What have we learned from the BEA dog and pony show in Paris this morning? Not much!
1. ACARS messages were sent every ten minutes to facilitate the investigators to track the route of the aircraft “certain degree of precision on route”.
2. There 24 messages received from the ACARS system with different failures. Fourteen of those messages were sent within the space of one minute, from 02:10UTC to 02:11UTC.
3. There was inconsistency between measured velocities and indications of systems failures including the autothrust and autopilot. Confirmed the information in the world that these messages had led investigators to detect a problem with the speed sensors.
4. BEA says the ACARS information was designed for maintenance and not investigative and therefore the failure of system only gave an indication as to the status of particular systems.
5. Take off weight 233T, fuel 68 T.
6. Weather. In the Intertropical convergence zone, there were Cumulonimbus clouds however nothing out of the ordinary. “Conditions normal” for this time of the year with “no anomalies”. At 02:15UTC the growth phase of the local cumulonimbus had already passed and the clouds were in the “lower end” of their cycle.
7. Ocean currents since the day of the accident have been drifting eastwards. The beacons transmit a 37.5kHz signal with an intensity of 160dB but, given they could be at 4,000m depth, the search teams on the surface would have to be “almost on top” of them to pick this up.
8. BEA “cannot guarantee” that the beacons have not separated from the recorders.
9. Even if the hypothesis of the explosion of a bomb can not be “excluded 100%,” it is not “very consistent” with the elements available to the investigators.
According to The Aviation Herald, the NTSB has accepted an invitation by the BEA to assist in the investigation and have dispatched Bill English as their representative joined by engineers from the FAA, General Electrics (manufacturer of the CF6 engines) and Honeywell.
The Chicago Tribune via AP reported that Air France has told its pilots in a memo obtained by The Associated Press that it is replacing instruments that affect flight speed in all its bigger jets. Investigators have focused on the equipment’s possible role in the disaster. I would be curious if any existing pilots were damaged in the Aug 04 ground accident.
The Air France memo says the company will finish replacing the instruments — known as Pitot tubes — in “coming weeks.” It does not say when the replacement process started and the company declined to comment on the advisory, saying it was meant for pilots only.
The L-shaped metal Pitot tubes jut from the wing or fuselage of a plane, and are heated to prevent icing. The pressure of air entering the tubes lets sensors measure the speed and angle of flight.
As noted on a pilot message board, a commenter asks:
Ice in the pitot tubes would REDUCE the amount of air getting through and cause the ASI’s to under-read, therefore the reaction of the auto-throttle would be to ADD power, not reduce it? However, the Airbus advisory and the press briefings seem to imply that the ASI ‘disagrees’ may somehow have caused the Flight 447 to fly too slowly, thus finally stalling speed?
Please explain to me how a General and Admiral can look at a wood pallet and ship buoy and claim “We have found the wreckage!” I honesty believe these jackass have ruined any changes of recovery operations by sending all resources to an area probably not even close to the plane’s location.
It appears however this military leadership duo will be in the news for a while longer. In the same AP report cited above:
Air Force Brig. Gen. Ramon Cardoso insisted Friday that at least some of the debris spotted from the air — an airplane seat, a slick of kerosene and other pieces — are from the plane that vanished Sunday with 228 people on board. The Brazilian air force also distributed images pinpointing where the material was found.
A French Defense Ministry official, speaking on condition of anonymity because he was not authorized to speak publicly on the matter, also questioned the Brazilian claims, saying French teams “cannot precisely confirm the zone where the plane went down.”
Looks like they are circling the wagons on Brazil’s military loose lips:
A statement issued jointly by Brazil’s Air Force and Navy said that to “avoid errors in interpretation” from now on any debris recovered in the area will only be divulged after being “positively identified” by Air France as coming from the ill-fated flight.
And finally, the French are sending in a submarine:
France is sending a submarine to the area to try to detect signals from the black boxes, said military spokesman Christophe Prazuck. The Emeraude will arrive next week, he said.
The North Equatorial Current (NEC) as represented by the Mariano Global Surface Velocity Analysis (MGSVA) is shown for this period. The NEC is the broad westward flow that is the southern component of the N. Atlantic subtropical gyre. It is fed by the Canary Current and its waters eventually end up in the Gulf Stream system, either via the Antilles current or through the Caribbean via the Guiana current.
The NEC found in the North Atlantic from about 7°N to about 20°N (see figure1; Schott et al, 2002). Fortified by the Atlantic trade wind belt, the NEC is a broad westward flowing current that forms the southern limb of the North Atlantic subtropical gyre (Bourles et. al. 1999b). The current originates from the northwestern coast of Africa, where it is fed mainly by the cooler waters flowing from the northeast Atlantic. As the NEC travels across the open ocean, it is joined by waters originating south of the equator thus entraining waters from the Southern Atlantic into the Northern Atlantic.
The details of these various pathways of cross-equatorial water exchange in the open-ocean remain unclear, in part because of the weak, meandering North Equatorial Counter Current (NECC), which lies south of the NEC. It is understood that the complex seasonal retroflection and recirculation current systems that straddle the equatorial region and the strong western boundary currents along the American shelf also play an important role in water-mass exchange with the NEC, however exactly how is not well understood (Arnault et al, 1999; Schott et al. 2002). Estimates by Onken (1994) suggest that wind-stress causes about 12 Sv of cross-equatorial transport to the north.
When the NEC approaches the shelf region of the Americas, its interaction with bottom topography and accompanying western boundary currents produce a complicated, seasonally variable flow regime, both laterally and vertically, that is still the source of continued investigations.
Standard Terms – Simple Explanation
Normal Law: Regular operating mode of the fly by wire (FBW) including all protections.
Alternate Law: Some of the protections in normal law, the regular operating mode, are dropped.
Direct Law: The controls (sidestick) inputs are converted into direct movements of control surfaces without computations or checks.
ADIRU: Air Data and Inertial Reference Unit provides air data (airspeed, altimeter, …) and positional data (attitude, position) to the instruments.
ISIS: Integrated Standby Instrument System is a completely independent, self contained system providing a third independent set of basic instruments (attitude indicator, altimeter, airspeed indicator) to the crew.
PRIM 1: Flight Control primary computer #1, three of them monitor each other, one of them controls the control surfaces as master.
SEC 1: Flight Control secondary computer #1, each of the two can control all airplane control surfaces in direct law and can become master in case of failure of all primary flight control computers.