Posted on 05/23/2011 6:36:43 AM PDT by libh8er
What happened on board the Air France jet that crashed into the Atlantic en route from Rio to Paris? According to information obtained by SPIEGEL from the analysis of flight recorder data, pilot Marc Dubois appears not to have been in the cockpit at the time the deadly accident started to unfold.
The fate of Air France Flight 447 was sealed in just four minutes. That short time span began with the first warning message on one of the Airbus A330 aircraft's monitors and ended with the plane crashing into the Atlantic between Brazil and Africa, killing all 228 people on board.
Since last week, investigators from France's BEA civil aviation safety bureau have been analyzing the flight data and voice recordings extracted from the cockpit of the Air France flight that crashed on June 1, 2009 while traveling from Rio de Janeiro to Paris. What they have learned from the recordings seems to suggest both technical and human failure.
Sources close to the investigative team have revealed that the recordings indicate that Marc Dubois, the aircraft's 58-year-old pilot, was not in the cockpit at the time the trouble began. It is reportedly audible that Dubois rushed back into the cockpit. "He called instructions to the two co-pilots on how to save the aircraft," the source with inside knowledge of the investigation told SPIEGEL.
But their attempts to save the plane were ultimately in vain.
At the beginning of May, underwater robots were able to retrieve the flight recorders from the wreckage almost four kilometers (2.5 miles) below the surface of the Sargasso Sea. Two weekends ago, investigators succeeded in extracting data from the black boxes. Within 24 hours, reports were circulating suggesting that the crash seemed more likely the result of pilot error than a manufacturing flaw by Airbus.
(Excerpt) Read more at spiegel.de ...
“There’s a point where things are too far gone to correct, no matter how much altitude you have.”
The only point is when there isn’t enough altitude or when the plane loses a control surface. Depending on the design of the airplane there are very few stall conditions which are not recoverable given altitude and a working airplane.
There are backups on most airplanes, these generate their own risk. In my complete amateur opinion the engineering of the Airbus is not all that great in a number of areas.
It should indicate something when the last line of code reads: “Our Father, Which Art in Heaven...”
LOL let me clarify my post.
It’s not that a Cessna 180 is my best friend as a VFR pilot ...
a 180 DEGREE TURN is my best friend as a VFR pilot!
I also employ the VFR qualifier — the piece of cardboard with the square hole cut in it — hold it up to the sky — if you don’t see bright blue, keep your flying to the hangar.
ONE TIME my FIL and I got caught by a fast-dropping summer ceiling in the Tri-Pacer. We ended up scud-running for the last 30 minutes. Fortunately he had flown hundreds of hours in the area as a firespotter and knew where ALL the radio towers were. Bumpiest ride I have ever endured. Never again. Lesson learned. (he was the PIC, but still no excuse)
Failing that, the 4Cs might save my arse.
I’m familiar with pitot heat. In light planes you need to get it on prior to, or immediately upon, entering icing conditions. Not sure about airliners. Regardless, the tubes don’t expand to crack off built-up ice like deicing boots do. If the heater(s) or electric failed, they’d lose airspeed data, which is critical for manual or computer control.
It sure would be nice to be able to deploy a fresh set of tubes.
Yes 35,000 feet gives you a pretty good safety margin under normal conditions, but when your nose is pointed straight at the ground... not 4 minutes worth.
Not to be overly melodramatic... but many years ago on a dark and stormy night my wife and I were returning from Southern California to the Seattle area. It was pitch black; we were hitting nasty turbulence; the rain was pounding against the wind shield; we were flying low to try and avoid the scud that we kept finding ourselves in; we were running low on fuel; there were no good places to land; we were too far into it to turn around; we had been running behind all day and no flight plan had been filed, we hadn't even called friends or family to tell them what we were up to; my wife was crying and sobbing that she would rather be giving birth again. It was at that time that it dawned on me how people crashed their perfectly good airplanes with perfectly good instruments and even GPS. If I had made one bad move, I knew that seconds later we would be dead... John Kennedy Jr. dead.
My wife of course had suggested hundreds of miles earlier when we first found ourselves flying VFR over mountains between two layers of clouds with lightning in the distance ahead of us that we should turn back. I had insisted that the forecast and the weather reporting stations ahead indicated that all was well. That was the last time that I was allowed to override her intuition.
I have a home-built ultralight, a skypup. It is made mostly of sheets of styrofoam insulation; it shares some characteristics with a cub. The stall speed is only 25mph. If you can figure out which way the wind is blowing you can land it at running speed. People have managed to crash them, but I know of no one who has managed to kill themselves in one. I love the thing; it doesn't even have an airspeed indicator.
They flew into an area where icing was likely to occur, even if it wasn't a turbulent area.
As a private pilot myself, your story was chilling. Thanks for sharing. When I read of weather related accidents of small aircraft, I always imagine the pilot and passengers last moments. Equally chilling.
For several years now, Airbus has offered its customers a special safety program - called "BUSS" -- at a cost of €300,000 per aircraft. If the airspeed indicator fails, this software shows pilots the angle at which they must point the plane. It is a retrofit option for A320/A330/A340 aircraft, but it has been a standard fit on the A330/A380 aircraft, likewise the automatic TCAS functions are supposed to standard on the new aircraft, and a retrofit option for existing aircraft. The simple reason that it is not required equipment is that it is not a certification requirement.
ALL pilots are taught how to fly with unreliable airspeed (fly pitch/power)...in order to even use BUSS, you have to realize that you have unreliable airspeed, which means the crew should have gone to pitch/power anyway. Airbus themselves doesn't recommend the use of BUSS at the altitude that AF447 was at.
Moreover, the airframe has 3 independent air data computers, as well as the standby instruments. The information from the three angle of attack vanes is fed into the three air data computers, before being calculated into information presented on the PFD. If one has a loss of air data on one of the three independent systems, the pilots will replace the faulty air data with the spare.
To get to a situation where you have no air data available, you need to have the loss of all three air data computers, as well as the standby airspeed indicator and altimeter, and certification authorities see that is a very rare event.
Air data is nice to have, but it is not essential, pilots can still fly and aircraft based upon attitude and thrust, loss of air data alone should not cause a crash.
It boils down to: "Would pilots even use BUSS if it was available?"
Non-pilots would almost always answer "Yes"... For some (current and former) pilots, it would be a "No" (and one's a former Airbus a test pilot, but he'd probably still use it if he's line flying and the procedure calls for it).
Another thing about BUSS is, it's not something that you should rush into... You go there when you get NAV ADR Disagree, i.e., when the aircraft cannot determine if it has 1 correct vs 2 wrong, or 2 correct vs 1 wrong, due to the discrimination logic), and after you determine that you (as a human) cannot determine which one is correct and which one is wrong, or ALL is wrong... then, you take a leap of faith by disassociating flying with air data, by going to inertial data only... ie: switch all ADR to off.
Simulator refresher scenarios entail total blockage of all pitot tubes (according to Airbus this is "very unrealistic") just when reaching acceleration height after take off at night over water.
This will cause the same (false) speed indication on all indicators. Plus, as you have just lowered pitch to accelerate and retract flaps, one can miss the unusually quick rate of speed increase (because of the blockage, indicated speed will increase with altitude even if you are not accelerating the aircraft).
As all speed indications have the same error, none is rejected by the computers and the high speed protection will eventually engage, pitching significantly up to reduce speed (you cannot override this pitch up).
Switching all 3 ADR (Air Data Reference) to OFF will force reversion to direct law (thus canceling all speed protections) and you can revert to basic pitch & power flight. If installed, you will also see the BUSS (basically an AoA indication) activated.
However AF447 was at cruise flight level, not at low altitude, where the center of gravity will be very far aft as per system design (fuel distribution into elevator trim tank). Any aircraft with far aft CG at high altitude is very, very tricky to control manually!
Now here are some of my personal thoughts about possible AF447 scenarios:
They seem to have tried to cancel the speed protection as indicated by the PRIM and SEC FCC going off line (ACARS messages received show they were switched off and did not trip off).
They could have successfully done this by switching all 3 ADR to OFF, but they would then have had to fly the aircraft with far aft CG in direct law at high altitude and in strong turbulence...
Speculations however will not solve this accident, but as anyone can see this is not a simple right or wrong, good or bad pilot/airplane thing at all. I am certain the fellows in the front office tried till the very last second to safe all souls aboard and their ship.
Thank you for your detailed explanations! You obviously have a high degree of technical knowledge and are able to present things in a way that makes it much easier for the rest of us to understand. Thanks for taking the time to do this.
If they are just now downloading the data recorders, where did the information for this graphic come from? Or is this just speculation?
'Furious' relatives accuse Air France, Airbus of cover-up
AF447 - Unreliable Speed - by Joelle Barthe, Airbus Engineer
Oops. Oh well, the Tri Pacer is a nice plane too! LOL
The plane was sending back data continuously even during the failures that caused it to crash. I assume that’s where the graphic came from.
My next door neighbor is actually an engineer who works for the FAA. I am not sure what role he plays in accident investigations, but he does get sent on long trips fairly frequently after high profile events to help decide what the FAA should be doing to prevent further tragedies. I am sure that he has an opinion on this.
I really like Tri Pacers also. We came very close to buying one on a couple different occasions. I was out flying my ultralight one day and the old guy in the hangar next to ours gave my wife a ride in his Tripacer. When I got back to the airport... my wife told me that we needed an airplane that she could go flying in too. I like to tell other pilots that I am the first husband in the history of aviation whose wife said, “We need to buy an airplane”.
Get the jets AoA in excess of 70o and pull the throttles to idle. The low speed warning horn will be imminent. Once it sounds, yank the stick for all you're worth and roll the aircraft to design limits.
Ergo: the airframe will flutter like a leaf, but fly like a brick.
The pilot then calmly hits the 'manual pitch over-ride' to disengage the computer limited flight controls and then sycle the stick in phase with the pitching moment of the aircraft, i.e., apply forward pressure on the stick when the nose dives (or pull when inverted), and release pressure when the nose rises; simultaneously with this application of rudder. Eventually the contol surfaces will bite and the nose will remain pitched down. Remain pitch down until IAS exceeds 200Kts (if inverted to not roll the AC upright until that speed has been exceeded). 5000' AGL is pushing recovery to the limit on an unloaded bird.
Let's simplify the situation greatly:
- IMC
- Engines out
Questions:
Is power available for flight instrumentation/computers?
Hydraulics & electric for controls?
Do they fly with the APU running, or can they fire it up quickly and in those conditions? Are there battery backups to keep the flight computer online?
Even if their pitot static systems are clear and they have attitude information, what can they do without adequate flight controls or power (thrust), especially in turbulence?
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