Dec. 28, 2014: Weather will be a prime area of focus by investigators of the disappearance of AirAsia flight QZ8501. The flight, an Airbus A320-200 manufactured in 2008 and powered by CFM 56 engines, deviated from its intended flight path due to weather conditions, according to reports from officials in Indonesia.
It’s presumed the airplane’s disappearance is an accident.
With these reports, investigators will put weather conditions at the top of their list of areas to probe. They will attempt to determine whether there was a high altitude upset due to turbulence that caused the plane to lose control; whether the plane was intact when it presumably crashed into the sea or whether it came apart in flight, and if so whether this possibility was caused by stresses beyond design limits. Investigators will attempt to determine whether the plane was struck by lightning, causing a chain of events leading to a crash.
Recovery of the flight data and cockpit voice recorders will be a priority. Data on these will go a long way toward telling investigators what happened and even potentially “why.” Recovery of the airplane itself and passengers will allow forensic analysis that will be important, such as whether the airplane broke up in flight and when passengers expired and due to what injuries and when—such as if passengers died on impact or from an explosive decompression if the airplane broke up in the air.
Weather, severe turbulence and lightning events have been known to precipitate crashes, although these are rare events, particularly at cruising altitudes. On June 1, 2009, Air France flight 447, an Airbus A330-200, crashed into the South Atlantic after flying into an area of severe turbulence and thunderstorms. The pitot tubes—which measure airspeed—froze over, beginning a chain of events in which the pilots stalled the airplane. The aircraft hit the ocean intact in a flat and minimal forward speed trajectory. Pilot error was determined to be the principal cause of this accident, with weather and the frozen pitot tubes being contributing factors.
As a matter of routine, investigators will also look at the following areas of inquiry, in no particular order:
As we post this, there are a few reports that some wreckage may have been spotted. Recovery of any wreckage and bodies from the waters may provide some initial clues as to what happened. Stress points on the airplane could indicate whether the plane was intact upon impact with the water and autopsies of bodies recovered could likewise tell whether passengers died from blunt force trauma or other injuries. If any passengers had life jackets on, this would suggest there was some warning before impact.
On other sites they call them “Airbus pitot tubes”, implying made by Airbus or at least very specific to Airbus. However as far as I can tell they are made by third party manufacturers (eg Thales) and there is nothing Airbus specific. My guess is that the cockpit automation in Airbus depends more heavily on the pitot data.
Is there any fundamental difference between non-Airbus and Airbus pitot tubes and their usage?
Two Boeing 757s had pitot-related crashes many years ago, one off Peru and one in the Caribbean. Any suggestions that pitot tube issues are strictly Airbus are just Airbus-bashing.
The 757s accidents were not due to iced up pitot tubes (plugged in two different ways)
737 did have issue that could easilyh have resulted in a crash
My problem with automation is nothing to do with Boeing or Airbus , its the fact that “sometime you feel like a nut and sometimes you don’t” approach.
Its the fact that’s its created a dependency and authorities are just now catching up on the fact that they are insanely complicated, unintuitive and they are wasting time practicing routine items they do all the time (landings ) when they need to practice the out of ordinary.
We have thing like the FLCH trap, there is a hole in it that does you in. Just when you need it, something odd is going on (Boeing heavily criticized ) or it reverts to pilot control (AF447, here, its all yours and good luck). Boeing allows you to violate the limits in auto, Airbus less so, both approaches have caused crashes.
My take is there should be regulation (i.e. an across the industry standardization of Auto Throttle) etc.
Good piloting gets around it, but not all pilots are good, most are middle of the road just doing their jobs. Sullenberger type are understandably all to rare.
While not ruling out any other possibilities, I would lean towards a weather related cause given the information at this time. However, historically, bad weather has been responsible for a multitude of in-flight upsets, frozen pitot tubes being just one.
Iced up AoA sensors (Air New Zealand/XL Airways flight 888T) is another. There have been several instances of engine flameouts due to ice/rain ingestion on CFM56s (e.g. TACA Flight 110). Icing of other structures, extreme winds, structural failure and lightning strikes are also possibilities. In particular, it is said that, while aircraft can tolerate usual lightning, they are not built to withstand “positive lightning” – a rare type, <5%, extremely potent and the conditions and altitude seem to be about right for this scenario.
Pingback: AirAsia Indonesia Flight 8501 Missing, with 162 On Board | Aviation Impact Reform
Scott Hamilton, the Boeing Aero Peru Accident was because the Static ports were all taped over with duct tape before a spray paint job and never removed before flight, thus screwing up the entire pitot-static system. ie. it was pure human negligence – not equipment failure
Yet in all the crashes with pitot static tubes (btw there was also one in 1972)…the primary cause is considered pilot error – as the pilots are responsible for determining which instruments are erroneous and which are not…