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Air France Flight 447 (AF447/AFR447) was a scheduled passenger flight from Rio de Janeiro, Brazil to Paris, France, which crashed on 1 June 2009. The Airbus A330, operated by Air France, entered an aerodynamic stall from which it did not recover and crashed into the Atlantic Ocean at 02:14 UTC, killing all 228 passengers, aircrew and cabin crew aboard the aircraft. While the Brazilian Navy removed the first major wreckage and two bodies from the sea within five days of the accident, the initial investigation by France's Bureau d'Enquêtes et d'Analyses pour la Sécurité de l'Aviation Civile (BEA) was hampered because the aircraft's black boxes were not recovered from the ocean floor until May 2011, nearly two years later.〔 ((Original French version )).〕 The BEA's final report, released at a news conference on 5 July 2012, concluded that the aircraft crashed after temporary inconsistencies between the airspeed measurements – likely due to the aircraft's pitot tubes being obstructed by ice crystals – caused the autopilot to disconnect, after which the crew reacted incorrectly and ultimately led the aircraft to an aerodynamic stall from which they did not recover.〔〔 The accident was the deadliest in the history of Air France. It was also the Airbus A330's second and deadliest accident, and its first in commercial passenger service. ==Accident== The aircraft departed from Rio de Janeiro-Galeão International Airport on 31 May 2009 at 19:29 local time (22:29 UTC),〔Final Report, page 21, section 1.1〕 with a scheduled arrival at Paris-Charles de Gaulle Airport at 10:03 the following day. The last voice contact with the aircraft was at 01:35 UTC, 3 hours and 6 minutes after the 22:29 UTC departure, when it reported that it had passed waypoint INTOL (), located off Natal, on Brazil's north-eastern coast.〔 The aircraft left Brazilian Atlantic radar surveillance at 01:49 UTC.〔(Final Report ), p. 49: "The radar data show that AF 447 passed over the SALPU point at 1 h 49 min, the last recorded radar point corresponding to the limit of radar coverage (...)"〕 The Airbus A330 is designed to be flown by a crew of two pilots. However, because the 13-hour "duty time" (flight duration, plus pre-flight preparation) for the Rio-Paris route exceeds the maximum 10 hours permitted by Air France's procedures, Flight 447 was crewed by three pilots: a captain and two first officers.〔BEA first interim report, section 1.17.2.3 "Air France procedures"〕 With three pilots on board, each of them can take a rest during the flight, and for this purpose the A330 has a rest cabin, situated just behind the cockpit.〔BEA first interim report, section 1.17.2.2〕 In accordance with common practice, the captain had sent one of the co-pilots for the first rest period with the intention of taking the second break himself.〔BEA final report, section 2.1.1.3.1 "Choice of time period"〕 At 01:55 UTC, he woke the second pilot and said: "... he's going to take my place". After having attended the briefing between the two co-pilots, the captain left the cockpit to rest at 02:01:46 UTC. At 02:06 UTC, the pilot warned the cabin crew that they were about to enter an area of turbulence. It was probably two to three minutes after this that the airplane encountered icing conditions (the cockpit voice recorder recorded what sounded like hail or graupel on the outside of the airplane, and the engine anti-ice system came on) and ice crystals started to accumulate in the pitot tubes.〔BEA third interim report, p73〕 The pilots turned the aircraft slightly to the left and decreased its speed from Mach 0.82 to Mach 0.8 (the recommended "turbulence penetration speed").〔Palmer, pp. 4, 39〕 At 02:10:05 UTC the autopilot disengaged and the airplane transitioned from normal law to alternate law 2.〔Palmer, p.5〕 The engines' auto-thrust systems disengaged three seconds later. Without the auto-pilot, the aircraft started to roll to the right due to turbulence, and the pilot reacted by deflecting his side-stick to the left. One consequence of the change to alternate law was an increase in the aircraft's sensitivity to roll, and the pilot's input over-corrected for the initial upset. During the next 30 seconds, the aircraft rolled alternately left and right as the pilot adjusted to the altered handling characteristics of his aircraft.〔Palmer, p. 86〕 At the same time he made an abrupt nose-up input on the side-stick, an action that was unnecessary and excessive under the circumstances.〔BEA final report, section 2.1.2.3 "The excessive amplitude of these () inputs made them unsuitable and incompatible with the recommended aeroplane handling practices for high altitude flight."〕 The aircraft's stall warning sounded briefly twice due to the angle of attack tolerance being exceeded, and the aircraft's recorded airspeed dropped sharply from 274 knots to 52 knots. The aircraft's angle of attack increased, and the aircraft started to climb. By the time the pilot had control of the aircraft's roll, it was climbing at nearly 7,000 ft/min〔 (for comparison, typical normal rate of climb for modern airliners is only 2,000–3,000 ft/min at sea level, and much smaller at high altitude). At 02:10:34, after displaying incorrectly for half a minute, the left-side instruments recorded a sharp rise in airspeed to 223 knots, as did the Integrated Standby Instrument System (ISIS) 33 seconds later〔(BEA final report, appendix 2 (FDR chronology) ): 2 h 10 min 08: CAS changes from 274kt to 156kt. The CAS ISIS changes from 275 knots to 139 knots then goes back up to 223 knots. The Mach changes from 0.80 to 0.26. 2 h 10 min 09: CAS is 52kt. The CAS ISIS stabilises at 270 knots for four seconds. 2 h 10 min 34: CAS increases from 105kt to 223kt in two seconds. The CAS ISIS is 115 knots. 2 h 11 min 07: The CAS ISIS changes from 129kt to 183kt. The CAS is at 184kt. FDR graph parameters (in French): (– 2 h 10 min 04 to 2 h 10 min 26 ) (– 2 h 10 min 26 to 2 h 10 min 50 ) (– 2 h 10 min 50 to 2 h 11 min 47 )〕 (the right-side instruments are not recorded by the recorder). The icing event had lasted for just over a minute.〔Palmer, p. 7 "02:11:07 () The last of the pitot icing had cleared and all three airspeed indications were then displaying correctly"〕〔Palmer, p. 57 "The pitot icing lasted for about one minute and five seconds".〕〔BEA final report, p. 198 "The speed displayed on the left PFD was incorrect for 29 seconds, that of the speed on the ISIS for 54 seconds and the speed displayed on the right PFD for 61 seconds at most."〕 The pilot continued making nose-up inputs. The trimmable horizontal stabilizer (THS) moved from three to 13 degrees nose-up in about one minute, and remained in that latter position until the end of the flight. At 02:11:10 UTC, the aircraft had climbed to its maximum altitude of around 38,000 feet. There, its angle of attack was 16 degrees, and the engine thrust levers were in the fully forward Takeoff/Go-around detent (TOGA), and at 02:11:15 UTC the pitch attitude was slightly over 16 degrees and falling, but the angle of attack rapidly increased toward 30 degrees. A second consequence of the reconfiguration into alternate law was that "stall protection" no longer operated. Whereas in normal law, the airplane's flight management computers would have acted to prevent such a high angle of attack; in alternate law this did not happen. (Indeed, the switch into alternate law occurred precisely because the computers, denied reliable speed data, were no longer able to provide such protection – nor many of the other functions expected of normal law).〔Palmer, pp. 78–80〕 The wings lost lift and the aircraft stalled.〔 At 02:11:40 UTC, the captain re-entered the cockpit. The angle of attack had then reached 40 degrees, and the aircraft had descended to 35,000 feet with the engines running at almost 100% N1 (the rotational speed of the front intake fan, which delivers most of a turbofan engine's thrust). The stall warnings stopped, as all airspeed indications were now considered invalid by the aircraft's computer due to the high angle of attack.〔Palmer, p. 57. "This created a situation where the air was pushing into, in addition to flowing over, the static ports. () This dynamic accounts for the repeated falling of the airspeed to invalid values."〕 In other words, the aircraft was oriented nose-up but descending steeply. Roughly 20 seconds later, at 02:12 UTC, the pilot decreased the aircraft's pitch slightly, airspeed indications became valid and the stall warning sounded again and sounded intermittently for the remaining duration of the flight, but stopped when the pilot increased the aircraft's nose-up pitch. From there until the end of the flight, the angle of attack never dropped below 35 degrees. From the time the aircraft stalled until its impact with the ocean, the engines were primarily developing either 100 percent N1 or TOGA thrust, though they were briefly spooled down to about 50 percent N1 on two occasions. The engines always responded to commands and were developing in excess of 100 percent N1 when the flight ended. The flight data recordings stopped at 02:14:28 UTC, or three hours 45 minutes after takeoff. At that point, the aircraft's ground speed was 107 knots, and it was descending at 10,912 feet per minute (108 knots of vertical speed). Its pitch was 16.2 degrees (nose up), with a roll angle of 5.3 degrees left. During its descent, the aircraft had turned more than 180 degrees to the right to a compass heading of 270 degrees. The aircraft remained stalled during its entire 3 minute 30 second descent from 38,000 feet〔(【引用サイトリンク】url=http://www.bea.aero/en/enquetes/flight.af.447/info27may2011.en.php )〕 before it hit the ocean surface at a speed of 152 knots (280 km/h), comprising vertical and horizontal components of 108 and 107 knots respectively. The aircraft broke up on impact; everyone on board died, presumably instantaneously. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Air France Flight 447」の詳細全文を読む スポンサード リンク
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