Air France crash? 2

[Higgler]

Now that pitot tube icing has been confirmed, were the pilots pulling up to slow their speed?

Why don't pilots carry an aircraft capable GPS with them in the cockpit to see their ground speed? I say aircraft capable because one pilot I knew bought a $120 GPS that had a software load which would not display speeds above 100 mph, just to make you buy the much more expensive $400 aircraft GPS.

 

[IRstuff]

They supposedly were completely flummoxed by the stall warning and were apparently doing the exact opposite of what they where supposedly trained to do.

And, they already should have a GPS system, since we can access similar data from our seats in the passenger compartment on certain airplanes.

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[rb1957]

what can we say ... it's a very conservative business.

a different question is why did they pull up when the plane was stalled (or at least the cockpit instruments said it was) ? with a frozen pitot tube mis-reporting the airspeed, i'd've thought you'd've the wings riped off from an overspeed ... plane is flying straight and level at M.8, instruments indicate a stall, stick forward, airspeed (in reality) exceeds Vd ...

and you see all the little unforeseen real world events ... the cockpit warnings cease at sometime 'cause the airspeed is less than some software minimum limit ... that probably confused them too ... "great, we've fixed that stall warning (somehow)", "oh great, no we didn't ..."

 

[Higgler]

I hope the software is changed to help pilots in similar future events.

It must be horrible for the families to find out recently that pushing down on the stick likely would have saved everyone.

 

[MintJulep]

Given that wind speeds aloft can be in the hundreds of knots knowing GPS based ground speed is at least useless, and at most hazardous.

The pilots were already confused by conflicting information.

 

[CastMetal]

Another possibility.

American Airlines flight 587

http://www.ntsb.gov/Pressrel/2004/041026.htm

Airbus aircraft have had rudder/vertical stabilizer issues in the past. Is the airspeed from the pitot tubes the only input to the rudder travel limiting system? This would make any rudder input during an iceup at highspeed extremely dangerous.

Comprehension is not understanding. Understanding is not wisdom. And it is wisdom that gives us the ability to apply what we know, to our real world situations

 

[rb1957]

i doubt that "just" pushing the stick forward would have saved these guys ... if the pitot is iced up, then the flight cntl computers are less than useless, it'll be telling the pilots crap, they won't know, and they are trained to believe the instruments ('cause in most cases they are right and the pilot is wrong ... vertigo, "loss of spatial awareness", ...).

if they had pushed the stick it would have been a race, between thawing the pitot tubes (and reacting quickly to the new condition of the airplane) and ripping the wings off.

we are unfortunately a business of ambulance chasers ... rule changes are predicted by the number of smoking holes in the ground ... no disrespect at all to any involved. I understand that Air France declined to change the pitot tubes, presumably 'cause they had no -ve experience (before now) to drive the change.

 

[Higgler]

My point of stating above info regarding pushing the stick down was based on news reports saying pilot error occurred (stick down, not up).
I realize that living in a hellish situation is extremely complicated, especially when your life is ending.

Tough job being a pilot, apologies to pilots reading this thread if my statements seem callous.

Based on news reports, I would bet the families will think pilot error caused the crash. I'd bet my life earnings that lawyers will think that.

 

[rb1957]

i didn't mean to imply i thought your comment was callous.

yeah, it'll be a field day for the lawyers. practically speaking, once the pitot system "crashed" they had just about no chance. just maybe they could retain situation awareness (at night over the ocean, in a storm ...) but the plane's computers would be telling them garbage and quite possibly limiting what they could do.

then the lawyers will leap onto why didn't Air France improve the pitot tube (with the Airbus SB, i believe) ? it wasn't serious enough for EASA to make it an AD (mandatory change). great think the lawyers ... bigger pockets to leech off.

i think it was bad luck in a very unforgiving environment.

 

[kontiki99]

I wouldn't get to invested in the news. The French agency investigating the incident will probably post a final report of some type.

I've been to their website before and downloaded all the same reports they had for the Nova reenactment of the investigation.

The media is really bad at this sort of thing.
The Nova show was awful too.

 

[YoungTurk]

I reccomend a read of the following link for a factual, but leading, account of the last few minutes of AF447. Chilling.

http://www.flightglobal.com/blogs/flight-international/2011/05/af447-after-two-long-years-six.html

The crucial bits from the above link:
-
2:10:05
"
The autopilot then auto-thrust disengaged and the PF said "I have the controls".

Investigators have not confirmed why the autopilot and autothrust disengaged, although this is a normal response of the A330 if its computers detect inconsistency in the airspeed data received from the pitot tubes on the nose.

The airplane began to roll to the right and the PF made a left nose-up input. The stall warning sounded twice in a row.
While the pilot appears to have rolled the aircraft to the left, to counter a roll to the right, he also pulled the aircraft's nose upwards - for reasons yet to be explained."

...

2:10:51
"The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight. Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt; it was then consistent with the other recorded speed. The PF continued to make nose-up inputs. The airplane's altitude reached its maximum of about 38,000 ft, its pitch attitude and angle of attack being 16 degrees.

The aircraft automatically trims itself to correspond with the nose-up attitude. In the meantime the standby airspeed indicator's reading suddenly rises, bringing it into line with the reading on the captain's display; the two speeds have been inconsistent for less than a minute.
Despite the stall condition the flying pilot still holds the nose of the aircraft upwards."
-

Don't see any way to read it other than they flew the plane into a stall. Iced pitots likely started the chain of events, but didn't cause the stall.

I recall reading something at the time about AF being unique in that the co-pilot keeps his seat when the captain goes on rest and the relief pilot takes the captain seat (instead of the co-pilot sliding into the captains seat). I can't seem to find the link now, but the story begs the question of who was at the control and how experienced they were.

 

[WKTaylor]

The #1 rule in flying is: fly the aircraft.

It appears that the crew forgot rule #1 and focused on troubleshooting the failed systems. This situation was made worse by the darkness and weather that obscured the horizon and ocean. It appears AF447 simply pancaked onto the ocean at an extremely high rate of descent, wings level, nose high, slow forward airspeed.

An EAL L-1011 crashed in the everglades for fundamentally the same reason: crew was distracted while troubleshooting a balky nose landing gear, late at night over an area area of FL with little or no visual reference [IE: few lights and non-reflective surface]. The entire crew focused on "the problem"... and simply allowed the jet to drift into the ground.

http://en.wikipedia.org/wiki/Eastern_Air_Lines_Flight_401

There are similar horror stories... such as:

The Air New Zealand crash on Mt Erebus (

http://en.wikipedia.org/wiki/Air_New_Zealand_Flight_901

)

or (possibly) the crash that killed Sen stevens in AK last year (

http://en.wikipedia.org/wiki/2010_Alaska_Turbo_Otter_crash

). FAA report indicates the single probably pilot lost situational awareness in deteriorating weather over "familiar terrain"... and delayed climbing above the scud...and flew into slowly rising terrain [CFT]. I suspect the pilot was expecting to "break-thru near his destination at any moment".

Regards, Wil Taylor

Trust - But Verify!

We believe to be true what we prefer to be true.

For those who believe, no proof is required; for those who cannot believe, no proof is possible.

 

[IRstuff]

Supposedly, the AF captain took control of the plane at the end, but it was too late to do anything by then.


TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[thruthefence]

here's another:

http://www.youtube.com/watch?v=33NUAy3eomg

 

[KENAT]

I'll have to second the questions about what the GPS buys you.

Does the A330 have a pitch indicator? If so between that and rate of descent information you might have hoped they could've done a better job, but still no guarantees by the sounds of it.

Even with artificial horizons etc, disorientation of pilots is still a leading cause of accidents as best I recall it from uni & flying training.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[Surestick]

The private pilot in me wonders if "Attitude + Power = Performance" wouldn't have saved them but I have no idea if you can hand fly a plane precisely enough at that altitude, using only the artificial horizon and the throttles, to keep it between a stall and going too fast.
I suppose you'd have the altimeter and angle of attack indications that you could still trust.
I figure idle-thrust and a conservative amount of nose down at a reasonable AoA to descend to a safer altitude would have been the solution.
Of course the big problem is figuring out which instruments are lying to you and which you can trust quickly enough to be able to do something with the information.

 

[MintJulep]

Altimeter relies on the static pressure ports of the pitot, so it may not have been working.

An attitude indicator doesn't "need" any pitot inputs. Not sure if Airbus tries anything clever.

Wings level, nose on the horizon and cruse thrust shouldn't get you in too much trouble.

 

[KENAT]

Mint, altitude/rate of decent is one place where GPS might give you some useful info even if the static port was also iced.

I was thinking of trying to adopt the optimum glide profile until the pitots cleared but it's probably a lot easier said than done.

From memory the envelope at the speeds & altitudes they fly are on the narrow side.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[thruthefence]

" Not sure if Airbus tries anything clever."

IMHO the whole aircraft is "clever".

Maybe TOO "clever" ?

I bet there was a cascade of annunciators and shed systems that these poor guys were just overloaded.

 

[WKTaylor]

Perhaps an even more similar mishap: Aeroperu Flight 603.

B757 took-off at night [in WX, low/poor visibility] and encountered erratic pressure instrument readings. The crew was unable to control the airspeed and altitude readings were totally unreliable... and the aircraft ended-up in the ocean.

When the wreckage and FDR/CVR were discovered [Wikipedia]... "investigation into the accident revealed that masking tape was accidentally left over some or all of the static ports (on the bottom side of the fuselage) after cleaning the aircraft that eventually led to the crash."

http://en.wikipedia.org/wiki/Aeroperú_Flight_603

Disorientation and/or distraction [such as messing with the radio or NAV system or texting while driving], can be fatal rapidly.



Regards, Wil Taylor

Trust - But Verify!

We believe to be true what we prefer to be true.

For those who believe, no proof is required; for those who cannot believe, no proof is possible.