SA 02: Robust procedures (before take-off)
In the course of the safety investigation concerning the serious incident involving the A320-214 Airbus aircraft, registration HB-IOP on 6 October 2014 at EuroAirport Basel Mulhouse Freiburg (LFSB), the Swiss Transportation Safety Investigation Board (STSB) identified a safety deficit and issued safety advice N° 2 in its final report no. 2256.
Target group(s)
Operator
Safety advice
The operator should optimise its procedures so that they exhibit high resilience. For example, applying a method of working in accordance with the closed loop principle can ensure that any errors or forgotten steps in the procedure can be quickly detected and rectified, especially in the case of reacting to a new situation. This should also include consideration of how much communication is appropriate within a multi-crew. On the one hand, the exchange of information should not be so great as to cause oversaturation or incorrect priorities to be set. On the other hand, situations where errors remain undetected due to insufficient communication or essential information is not made known to all crew members should be avoided.
Safety deficit
On 6 October 2014, the crew prepared the Airbus A320-214 aircraft, registration HB-IOP, for the flight with the flight plan call sign BHP 2532 from Basel (LFBS) to Djerba (DTTJ), Tunisia. Runway 15 was in use. The crew calculated the engine power for the entire available runway length of 3900 m and entered this data into the flight management and guidance system (FMGS) in the primary flight plan. The calculated speeds V1, VR and V2 were 157 kt. The crew entered the data for a take-off on runway 33 from the taxiway Delta intersection in the secondary flight plan. Before starting the engines the commander calculated the data for a takeoff on runway 15 from the taxiway Golf intersection on his electronic flight bag (EFB), which resulted in speeds of 136 kt and 138 kt respectively for V1, VR, and V2. The copilot calculated the data for a take-off on runway 15 from the taxiway Hotel intersection on his EFB.
While taxiing, the crew decided at short notice to save time by taking off from the taxiway Golf intersection, which offered an available runway length of 2370 m. Without stopping after lining up, they took off with an engine power which had been calculated for the entire length of the runway. This engine power did not meet the requirements for allowing the take-off to be continued or rejected within the remaining runway length in the event of engine failure at decision speed.
During the final stages of the take-off roll, the commander noticed that the engine power was too low, increased it to the maximum possible and at a speed of 150 kt began to lift off the aircraft by means of rotation. The subsequent climb and cruise were uneventful.
The investigation revealed that the operator's procedures stipulate that essential items such as confirming the take-off runway and checking the data entered into the FMGS are performed in silence by both pilots. This meant that neither pilot noticed that incorrect engine power and speeds had been entered for the takeoff.
As a result of a similar incident a year earlier, the aviation operator had introduced a „Before takeoff” caution box. This includes six checklist items for both pilots and is intended to prevent take-offs with incorrect take-off data. The crew was unaware of this caution box.