Varie
INCIDENTE TURKISH AIRLINES A SKCHIPHOL AMSTERDAM
La Task Force della Fondazione 8 ottobre, venuta in possesso del
"preliminary report" relativo all´incidente avvenuto in atterraggio ad
Amsterdam al velivolo turco, volo TK1951, viste le numerose illazioni in
merito, ritiene di fare cosa utile pubblicando le prime risultanze ed
obiettività emerse dalla analisi dei registratori di volo.
Sicuramente il percorso per comprendere ed approfondire le cause dell´
incidente sarà ancora lungo, ma queste prime notizie ufficiali, sono un
supporto importante per iniziare a fare chiarezza ed evitare il proliferare
di "voci" ed affermazioni non corrette, che non aiutano l´impegno per la
Sicurezza del Volo.
La T.F. della Fondazione 8 ottobre 2001.
Today <4 March 2009>, the Dutch Safety Board has issued a warning for airline manufacturer Boeing and presents its initial findings regarding the terrible accident involving the Boeing 737/800, Turkish Airlines flight. This accident claimed the lives on nine people (5 passengers and 4 crew) and 80 passengers were injured. Twenty eight of those injured are still hospitalised.The Boeing was en route from Istanbul to Schiphol (on Wednesday 25 February 2009) and was due to land at Schiphol at 10.40. The Boeing had had a regular flight and no problems had been experienced until just before the approach. There were three people in the cockpit, the captain was located on the front, left hand side. On the right hand side there was the first officer, for whom this was a training flight. (The first officer had all appropriate qualifications). There was also an extra first officer in the centre of the cockpit. The crew made contact with air traffic control (Amsterdam Radar) at 10.04 and was transferred to the tower at Schiphol - for the landing – at 10.14. The tower then gave the Boeing permission to land on the Polderbaan 18R The Polderbaan was approached according to fixed procedures, without any delay, and the Boeing was then given permission to decrease its altitude to 2000 feet (about 700 meters) and begin its descent to the Polderbaan. This descent takes place with the help of the automatic pilot, as is normal with Turkish Airlines (this method can be utilised by everybody, as can a manual landing). The voice recorder and the black box, both of which are in the hands of the Safety Board, show that an irregularity occurred during the descent, at 1950 feet. At a height of 1950 feet the left radio altimeter suddenly indicated a change in altitude – from 1950 feet to - 8 feet - and passed this onto the automatic pilot. This change had a particular impact upon the automatic throttle system which provides more or less engine power. The radio altimeter normally measures the altitude of the plane above the ground very accurately and can start registering this from 2500 feet. As already mentioned, this radio altimeter is very significant for providing the appropriate power for an automatic landing. A Boeing is fitted with two radio altimeters, a left one and a right one. The black box has shown that this deviation only occurred in the left radio altimeter. The voice recorder has shown that the crew were notified that the left radio altimeter was not working correctly (via the warning signal “landing gear must go down”). Provisional data indicates that this signal was not regarded to be a problem. In practice, the plane responded to this sudden change as though it was at an altitude of just a few meters above the Polderbaan and engine power was reduced. It seems that the automatic system – with its engines at reduced power – assumed it was in the final stages of the flight. As a result, the aircraft lost speed. Initially the crew did not react to the issues at hand. As a result of the deceleration, the aircraft´s speed was reduced to minimum flying speed (stalling situation) and warning signals (the steering column buzzes at an altitude of 150 metres) were given. The black box shows that full power was then applied immediately. However, this was too late to recover the flight, the aircraft was too low and, consequently, the Boeing crashed 1 kilometre short of the runway. The black box – which can register 25 hours of flying time and which, in this case, covered 8 flights- showed that this problem had occurred twice previously in a similar situation, before landing. The aircraft initially hit the ground with its tail and then the undercarriage followed. The forward speed was about 175 km per hour upon impact. An aircraft of this weight should normally have a speed of 260 km per hour for landing. The aircraft came to a rapid halt (after about 150 m) as a result of the arable land being made up of boggy clay. The braking caused by the ground meant that the aircraft broke into two pieces; the tail broke off and the aircraft’s hull ruptured at business class. The landing gear broke off, in accordance with its design. This also applied to the two engines. The full power and the sudden braking resulted in both engines continuing forwards for a further 250 meters. Most of the fatally wounded victims were located near the rupture, in business class, and the three crew members in the cockpit died as a result of the enormous braking forces, partially caused by the embedded nose-wheel and the forward movement of the aircraft. The section that remained most intact was situated around the wings. On board the plane there were 127 passengers and 7 crew, of whom 28 are still hospitalised. The Board’s investigation will now focus fully on the workings of the radio altimeters and the connection to the automatic throttle (automatic steering system). Weather conditions, particularly visibility through the low cloud base and the mist, probably meant that the Polderbaan was not yet visible at the height at which the descent was commenced. The Safety Board board will be assisted in its investigation and its attempts to ensure lessons are learnt by the following organisations:
• the National Transportation Safety Board
• Bureau d’Enquetes et d’Analyse (BEA)
• Aviation Accident Investigation Branche (AAIB)
• Directorate General of Civil Aviation (Turkse Rijksluchtvaartdienst, DGCA)
• Boeing
• Turkish Airlines
• The engine manufacturer, CFM
• Inspectie Verkeer en Waterstaat (IVW) [Traffic and Waterways Inspectorate]
• Federal Aviation Agency (FAA, American Civil Aviation Authority)
• Vereniging van Nederlandse verkeersvliegers [Association of Dutch Commercial Pilots]
• Nederlandse vereniging voor cabinepersoneel [Dutch Association for Cabin Personnel]
Internationally, both the ICAO and the EU stipulate that involved parties may take part in the
Board’s investigation (party system). The investigation itself, however, is supervised by and remains the Board’s responsibility. The Board has also received a great deal of data from the Public Prosecutor for its investigation. Furthermore, there have been content-based contributions from a great many police organisations. The National Police Force, particularly all staff from the National Team of Forensic Investigation who are responsible for the forensic work at the location itself, the Aviation Police, who took all the aviation photographs, and the National Traffic Assistance team who helped the Board to measure the location of the accident. The Public Prosecutor took possession of the aircraft and, as a result, responsibility for guarding it lay entirely with them. Police officers from all over the country were drafted in for this purpose. We are extremely grateful for their outstanding and meticulous work and for guarding the aircraft. There was a misunderstanding regarding the use of the data from the cockpit voice recorder and the flight recorder (black box). It is established, in Dutch law, that the Public Prosecutor may only have access to this data if there is a question of abduction, terrorism, murder or manslaughter. In such a situation, the Safety Board is also legally obliged to hand over this data to the Public Prosecutor. In principle, there are two investigations being carried out into the accident.
• The judicial investigation. The search for punishable facts and the use of these to hold those responsible to account.
• The independent investigation. This investigation focuses fully on finding out what happened so that lessons can be learnt. There is always some tension between the two investigations. Within criminal law you may be silent. Nobody needs to contribute to his or her sentence. With the independent investigation, however, you want to ensure that everything is said. For this reason, the reports from the Board may not be used as evidence in lawsuits. From today onwards, the investigation by the Board will concentrate on two subjects:
The technical investigation will focus on the role of the automatic pilot, the automatic throttle system and the connection to the radio altimeter. .
Alongside the aforementioned technical investigation, the focus will also be on the management of the crisis.How was the disaster dealt with and what can be learnt from this. This investigation will also focus on the passenger list. The recovery of the wreckage will probably take place at the end of this week. The aircraft will be taken to another location for – possible – further investigation. The Board is of the opinion that extra attention is needed for the role of the radio altimeter when using the automatic pilot and the automatic throttle system. The Board has issued a warning for Boeing today requesting extra attention to a part of a manual for the Boeing 737, in which is stated that in case of malfunction of the radio altimeter(s), the automatic pilot and throttle system that are connected to this may not be used for approach and landing. The Board would like Boeing to consider an investigation into whether this procedure is also applicable during flight. With the exception of the malfunction of the left radio altimeter the investigators of the Dutch Safety Board have not yet found any irregularities.
Task Force Tecnica della Fondazione 8 Ottobre 2001 - 06/03/2009
Risposte
- Facendo seguito alla pubblicazione del Rapporto Preliminare sull´incidente di Amsterdam al Boeing 737 turco, pubblichiamo anche il messaggio, molto significativo, del costruttore Boeing, inviato a tutti gli operatori di 737, a seguito delle prime evidenze emerse dalla lettura del FDR (Flight Data Recorder, Registratore dei dati di Volo) sulla dinamica dell´incidente.
Desideriamo sottolineare che la divulgazione di informazioni relative ad una inchiesta in corso, è consentito solo quando le stesse sono ritenute di grande rilievo ai fini della Sicurezza del Volo, tanto da richiedere una informativa immediata.
Questo è stato, evidentemente, ritenuto uno di quei casi.
Tutta la flotta di 737 ne è interessata.
Viste le circostanze, proseguiremo nella nostra opera di aggiornamento, nel caso in cui emergano ulteriori elementi di grande ed immediato interesse per la Sicurezza del Volo, fino alla pubblicazione del Rapporto Finale.
La Task Force della Fondazione 8 ottobre 2001.
Subject: 737-800 TC-JGE Accident at Schiphol Airport, Amsterdam - 25 February 2009
FROM: THE BOEING COMPANY
TO: MOM [MESSAGE NUMBER:MOM-MOM-09-0063-01B] 04-Mar-2009 05:29:01 AM US PACIFIC TIME Multi Operator Message
This message is sent to all 737-100,-200,-300,-400,-500,-600,-700,-800,-900,-BBJ customers and to respective Boeing Field Service bases, Regional Directors, the Air Transport Association, International Air Transport Association, and Airline Resident Representatives.
SERVICE REQUEST ID: 1-1228079803
ACCOUNT: Boeing Correspondence (MOM)
DUE DATE: 10-Mar-2009
PRODUCT TYPE: Airplane
PRODUCT LINE: 737
PRODUCT: 737-100,-200,-300,-400,-500,-600,-700,-800,-900,-BBJ ATA: 3400-00
SUBJECT: 737-800 TC-JGE Accident at Schiphol Airport, Amsterdam - 25 February 2009
REFERENCES: /A/ 1-1222489391 Dated 25 February 2009
Reference /A/ provides Boeing´s previous fleet communication on the subject event. The US NTSB, FAA, Boeing, the Turkish DGCA, the operator, the UK AAIB, and the French BEA continue to actively support the Dutch Safety Board´s (DSB) investigation of this accident.
The DSB has released a statement on the progress of the investigation and has approved the release of the following information.
While the complex investigation is just beginning, certain facts have emerged from work completed thus far: -
To date, no evidence has been found of bird strike, engine or airframe icing, wake turbulence or windshear.
There was adequate fuel on board the airplane during the entire flight.
Both engines responded normally to throttle inputs during the entire flight.
The airplane responded normally to flight control inputs throughout the flight.
The Digital Flight Data Recorder (DFDR) data indicates that the crew was using autopilot B and the autothrottle for an ILS (Instrument Landing System) approach to runway 18R at Amsterdam Schiphol airport. During the approach, the right Low Range Radio Altimeter (LRRA) was providing accurate data and the left LRRA was providing an erroneous reading of -7 to -8 feet. When descending through approximately 2000 feet the autothrottle, which uses the left radio altimeter data, transitioned to landing flare mode and retarded the throttles to the idle stop. The throttles remained at the idle stop for approximately 100 seconds during which time the airspeed decreased to approximately 40 knots below the selected approach speed.
The two LRRA systems provide height above ground readings to several aircraft systems including the instrument displays, autothrottle, autopilots and configuration/ground proximity warning. If one LRRA provides erroneous altitude readings, typical flight deck effects, which require flight crew intervention whether or not accompanied by an LRRA fault flag, include:
Large differences between displayed radio altitudes, including radio altitude readings of -8 feet in flight.
Inability to engage both autopilots in dual channel APP (Approach) mode
Unexpected removal of the Flight Director Command Bars during approach
Unexpected Configuration Warnings during approach, go-around and initial climb after takeoff
Premature FMA (Flight Mode Annunciation) indicating autothrottle RETARD mode during approach phase with the airplane above 27 feet AGL. There will also be corresponding throttle movement towards the idle stop. Additionally, the FMA will continue to indicate RETARD after the throttles have reached the idle stop
Boeing Recommended Action - Boeing recommends operators inform flight crews of the above investigation details and the DSB interim report when it is released. In addition, crews should be reminded to carefully monitor primary flight instruments (airspeed, attitude etc.) and the FMA for autoflight modes. More information can be found in the Boeing 737 Flight Crew Training Manual and Flight Crew Operations Manual.
Operators who experience any of the flight deck effects described above should consult the troubleshooting instructions contained in the 737 Airplane Maintenance Manual. Further, 737-NG operators may wish to review 737NG-FTD-34-09001 which provides information specific for the 737-NG installation. Initial investigations suggest that a similar sequence of events and flight deck indications are theoretically possible on the 737-100/-200/-300/-400/-500. Consequently the above recommendations also apply to earlier 737 models.
Operators will be notified if further action is recommended.
Jack Trunnell Director - Fleet Support Engineering Technical Customer Support Commercial Aviation Services The Boeing Company
Task Force Tecnica della Fondazione 8 Ottobre 2001 - 06/03/2009
- Un ringraziamento alla task force della Fondazione per aver documentato a dovere i primi risultati dell´inchiesta, risultati che hanno spazzato via una congerie di ipotesi che, a livello meidatico, sono state fatte nei giorni scorsi, senza avere un minimo di cognizione di causa.
Con la dovuta prudenza, alla luce di queste prime note, mi sentirei di affermare che l´enorme progresso della tecnologia nel campo dell´aviazione deve sempre accompagnarsi con un responsabile comportamento umano nell´utilizzo degli ottimi mezzi a oggi disposizione degli operatori aerei.
Avv. Antonio Alessio Boccia
Avv. Antonio Alessio Boccia - 10/03/2009
