Blu Line flight BLE914P was a positioning flight from Paris Charles de Gaulle to Kuwait.
The co-pilot was the PF.
During the flight preparations, the PF input the information into the PMS: when inputting the aircraft weight, he mistakenly entered the aircraft’s zero fuel weight (ZFW) instead of its gross weight (GWT).
A “CHECK GWT” error message was displayed, and he entered a weight value again.
The PNF did not check the information that had been entered in the course of the pre-flight procedures and the various steps in preparation for take-off. mode was displayed on the FMA.
At 15.12, while the aircraft was levelling out at FL 260, the crew advised the Reims controller that they wished to climb to FL 370. Around one minute later, they were authorised to climb to FL 370.
At 15.14.37, as the aircraft climbed to FL 300 at a Mach speed of 0.77, the controller asked the crew whether it could reach FL 370 within four minutes, in anticipation of a crossing aircraft (see path tracks in Annex 1). Having consulted the performances in the PMS, which indicated a minimum Mach speed of 0.59, i.e. 187 knots, the crew replied that it was indeed able to comply. The PF selected a climb speed of Mach 0.65 in order to maintain a margin of safety in relation to the maximum capabilities of the aircraft.
At 15.18.09, while the aircraft was at around 2,700 ft from FL 370, the controller asked the crew to turn 20° to the left. He asked the crew of the other aircraft to do the same.
At 15.18.15, the Mach number started to decrease, reaching 0.65 Mach two minutes and ten seconds later.
At 15.19.13 the aircraft came out of the turn, and the calculated angle of attack was 3° (see Annex 2), which started to increase. The aircraft levelled off at FL 370 at 15.19.30. The Mach number was 0.67.
At 15.20.42, the angle of attack peaked at 5.2°. The Mach number was 0.64. The ATHR mode displayed on the FMA changed to MACH ATL
The crew reported that they felt buffeting and they thought that the aircraft was behind the power/speed curve. The aircraft was close to stalling speed.
At 15.20.44, the pilot manually disconnected the autopilot and began a descent, banking to the left. He informed the controller that he was descending to FL 330. The angle of attack decreased to 2.5°, then increased again, indicating that the thrust required to maintain Mach 0.65 was greater than maximum thrust.
The co-pilot of Blu Line flight BLE914P mistakenly input into the PMS the ZFW value of 86,520 lbs instead of the GWT value of 129,673 lbs. Since the value input was lower than 88,000 lbs, the “CHECK GWT” error message appeared.
The co-pilot stated that he then re-entered the weight value and the error message disappeared. He does not remember what value was entered. The pilot -in-command did not cross-check the weights entered.
At 15.21.03, the angle of attack was 6.1°
During the descent, the speed increased, which caused the buffeting to stop.
At 15.22.52, the crew interrupted the descent to FL 350 at Mach 0.73.
At 15.23.06, the autopilot was re-engaged. The aircraft accelerated, levelling off.
This mode indicates that the current Mach number is lower than the Mach number set and that the auto-throttle is currently demanding maximum thrust, displayed on the TRP. The pilot controlled the descent in order to avoid an aircraft operated by the airline Régional.
The crew stated that they had only noticed that the speed was unusually low.
The modes recorded are MACH and ALT HOLD.
The flight continued without further incident.
The incident, involving a near stall, was brought about by an error inputting the weight into the PMS.
Corrective action :
Following notification of the incident, the BEA sent the airline their study
The operator issued internal recommendations concerning:
- the verification in the assessment of competencies of knowledge of the magnitude of operational values;
- the introduction into a CRM module of the specific consequences of charter flights;
- the introduction into a CRM module of the importance of briefings and cross-checks;
- a reminder of the need to fill the card out again if the actual weight is more than 3 tons greater than the expected weight entered during flight the preparations;
- the changes to the procedures for improving the identification of cross-checks.