The Germanwings co-pilot suspected of deliberately crashing a plane in the French Alps in March, killing all 150 people on board, practised a descent in the last 50 minutes of a previous flight on the same day.
The preliminary report by the French Civil Aviation Safety Investigation Authority (BEA) said Andreas Lubitz changed the altitude several times, even to 100 feet (30.48 meters) while cruising from Duesseldorf to Barcelona on the outbound flight when the captain went out of the cockpit.
The abnormal deliberate altitude changes continued until “noises like those of the unlocking of the cockpit door then its opening was recorded and corresponded to the Captain’s return to the cockpit”.
When a similar situation happened on the return flight from Barcelona to Duesseldorf later, he locked the captain out of the cockpit and crashed the plane.
He “intentionally modified the autopilot instructions to order the aeroplane to descend until it collided with the terrain. He did not open the cockpit door during the descent, despite requests for access made via the keypad, the cabin interphone and knocks on the door,” reads the report.
Lubitz is known to have from severe depression and a computer found in his home showed he had researched had researched suicide methods and the security of cockpit doors online.
Extract from the Report:
On the previous flight, the following facts can be noted:
at 7 h 19 min 59, noises like those of the cockpit door opening then closing were recorded and corresponded to when the Captain left the cockpit; the aeroplane was then at cruise speed at flight level FL370 (37,000 ft);
at 7 h 20 min 29, the flight was transferred to the Bordeaux en-route control centre and the crew was instructed to descend to flight level FL350 (35,000 ft), an instruction read back by the co-pilot;
at 7 h 20 min 32, the aircraft was put into a descent to flight level FL350 , selected a few seconds earlier
at 7 h 20 min 50, the selected altitude decreased to 100 ft for three seconds and then increased to the maximum value of 49,000 ft and stabilized again at 35,000 ft;
at 7 h 21 min 10, the Bordeaux control centre gave the crew the instruction to continue the descent to flight level FL210;
at 7 h 21 min 16, the selected altitude was 21,000 ft;
from 7 h 22 min 27, the selected altitude was 100 feet most of the time and changed several times until it stabilized at 25,000 ft at 7 h 24 min 13;
at 7 h 24 min 15, the buzzer to request access to the cockpit was recorded;
at 7 h 24 min 29 noises like those of the unlocking of the cockpit door then its opening was recorded and corresponded to the Captain’s return to the cockpit.
The full English version of the Preliminary Report is available here.