Air Algérie AH5017 (operato da Swiftair) si schianta al suolo


Air Algerie cockpit voice recorder damaged on impact

French air accident investigators have read the flight data recorder (FDR) of the Boeing MD-83 that crashed in Mali while operating for Air Algerie, but work is continuing on the cockpit voice recorder (CVR), which was damaged on impact.
Flight AH5017 was operating from Ouagadougou in Burkina Faso to Algiers on July 24 when it crashed in the Gossi region of northeastern Mali, near the border of Burkina Faso. The wreckage was found in a disintegrated state and there were no survivors among the 112 passengers and six crew on board.
While the Republic of Mali is leading the investigation, France’s Bureau d'Enquêtes et d'Analyses (BEA) has been brought in to provide technical assistance. BEA said two of its investigators traveled to the scene July 25, where the CVR and FDR were both recovered. These were transported to France and officially handed to the director of the BEA on Monday.
“Work on opening them began immediately. BEA investigators were quickly able to read out the data from the FDR. Work on decoding and analyzing the data in detail will now start, with members of the Malian Commission of Inquiry. The CVR was damaged in the impact. Work is continuing on this recorder in order to extract data from it,” BEA said.
It added that next steps and initial findings would be communicated by the Malian authorities.
While the cause of the crash remains unknown, weather is being considered. French officials said they believe the aircraft broke up only upon impact with the ground, rather than in mid-air.
The aircraft was an MD-83, chartered by Air Algerie from Spanish company Swiftair (serial number MSN53190, registration EC-LTV). It was manufactured Aug. 20, 1996 and was powered by Pratt & Whitney JT8D-219 engines. Swiftair said it was equipped with Cat III, BRNAV, FMS/GPS, TCAS II and RVSM.

atwonline
 
Ancora incongruenze tra la BEA e Swiftair sul passenger manifest:


On Jul 29th 2014 the BEA reported in their weekly bulletin, that the investigation is being led by the Accident Investigation Board of Mali, who have requested assistance from the BEA. The aircraft carried 112 passengers including 54 French Nationals and 6 crew.

On Jul 29th 2014 the passenger manifest as published by Swiftair as well as Air Algerie still lists 110 passengers and 6 crew.

avherald
 
Information on 7 August 2014
published with the agreement of the President of the Mali Commission of Inquiry

The Commission of Inquiry set up by the Republic of Mali brought together representatives of the following States at the BEA:
◾Algeria, Burkina Faso, France, Mali, Spain, United States.


Working sessions involving around twenty aviation Safety Investigators took place at the BEA in the presence of the President of the Mali Commission of Inquiry and the Director of the BEA. These sessions made it possible to determine how the investigation will be organised, to review progress on the information available and to decide on the work to be launched as a priority.

The investigation is organised around three working groups:
◾The Aircraft Group is initially tasked with producing a graphic representation of the accident site wreckage and deducing from this a probable final trajectory (angle and attitude on impact).
◾The Systems Group is prioritising a reconstitution of the history of the flight, based on the recorded flight data, radio communications data and information on meteorological conditions.
◾The Operations Group will initially collect Air Traffic Control information (radar and radio communications), meteorological information and the flight dossier on departure from Ouagadougou.

These three groups started work immediately.

In the context of the Systems Group, work on the flight recorders has continued.

The readout of some flight parameters from the Flight Data Recorder (FDR) made it possible to recreate a first image of the aeroplane’s flight path. Other parameters have yet to be validated. Finally, additional calculations must be performed using a behaviour and performance model of the aeroplane and its engines, in order to further define the scenario of the event, in particular the end of the flight.

The magnetic tape in the Cockpit Voice Recorder (CVR), which was damaged, was repaired and read out. Unfortunately, the recordings that it contains are unusable, due apparently to a recorder malfunction, with no link to the damage that resulted from the accident. Analysis continues to try to find a means of extracting some information, but is it not possible to predict the outcome of this approach.

The absence of usable data from the CVR at present underlines the need to collect all data on communications that the crew may have made with organisations on the ground or with other aircraft.

The aeroplane’s flight path as it was reconstituted from the FDR data, superimposed over a satellite image of the cloud mass present on the day of the accident, shows a normal climb and start of cruise, with some moderate route changes that are typical of a strategy to avoid any stormy developments.

◾The aeroplane took off from Ouagadougou at 1h151. It climbed and reached flight level 310 at 1h37.
◾At flight level 310, the aeroplane stabilised in cruise at a speed of about 280 kt.
◾Around two minutes after the start of cruise, while remaining at flight level 310, the speed dropped progressively.
◾The aeroplane began descending progressively and the speed continued to drop down to about 160 kt.
◾The aeroplane then turned left and quickly lost altitude, with large changes in pitch and bank. The rotation to the left continued until the end of the recording. The last recorded point, 1h47mn15s, corresponds to an altitude of 1,600ft, a speed of about 380 kt and an extremely high descent speed.


An interim report will be published in mid-September by the President of the Mali Commission of Inquiry.

http://www.bea.aero/en/enquetes/flight.ah.5017/flight.ah.5017.php

PowerPoint qui:
http://www.bea.aero/en/enquetes/flight.ah.5017/presentation.commission.mali.070814.en.pdf
 
TW 843 ha detto:
The magnetic tape in the Cockpit Voice Recorder (CVR), which was damaged, was repaired and read out. Unfortunately, the recordings that it contains are unusable, due apparently to a recorder malfunction, with no link to the damage that resulted from the accident. Analysis continues to try to find a means of extracting some information, but is it not possible to predict the outcome of this approach.

The absence of usable data from the CVR at present underlines the need to collect all data on communications that the crew may have made with organisations on the ground or with other aircraft.
Clicca per espandere...
Letto solo ora questo passaggio, bella sfiga che sicuramente non aiuta a capire le cause e dinamiche.
 
A first report from investigators probing the crash of Air Algérie flight AH5017 said Saturday that the cause of the tragedy that killed 116 people was still unknown and that all possibilities were still being considered, including terrorism.

"At the moment... nothing is telling us that we can rule out or confirm terrorism. We are not favouring any line of inquiry," Bernard Boudaille, of France's Bureau of Investigations and Analyses (BEA) air safety agency, told reporters in the Malian capital Bamako.

Flight AH5017 took off from Ouagadougou in Burkina Faso bound for Algiers but crashed in the Mali desert on July 24, killing all 116 people on board.

The pilots of the doomed McDonnell Douglas 83 airliner had asked aviation authorities if they could turn back to Burkina Faso as bad weather struck.

Presenting the initial report into a probe into the tragedy, Boudaille and the head of Mali's civil aviation accident commission, N'Faly Cisse, said the crew was experienced, not hampered by fatigue and was prepared to deal with the difficult weather conditions.

Nearly half of the victims were French citizens. Other passengers had come from Burkina Faso, Lebanon, Algeria, Spain, Canada, Germany and Luxembourg.

Investigators said in August that the voice recordings taken from the cockpit were “unusable”.

"The tape was a little bit damaged,” Rémi Jouty, the head of France's BEA air safety agency, told journalists. “The BEA laboratory was able to restore the tape. Unfortunately the recordings are, so far, unusable.”

(FRANCE 24 with AFP)

Date created : 2014-09-20
 
Da Avherald:

By Simon Hradecky, created Thursday, Apr 2nd 2015 18:47Z, last updated Thursday, Apr 2nd 2015 18:53Z

On Apr 2nd 2015 the French BEA released further preliminary information based on computations and assessments by the engine manufacturer.

The BEA reported that about 2 minutes after the aircraft levelled off at FL310 the EPR indications of the right hand engine became erroneous, another 55 seconds later the EPR indications of the left hand engine also became erroneous. These erroneous EPR indications are likely the result of pressure sensors located at the engine inlet having iced up.

Analysis of the data suggests that the related anti ice systems had not been activated during climb and cruise.

As result of the blocked pressure sensors and resulting incorrect EPR data autothrottle limited the thrust available at an value that was insufficient to maintain speed. Over 5:35 minutes the aircraft's indicated speed reduced from 290 to 200 knots, the angle of attack increased beyond stall. 20 seconds after the aircraft entered stall the autopilot disconnected causing the aircraft to abruptedly roll left to a bank angle of 140 degrees and a drop of the nose by about 80 degrees. The recorded data suggest that there has been no stall recovery done by the crew. Following the roll and nose down there are control inputs recorded to roll the aircraft right and pull the nose up.

The BEA reported that there had been 2 similiar occurrences before: On Jun 4th 2002 a Spirit Airlines MD-82 registration N823NK was in flight at FL330 in daylight out of clouds when power was lost in both engines due to overestimated EPR values due to ice crystals blocking both pressure sensors at the engine inlet, the crew descended the aircraft, activated the anti-ice systems and continued to destination, and on Jun 8th 2014 a Swiftair MD-83 registration EC-JUG was in level flight at FL330 in daylight above cloud layer, when the crew noticed the problem, engaged the anti-ice clearing the problem before reaching stall and continued to destination.

The investigation continues, the final report is estimated for December 2015.
 
Domanda da profano: per quale motivo alcuni equipaggi si sono accorti dello scadimento della velocità in tempo utile, e altri no?
Inoltre, cosa significa "there has been no stall recovery done by the crew"? Possibile che nel buio non si siano accorti nemmeno dello stallo?
 
Visto che il CVR non è stato recuperato, è impossibile sapere se l'equipaggio ne era al corrente o no
Forse erano proprio così occupati dall'osservare l'EPR dei motori o capire perchè la velocità stava scendendo, che non hanno reagito a tempo

La procedura di stallo non è stata fatta, infatti "Following the roll and nose down there are control inputs recorded to roll the aircraft right and pull the nose up."
Invece di abbassare il muso e cercare di recuperare velocità, stavano cercando di livellare le ali e rialzare il muso
 
Negli ultimi anni, in 2 casi un aeromobile entra in stallo e gli equipaggi o non se ne accorgono, o,qualora se ne fossero accorti, non eseguono alcuna manovra atta a recuperare il corretto assetto.
oltre a questo caso, anche AF 447.
a questo punto , mi chiedo se è cosi difficile riconoscere uno stallo su di un liner, che, mi rendo conto non è un cessnino, e se gli equipaggi sono correttamente addestrati
 
Nessuno ha detto che non sia stato riconosciuto
Per poter uscire dallo stallo devi comunque livellare le ali per ridurre il carico alare, e dopo la cadura d'ala erano a 80° ND, quindi l'energy gain è stato comunque rapidissimo, magari portando proprio ad un secondary stall
Non ci sono poi dettagli riguardanti Stick Shaker e Stick Pusher, di cui l'MD80 è dotato
Ci vorrebbe qualche dettaglio in più per poter approfondire la questione
 
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