they would be left to radio com and the aircraft had radio issues before departure).
Interesting - could you help out?...I don't recall reading this, (which just means, "I don't recall"); do we know what the nature of the issues was? Thanks!
I saw a post ages ago - quickly deleted, I think - which said that COM3 was inop when the plane departed. As a non pilot, I have no idea what COM3 is, but I was surprised the post elicited no interest at all.
Yes but you have to turn off the 3 adrs to get this bu sdp scale/gps alt.
What I'd like is a permanent aoa readout
cpdlcads,
Actually, the instrument exists and has been an available option for FBW Airbus's for at least 16 years, and probably since the introduction of the A320 in 1989. If you look at a cockpit photo you can even see the "blank" in the upper left corner of the Capt.'s instrument panel where the AoA indicator is meant to be fitted. The problem is not the lack of the instrument, just an unwillingness of the airline's to pay for an instrument that they don't consider necessary.
No, it is not and that is a problem to come to terms with.
It dependes on what is meant by "validation".
The iru contains a 3 axis gyro triad, either mechanical platform or l@ser ring, but also most importantly, accelerometers. The gyro triad can only provide attitude info but the accelerometer and gyro data via some fancy math gives absolute position on the earth's surface. Integrate acceleration once to get speed, twice to get distance travelled.
There may well be cross coupling between systems that measure similar parameters. Air data info may be mixed in to the IRU to provide cross referencing, fault detection etc. For example: detection of an unexpected transient between iru and adu calculated air speed that doesn't stabilise within defined time limits, points to ?...
As a non pilot, I have no idea what COM3 is, but I was surprised the post elicited no interest at all.
VHF COM3 is not the main communications radio. It is used by ACARS and by the 3rd pilot when communicating with company. When out of VHF range, which AF447 was, ACARS automatically switches over to SATCOM. Just like the LAV ACARS message, there would be no real interest in the snag - it's a non-issue.
AIRBUS is expected to face calls to ground its worldwide fleet of long-range airliners tomorrow when French accident investigators issue their first account of what caused Air France Flight 447 to crash off Brazil on June 1.
It is believed that the accident bureau will report that faulty speed data and electronics were the main problem in the disaster, which killed 228 people.
The European Aviation Safety Agency (EASA) is likely to be asked why it had never taken action to remedy trouble that was well known with the Airbus 330 and 340 series. Nearly 1,000 of the aircraft are flying and until last month, no passenger had been killed in one.
"EASA has a legal and moral obligation to get to the bottom of this problem now," said James Healy-Pratt of Stewarts Law in London. "If there is a defective system and the aircraft is unsafe then it should be grounded."
Stewarts Law, which specialises in aviation, is representing the families of 20 victims of the Air France disaster.
Only 11 bodies of the 50 recovered from the Atlantic have been identified. They include Captain Marc Dubois, 58, who is believed to have been resting when his two co-pilots lost control of the aircraft in a storm.
Suspicion over the air data systems on the Airbus 330 and 340 series has increased after the disclosure that the aircraft had experienced 36 episodes similar to the one that brought the aircraft down as it flew from Rio de Janeiro to Paris.
Airbus first reported problems with the speed sensors - known as pitot tubes - in 1994. The company advised remedies, but no mandatory action was taken.
Last weekend, the US National Transportation Safety Board began looking into two incidents in which Airbus A330s flying from the US suffered critical episodes apparently similar to that of the Air France flight.
The fate of the aircraft would probably have remained a mystery had it not automatically transmitted data back to the Air France base.
In the final four minutes, they told a story that was familiar to the airline. Ice particles or water had blocked the three pitot tubes. This upset the air data computers, which in turn caused the automatic pilot to disconnect. The pilots would have had to fly manually in near-impossible conditions.
This paper discusses jet engine powerloss and damage due to ingestion of ice particles. In the mid-90s several commercial airplane jet engines experienced more frequent powerloss in ice particle conditions, resulting in a focused investigation, and a greater awareness that led to recognition of similar events on other aircraft.
Since the mid-90s, events have been more numerous, and costly, and have generated greater industry interest. These events have been predominately associated with flight at high altitude near deep convective systems, often in tropical regions...
"EASA has a legal and moral obligation to get to the bottom of this problem now," said James Healy-Pratt of Stewarts Law in London. "If there is a defective system and the aircraft is unsafe then it should be grounded."
Stewarts Law, which specialises in aviation, is representing the families of 20 victims of the Air France disaster.
If that gross misunderstanding of how continuing airworthiness actually works is indicative of their specialism, then I'm not very impressed. Of course, that last sentence casts a fair degree of doubt on their status as a disinterested commentator on the topic.
In the final four minutes, they told a story that was familiar to the airline. Ice particles or water had blocked the three pitot tubes. This upset the air data computers, which in turn caused the automatic pilot to disconnect. The pilots would have had to fly manually in near-impossible conditions.
Reading between the lines, I have to wonder if Airbus had seen the same sequence of ACARS messages in other non-fatal upsets.
Sorry if this info was posted before but it is not possible to me to keep up with this thread size.
Before this AF447 crash Airbus had issued an OPTIONAL pitot change, it was not a recall. Since long Airbus had warned operators of this ADR PITOT thing and as I hear my friends on A330 are flooded with stories of speed loss in cruise and I wonder if FAA and JAA were also aware of this, its consequences allied with the fact that under total ADR failure the angle of attack sensor is also inhibited putting the pilots clueless
The call for grounding is no surprise, nor is it a surprise to learn who seems to be leading the call.
Though we know differently, the grounding of an aircraft is a flight safety matter, not a legal, economic or political matter.
Such a serious undertaking is for those who do this work including flight safety specialists and those who certify airliners, not "specialists" in the prosecution of aviation accidents whose goal is winning large quantities of money for clients not the enhanced safety of passengers, and who use as their primary weapon the media in which whipped emotion, not knowledge, advances their goal.
We have seen here and elsewhere, claims that "vertical stabilizers come off Airbus airplanes too easily".....-sweeping generalizations that pitot systems are unreliable and that one "solution" is to mount pitot heads nearer the middle of the fuselage away from where the ice hits first or to mount them behind protective covers. Such lack of understanding and knowledge is precisely what such lawyers value most - it is most easily manipulated.
The goal of this meeting should be to enlighten and to state what new information has been found, if any. The pressure to state preliminary causes may be the 30-day requirement but that should not provide a platform for such calls turning what is a serious responsibility into a media circus.
Whether the case for grounding will be proven cannot be presently determined. Any decision would have to be substantiated by a very high standard of evidence. That is the point that should be made in response to any call to ground the aircraft.
Though we know differently, the grounding of an aircraft is a flight safety matter, not a legal, economic or political matter.
Are you sure you can discard the factor "economic" (and BTW .. economic can be linked with "politic")so surely from a decision or not to ground a type of aircraft ? It was not easy to ground the Concorde .. and in fact this plane was a economic disaster in exploitation .. so it was not a great lost for AF and BA .. just a lost of "prestige".. For the Airbus type .. it's completely different. Imagine all the A330 and 340 grounded ... Who will have the "balls" for take such decision if necessary ?
Per the guidance material for continuing airworthiness in EASA (ACJ39.3(b)(4) is the latest I have here) the probability of a catastrophic event which would require immediate grounding of an affected fleet is 2X10^-6 i.e. one event in 500,000 flight hours.
The current A330 fleet is approx 600 aircraft. Assuming about 50% untilization (which seems to be about the rate for the accident aircraft since delivery) that would imply the fleet is accruing flight hours at about 200,000 fh/month.
There would therefore have to be an expected accident rate of the order of one per three months to require grounding. Since the historic rate is one per ... well, since service entry, it seems clear that the hazard is not sufficient to require grounding by any reasonable assessment of the figures, unless there is something very specific going on (like a production batch issue, in which case only that batch would be impacted of course)
An 330 flying into a horrendous storm and crashing due to potential icing of the Pitot tubes and super freezing ice on other areas of the airframe, (some suggest engine ingestion) caused by flight into CB. Surely this cannot be enough to ground the entire 330 fleet. An AD suggesting caution in CB, I can understand.
The DC 10 was a totally different problem and should not be compared in anyway.
June 29, 1994
Boeing mystified over 'violent' 747 stall
Boeing has failed to find the cause of an incident in which a Singapore Airlines (SIA) Boeing 747-400 stalled while at cruising altitude over Bucharest on a Singapore-Heathrow flight (Flight International, 3-9 November, 1993).
Independent reports from two private pilots, who were passengers, subsequently stated that the incident was far more violent than Flight International's report or the SIA statement at the time indicated.
The incident involved cockpit audible stall-warnings which could be heard in the upper-deck cabin, then buffeting, followed by two separate stalls during which the aircraft descended rapidly, losing "several thousand feet" in controlled airspace. SIA would admit only to an unexplained loss of airspeed followed by a pilot decision to descend to increase speed.
One of the pilot passengers reported that some flight attendants were thrown off their feet and that drinks hit the cabin ceiling.
An SIA source says that the pilot and co-pilot were puzzled by an apparent disparity in the airspeed readings of their respective instruments - one of which appeared to be receiving "frozen" speed data. The incident occurred as they tried to decide which instrument was giving correct readings.
Boeing says: "Working with the customer airline and equipment manufacturers, we performed tests on aircraft equipment which we thought might have contributed to this anomaly. We examined the air- data computer, pitot-static probe systems and other equipment. Nothing was discovered that would explain the anomaly.
"The equipment was removed and replaced, pitot-static lines drained and flushed, and the aircraft returned to service. There has been no recurrence." Boeing adds: "We're still working with the airline to see whether we can determine the cause. We have not been informed of other instances like this."
from: Flight International
(apologies if this is off-topic, but it does cite a possible pitot issue)
May I respectfully suggest that the anticipated official report presents a great opportunity to freeze this thread and start another one. Ideally starting the new thread with a link to the official report.
What is the general feeling? I feel that 132 pages is already long enough.
Regards, Peter
... and many thanks to all the informative posters who have enlivened this investigation so far.
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