Air France Flight 296

Air France Flight 296 was a chartered flight of a new fly-by-wire Airbus A320-111 operated by Air France. On June 26, 1988, it was flying over Mulhouse-Habsheim Airport (ICAO code LFGB) as part of an air show. The low-speed fly-by was supposed to take place with landing gear down at an altitude of 100 feet (30 m). Instead, the plane slowly descended to 30 feet and crashed into the tops of trees beyond the runway. Three passengers died. This was the first crash of an Airbus A320. The cause of the accident is disputed, as many irregularities were later revealed by the accident investigation.

Official report
The official report states the causes of the accident were:


 * Very low flyover height, lower than surrounding obstacles.
 * Very low speed, slowing down to reach maximum possible angle of attack.
 * Engines at minimum idle flight power.
 * Late application of go-around power.

This combination led to the impact of the aircraft with the trees.

The Commission assumed that if the descent below 100 feet was not deliberate, it may have resulted from failure to take proper account of the visual and aural information intended to give the height of the aircraft.

A320 operation anomalies
Third-party investigations into the crash dispute the official findings. Captain Michel Asseline asserted that the altimeter read 30m (100'). However, while the pilots were trained in metric, this particular plane was in Imperial units. Air France didn't inform the crew of this critical change (yet the crew voices are recorded on black boxes, and they use imperial units).

Captain Asseline also reported that the engines didn't respond to his throttle input as he attempted to increase power and the elevators pushed the nose down.

Indeed during a re-creation of the flight at the Airbus facility at Toulouse, it was established that in the configuration the crash aircraft was in i.e. nose high, low speed, low engine power; the fly-by wire system did push the elevators down to keep to nose down to prevent the onset of a stall.

In the month prior to the accident, Airbus had posted two Operational Engineering Bulletins (OEBs) indicating possibilities of anomalous behavior in the A320 aircraft. These bulletins were received by Air France, but were not sent out to pilots until after the accident:

OEB 19/1: Engine Acceleration Deficiency at Low Altitude
This OEB noted that the engines may not respond immediately to throttle input at low altitude.

OEB 06/2: Baro-Setting Cross Check
This OEB stated that the barometric altitude indication on the A320 did not always function properly.

Captain Michel Asseline used those bulletins to assert that these 2 malfunctions happened and caused both the lack of power when the throttle was increased, and the inability of the crew to recognize the sharp sink rate as the plane passed 100 feet into the trees.

In fact none of those bulletins apply to the case. Moreover there is much evidence that engine power increased correctly and the airplane gave correct altitude.

First of all Captain Asseline was confident that there had been a malfunction in the engines and he was eager to cooperate with investigators.

Indeed the engines did not give strong power in 1 or 2 seconds as usual. This comes from the a pilot error of setting the engines at minimum idle flight. In this case specifications state that engines may take 5s to increase from complete idle to good power (80% of continuous max). The effect of the lack of power was increased with the slowing down and the extremely low speed, such that the tail was lower than the undercarriage. It can be pointed out that those conditions never happen during an actual landing and why pilots may have been confused by the airplane's poor reactions.

On the other hand the power of engines has been recorded on black boxes, and was subsequently proven to be correct. The engine sound had been recorded on the Cockpit Voice Recorder and amateur videos, and frequency analysis indicates the same increasing power.

Stating that the engine power had been carelessly set too low and go around too late, the investigators also focused on the incorrect altitude on the flight plan.

Regulations state that the airplane should stay at least 170 feet above the ground. For the special occasion of this show, the flight plan authorized a lower flight of 100 ft. The clear violation of this altitude was a big concern for pilots during coming trial, not ignoring that it was a major cause of crash. Thus Captain Asseline made all possible objections against this violation.
 * Firstly he stated that he respected the 100 ft. altitude. Yet the videos show that altitude had sunk to 30 ft and data recorders indicated the same.
 * He stated that the indication in cockpit was wrong, even if indications on data recorder were correct. Yet the Radio Altimeter announced height warnings and alarms in cockpit at 200 ft, 100 ft, then 50 ft, 40 ft, 30 ft... These warnings were recorded on the black boxes.
 * He stated that he did not hear these height warnings, because he wore a headset. Thus he may not have heard these warnings (and thus any other warning or alarm as they sound in cockpit and not always in the headset).
 * In further criticism of the investigation, Captain Asseline asserts that black boxes had been tampered with.
 * The flight data recorder and the cockpit voice recorder are 4 seconds out of synchronization during the last part of the recording.
 * To go further, he tried to have the black boxes regarded as irrelevant during his trial. Indeed they were taken out of airplane by French aeronautics authorities (DGAC) and Airbus, the manufacturer of the airplane is also French. The criminal investigators retrieved the black boxes and sealed them 10 days after DGAC had removed them from the crashed aircraft. Moreover he had a Swiss professor to demonstrate that the black boxes on trial were not the one out of the crash. It was demonstrated thanks to a rough photo (150 ft away) of the boxes carried away of the crash.
 * Coming back to basic piloting, regulations state it is mandatory for nearly all landings that pilots closing in on the ground have to take account of visual indications and must not refer to instruments. Captain Asseline asserts that he focused on altimeter before reaching 30 ft, and then his first officer reacted.

Captain Asseline made numerous interviews on media to advocate his case with these arguments and others. His allegations were often repeated.

Outcome
The accident and resulting fire killed 3 of the 130 passengers. Of those three, one was an adult and the other two were young children. It is believed that the adult, a female, had attempted to rescue a trapped 7 year old girl. During the evacuation, people had pushed on the back of the girl's seat, and the seat folded over on the girl who became trapped by her own seat belt. The woman had attempted to free the young girl from her seat, and both died of smoke inhalation. The second child, a male, was found impaled through the chest by a piece of wreckage.

Captain Asseline, First Officer Mazière, two Air France officials and the president of the flying club sponsoring the air show were all charged with involuntary manslaughter. All 5 were found guilty. Captain Asseline was initially sentenced to 6 months in prison along with 12 months of probation. The others were sentenced to probation. During the appeal process, Captain Asseline's sentence was increased to 10 months of imprisonment along with 10 months of probation. Asseline walked free from the court and said he would appeal to France's Supreme Court, the Cour de Cassation. According to French law, Asseline was required to submit himself to the prison system before his case could be taken up by the Supreme Court.

Dramatization
On 8 March 2010, an episode of the Mayday (Air Crash Investigation, Air Emergency) TV series featuring this accident was broadcast. The episode is entitled "Pilot vs. Plane".