Image copyright AFP Image caption In most cases of suspected airline pilot suicide, one pilot has managed to gain sole power over the controls and instigate a crash

A report by French investigators into the Germanwings plane crash in the French Alps in March says co-pilot Andreas Lubitz may have practised for a rapid descent on a previous flight. It also highlights six other accidents since 1980 that were possibly "caused by intentional manoeuvres by one of the flight crew members".

1) Namibia, 29 November 2013, 33 died

The aeroplane was at cruise flight level when the co-pilot left the cockpit to go to the toilet, leaving the captain alone in the cockpit. "On three occasions," the report says, "different altitudes were selected to order a descent to the ground with autopilot." The Cockpit Voice Recorder (CVR) showed several aural warnings, as well as "noises of repeated knocking and calls, corresponding to attempts to get into in the cockpit".

2) North Atlantic Ocean, 31 October 1999, 217 died

The cruising aircraft - flying from New York City to Egypt - had a flight crew comprising a captain, a duty co-pilot and a relief co-pilot. When the plane was crossing the ocean the duty co-pilot left the cockpit, followed eight minutes later by the captain. The relief co-pilot then disengaged the auto-pilot - and "nose-down inputs were recorded on the Flight Deck Recorder (FDR)". The aeroplane then rapidly descended after its engines were shut down. The captain returned to the cockpit and tried to take back control of the aeroplane, repeatedly asking the co-pilot for help "but [he] continued to command the elevator to pitch nose down". The aeroplane eventually "collided with the surface of the ocean", the report says. "The reasons that led the co-pilot to take these actions could not be determined."

3) Botswana, 11 January 1999, one died

The pilot, the only person on board, "deliberately flew the aeroplane into the ground by crashing at Gaborone airport". His licence had been revoked.

4) Indonesia, 19 December 1997, 104 died

While the aircraft was cruising at 10,000m (35,000ft) the flight recorders stopped recording "one after the other". The aeroplane suddenly started to come down. No Mayday message was transmitted before or during the descent. The aircraft crashed into a river. "The safety investigation was not able to identify any technical problem that would make it possible to explain the accident," the report says.

5) Morocco, 21 August 1994, 44 died

The captain disengaged the autopilot and deliberately directed the aircraft towards the ground. "The co-pilot was in the cockpit but was not able to counter the captain's actions."

6) Japan, 9 February 1982, 24 died

After disengaging the autopilot on the final approach at a height of 49m (164ft), the pilot pushed the control column forward and set the thrust levers on idle. He then moved the thrust levers of engines two and three to the reverse idle position. As the aircraft descended, the co-pilot tried to pull on the control column, but he was unable to raise the nose of the plane because the captain "was pushing forward on the control column with both hands". The aircraft crashed into the sea 510m short of the runway. An investigation showed that the actions of the pilot, who was among those who survived the crash, resulted from schizophrenia.