AF 447 Air France flight lost over the Atlantic

I just learned that NOVA will have a special tonight on the AF 447 flight. There are so many interesting aspects to this puzzle. Primary amongst them is the Airbus concept of a computer flying the aircraft and over-riding pilot input in certain modes. Also involved are sensor design issues, conflicting data resolution issues, pilot attention issues, international cooperation issues, search operations issues and use of maintenance data as an alternative to the unrecovered Black Boxes.

I'm uncertain if the plane deviated for severe weather or not. I think the primary problem was overspeed resulting in a deep stall at high altitude resulting in a near vertical descent with little forward speed. It would be a problem of how to evaluate fluctuating data from multiple sensors.

The flight into a severe thunderstorm may well have taken place although the pilots may have believed they were above the storm. In most stalls the rule is simple: lower the nose immediately and add power immediately. This simple rule usually results in greater air flow over the wings to generate lift. Wings are usually designed to stall from the inboard area first so that the pilot has time to react before the stall reaches the outboard areas of the wing and the control surfaces become stalled. In a deep stall, moving the control surfaces has no effect because there is no airflow over the control surfaces. Adding power may be a problem if there was a sudden and unexpected ingestion of super-cooled rainwater into the engines. If it was not just pitot tube icing but an engine flame-out, no power may have been available to the pilots even if in their information overload state of mind they realized they desperately needed to add power.

Analysis of the flight from the ACARS maintenance data transmissions is not ideal. The information is designed to give maintenance crews an indication of what systems will need to be tested when the plane lands and what tools and parts should be on hand for the task. Such maintenance data is not an alternative to a Flight Data Recorder. There are also problems since the ACARS messages are held in a one minute suspense window and are grouped by item and priority. Certain message evaluation rules are clearly compromises. A fault detected by a system is considered more serious if it relates to a separate system than if it is a self-detected internal fault. A fault is deemed to be hard if it persists for thirty seconds whereas a fault is deemed soft if it is detected for less than thirty seconds. Such rules do make sense in most circumstances.

The loss of satellite uplink carrier signal during a critical time is one argument against replacing physical black boxes with constant electronic transmission of the FDR and CVR data. The cost of such transmissions is a major problem also.

I'm sure it will be an interesting program and I look forward to viewing it. I hope all my many readers (LOL) will enjoy it.

By the way, the most relevant incident to compare AF447 with is the Gimli Glider incident. That plane ran out of fuel half way through its flight and all the design errors, pilot errors and ATC errors were countered by one thing alone, pilot expertise. The pilot had a hobby of flying gliders, so when he suddenly found himself flying a huge ungainly glider full of passengers, he still knew what to do and how to do it. He had flown gliders before. He knew to make his S turns toward his objective and not lose sight of it. He knew how to do skids. He was flying the airplane rather than monitoring computers but everything turned out okay because he was used to actually flying the airplane rather than monitoring computers. That is a rare skill nowadays.

With AF447 when things turned so bad that the computer entered Alternate Law mode the computer would no longer override disapproved pilot inputs and would allow the pilots to fly the aircraft as they saw fit. Unfortunately, the pilots were not very experienced at actually flying the aircraft and were not able to do it in situations of high informational overload, high insecurity as to the reliability of their instruments and unusual attitudes. When Fly-By-Wire ended and Alternate Law started, the situation was already critical and the pilots desperately needed a learning curve. Unfortunately, there is no learning curve during such an event. If you've entered even the fringes of a supercell at night and are experiencing electrical overloads, have circuit breakers popping all over the place, are losing some instruments and have utterly lost faith in all your instruments, the situation is hopeless for a pilot who really doesn't know how to fly an airplane without a computer.

Every flight using a computer to change altitude saves on fuel costs over a heavy handed pilot trying to manipulate the throttles, but every such flight deprives the pilot of real flying experience. Just as the Gimli Glider incident involved a sudden transition the AF447 undoubtedly involved a sudden transition even though we don't know the cause. Initial lightning seems insufficient. Iced-up pitot sensors can have any number of causes. Auto Pilot and Auto Thrust are different systems and some confusion may have existed as to speed selection and the rapidity of speed adjustment attempts that were required.

If there was a deep stall, I just wonder what attitude is required for it. Note: A Deep Stall is one wherein no manipulation of power or control surfaces will have sufficient effect. A pilot in the deep stalled plane is as utterly helpless as a pilot on the ground who might be observing the incident. The pilot on the ground will push a non existent throttle lever, the pilot in the plane will push an actual throttle lever however the effect will be the same. A pilot on the ground will push an imaginary steering yoke, a pilot in the plane will push a real steering yoke yet the results will be the same. No effect whatsoever. A deep stall with or without a flat spin would mean a high speed vertical descent with little forward momentum.

NOTE: On Feb 28 2011, the Alucia arrived, fresh from a Seattle overhaul, at the Pacific waiting area for transiting the Panama Canal to begin its three phase search for the Black Boxes using remote controlled submersibles.

NOTE: This Phase 4 search continues. IF there is a Phase 5, Recovery Phase, a different ship and different equipment will be used. So far, no debris field has been discovered much less the "black boxes". (April 2nd, 2011).

Debris Field found. Learmount of Flight International being quoted on theory of crew fatigue induced fixation on minor problem while plane was in an unnoticed gentle descent resulting in a collision of an intact and controllable plane with the sea. He does not believe there was any deep stall. Merely pilots having lost so many instruments that they did not believe what few instruments remained.