and do not think that is being done here so don't misunderstand my question but I do wonder, has it been made public how experienced the crew was? Or time in type?

 

Brian- Aircraft commander (pilot to civilians?) 11,000 hours, 1600 hours in the A330.

Taz
Terry Phillips

 

Not a rookie.