AF 447 Fin
The revelation, from a source with knowledge of the investigation into the loss of the aircraft carrying 228 passengers and crew, comes after bodies and wreckage from the A330 were recovered about 500 mi. northeast of the Fernando de Noronha archipelago (ATWOnline, June 5).
According to the Brazilian air force, the objects–the first recovered since the aircraft disappeared late on May 31–include a suitcase, an e-ticket, oxygen masks, a passenger seat, a backpack with a laptop and numerous personal effects.
Searchers now have a more positive fix on the location of the remains of the jetliner to help in their search for the cockpit voice and flight data recorders. But according to ATWOnline’s source, the amount of ACARS data has given the investigators “a pretty good idea” of what happened and finding the CVR and FDR may not be as critical to identifying the probable causes of the accident as first thought. It is understood that the aircraft transmitted 24 ACARS messages over 4 min.
The disclosure came as the French BEA confirmed that the A330 had not been fitted with new, improved pitot probes as per a routine Airbus service bulletin issued in 2007. In an unrelated move, in 2003 Airbus issued a notice calling for replacement of pitot probes on some A330s because of a manufacturing defect that could result in erroneous speed data. “The sensors had not been replaced,” BEA Director Paul-Louis Arslanian said.
Airbus on Friday issued a reminder to all operators of its aircraft regarding the correct actions to be taken when confronted with differing speed indications on its various aircraft models. The warning in the form of an Airline Information Telex said there was an indication of “inconsistency between the different measured
airspeeds” of AF447. The manufacturer added that “without prejudging the final outcome of the investigation, the data available leads Airbus to remind operators what are the applicable operational recommendations in case of unreliable airspeed indication.”
In the A330 manual, pilots also are warned to keep the aircraft within specified speed envelopes “so as to provide the best protection against the effect of gust on the structural limits.”
BEA has confirmed that AF447 was crossing a turbulent multicell convective area at the time of the ident and that failure maintenance messages were transmitted automatically from the aircraft.
French daily Liberation reported that the survey vessel Pourquoi Pas will reach the search area on about June 11 or 12. It was stationed in the Azores and had to collect advice on detecting the homing signal of the aircraft’s FDR from Cape Verde en route to the crash site. The FDR signal travels only 1,500 m underwater and the crash site is as deep as 4,000 m. A pinger locator could be lowered on a cable, but
that would slow the search. If the zone can be narrowed to a few km., the submarine Nautile carried aboard the Pourquoi Pas can detect a signal from 200 m.
From http://atwonline.com/news/story.html?storyID=16846
June 13th, 2009 at 12:17 am
I wonder why aircraft speed measurement only depends on the Pitot tube sensors. Is there no speed indication measured by GPS?
June 14th, 2009 at 3:21 pm
Hi Nick. Yes they do have GPS but of course that does not take into account wind. More sophisticated sensors are available as in the Spirit B2 Bomber but there are reasons related to conservative design and cost why they are not used.
Cheers
Michael
July 4th, 2009 at 1:20 pm
This photograph tells a very significant story it is the top half of the composite material tail surface it appears to have snapped off in the middle portion of the tail.
The entire composite tail came off the airbus that crashed several months after 9/11 in New York, when the pilot applied full rudder deflections. Very violent thunderstorms at the equator could have snapped off the top portion of this tail assembly during the flight making it impossible to control the aircraft, but allowing it to fly several more minutes.
Boeing has repeatedly rejected composite tail designs fearing such accidents.
July 5th, 2009 at 6:29 pm
Hi Chris. As more details comes to light it seems the expert money is on the fin being attached until the moment of impact based on what they have been able to deduce from the examination of the retrieved wreckage. I read the BEA report which is a bit reserved but seemed pretty confident about the fact AF447 was intact till the moment of impact. Maybe they had an upset and recovered only to have another upset which would not be hard in a pitch black cockpit with no reliable airspeed and maybe even suspect attitude information. Horrifying. I think composites can be made as strong as any metal once the issues are well understood and the Dreamliner (Becoming a nightmare for Boeing) is very much a composite aircraft.