Air France Flight 447

Information
Air France Flight 447 was a flight from Rio de Janeiro, Brazil, to Paris, France. On June 1, 2009, the plane stalled and didn't recover, eventually impacting the Atlantic Ocean.

Pilots
The captain, 58-year-old Marc Dubois had joined Air France (at the time, Air Inter) in February 1988 and had 10,988 flying hours, of which 6,258 were as captain, including 1,700 hours on the Airbus A330; he had carried out 16 rotations in the South American sector since arriving in the A330/A340 division in 2007.

The first officer, co-pilot in left seat, 37-year-old David Robert had joined Air France in July 1998 and had 6,547 flying hours, of which 4,479 hours were on the Airbus A330; he had carried out 39 rotations in the South American sector since arriving in the A330/A340 division in 2002. Robert had graduated from École Nationale de l'Aviation Civile (ENAC), one of the elite Grandes Écoles, and had transitioned from a pilot to a management job at the airline's operations center. He served as a pilot on this flight in order to maintain his flying credentials.

The first officer, co-pilot in right seat, 32-year-old Pierre-Cédric Bonin had joined Air France in October 2003 and had 2,936 flight hours, of which 807 hours were on the Airbus A330; he had carried out five rotations in the South American sector since arriving in the A330/A340 division in 2008. His wife, Isabelle, a physics teacher, was also on board.

Background
The aircraft departed from Rio de Janeiro–Galeão International Airport at 7:29 pm Brazilian standard time (10:29 pm UTC) and was scheduled to arrive at Paris-Charles de Gaulle Airport at 11:03 am (9:03 am UTC) the following day, with an estimated flight time of 10 hours and 34 minutes. Voice contact with this flight was lost around 1:35 am UTC, the last reported message being that they had passed waypoint INTOL. The flight left Brazilian Atlantic radar surveillance at 01:49 UTC, and entered a communication dead zone.

The Airbus A330 is designed to be flown by two pilots. However, the 13-hour "duty time" (flight duration, plus pre-flight preparation) required for the Rio-Paris route exceeds the 10 hours permitted before a pilot must take a break dictated by Air France's procedures. To comply with these procedures, Flight 447 was crewed by three pilots: a captain and two first officers. With three pilots on board, each could rest in the A330's rest cabin located behind the cockpit.

In accordance with common practice, captain Dubois had sent one of the co-pilots for the first rest period with the intention of taking the second break himself.[64] At 01:55 UTC, he woke first officer Robert and said that "he's going to take my place". After attending 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 (Bonin) warned the cabin crew that they were about to enter an area of turbulence. About two to three minutes later, the aircraft encountered icing conditions (the cockpit voice recorder (CVR) recorded what sounded like hail or graupel on the outside of the aircraft) and ice crystals started to accumulate in the pitot tubes, which measure airspeed.[65] Bonin turned the aircraft slightly to the left and decreased its speed from Mach 0.82 to Mach 0.8 (the recommended "turbulence penetration speed"). The engine anti-ice system was turned on.

At 2:10:05 am UTC the autopilot disengaged, most likely because of the blocked pitot tubes. The aircraft transitioned from normal law to alternate law 2. The engines' auto-thrust systems disengaged three seconds later. As the pilot flying, Bonin took over control of the aircraft, and said, "I have the controls." Without the auto-pilot, the aircraft started to roll to the right due to turbulence, and Bonin 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. During the next 30 seconds, the aircraft rolled alternately left and right as Bonin adjusted to the altered handling characteristics of the aircraft. At the same time he abruptly pulled back on his side-stick, raising the nose. This action has been described as unnecessary and excessive under the circumstances. The aircraft's stall alarm sounded briefly twice due to the angle of attack tolerance being exceeded, and the aircraft's recorded airspeed dropped sharply from 274 knots (507 km/h; 315 mph) to 52 knots (96 km/h; 60 mph). The aircraft's angle of attack increased, and the aircraft started to climb above its cruising level of FL350. By the time the pilot had control of the aircraft's roll, it was climbing at nearly 7,000 feet per minute (36 m/s; 130 km/h). The typical normal rate of climb for modern airliners is 2,000–3,000 feet per minute (10–15 m/s; 37–55 km/h) at sea level, and much smaller at high altitude and, also for comparison, a typical updraft speed for a severe storm is 120 km/h.

At 02:10:34 am UTC, after displaying incorrectly for half a minute, the left-side instruments recorded a sharp rise in airspeed to 223 knots (413 km/h; 257 mph), as did the Integrated Standby Instrument System (ISIS) 33 seconds later (the right-side instruments are not recorded by the recorder). The icing event had lasted for just over a minute. Bonin 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 position until the plane crashed.

At 02:11:10 am UTC, the aircraft had climbed to its maximum altitude of around 38,000 feet (12,000 m). There, its angle of attack was 16 degrees, and the engine thrust levers were in the fully forward Takeoff/Go-around detent (TOGA). As the aircraft began to descend, 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 aircraft'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). The wings lost lift and the aircraft started stalling.

Confused, Bonin exclaimed "I don't have control of the airplane any more now", and two seconds later, "I don't have control of the airplane at all!" First officer Robert responded to this by saying, "controls to the left", and took over control of the aircraft. Robert pushed his side-stick forward to lower the nose and recover from the stall; however, Bonin was still pulling his side-stick back. The inputs cancelled each other out and triggered an aural "dual input" warning.

At 02:11:40 am UTC, captain Dubois re-entered the cockpit after being summoned by first officer Robert. Noticing the various alarms going off, he asked the two crew members what they were doing. The angle of attack had then reached 40 degrees, and the aircraft had descended to 35,000 feet (11,000 m) 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. The aircraft had its nose above the horizon but was descending steeply.

Roughly 20 seconds later, at 02:12 am UTC, Bonin decreased the aircraft's pitch slightly, airspeed indications became valid, and the stall warning sounded again; it then 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. First officer Robert responded to Captain Dubois by saying: "We've lost all control of the airplane, we don’t understand anything, we’ve tried everything". Soon after this, Robert said to himself to "climb" four consecutive times. Bonin heard this and replied, "But I've been at maximum nose-up for a while!" When Captain Dubois heard this, he realized Bonin was causing the stall, and shouted, "No no no, don't climb! No no no!"

When First Officer Robert heard this, he told Bonin to give the control of the airplane to him. In response to this, Bonin would temporarily give the controls to Robert. Robert pushed his side stick forward to try to regain lift for the airplane to climb out of the stall. However, the aircraft was now too low to recover from the stall. Shortly thereafter, the Ground Proximity Warning System sounded an alarm, warning the crew about the aircraft's now imminent crash with the ocean. In response, Bonin (without informing his colleagues) pulled his side stick all the way back again. Robert said, "[Expletive] We're going to crash! This can't be true." Bonin replied with "But what's happening?" The last recording on the CVR was captain Dubois saying: "(ten) degrees pitch attitude."

The flight data recordings stopped at 02:14:28 UTC, or 3 hours and 45 minutes after takeoff. At that point, the aircraft's ground speed was 107 knots (198 km/h; 123 mph), and it was descending at 10,912 feet per minute (55.43 m/s) (108 knots (200 km/h; 124 mph) 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 and a half minute descent from 38,000 feet (12,000 m). The aircraft struck the ocean belly-first at a speed of 152 knots (282 km/h; 175 mph), comprising vertical and horizontal components of 108 knots (200 km/h; 124 mph) and 107 knots (198 km/h; 123 mph) respectively. All 228 passengers and crew on board died on impact from extreme trauma and the aircraft was destroyed.