Aviation

An ‘Understandable’ Mix-Up

by rudy

First story

The very experienced crew of an ATR-72 takes off from Köln/Bonn airport on 27 April 2020 but instead of lining up with the middle of runway 06, they position the aircraft at the runway edge. During the take-off run, they notice various “blows to the aeroplane” caused by the runway edge lights hitting parts of the fuselage causing damage, the nose landing gear and the propellor blades. The aircraft travelled about 805 m (2,641 ft) and reached a groundspeed of 86kt before the takeoff was rejected and the aeroplane returned to the apron.

Generic image of an ATR-72

Second story

In the morning darkness, the pilots back-tracked the runway (i.e. they taxied on the runway in the opposite direction of take-off) to the end and made a 180° turn to line up for take-off. During the turn, the pilots heard a noise and initially thought that the cockpit door had opened, but the subsequently determined that the captain’s bag had fallen behind his seat. The captain completed the turn with the white lights in front of him. Both pilots were convinced they were correctly aligned with the runway centreline before they initiated the take-off. What made them believe they were on the right spot?

  • Runway edge lights and runway centreline lights are both white
  • The white runway edge marking at the turn pad strongly resembled the runway centreline markings
  • “in darkness, it is difficult to identify the precise dimensions of an aeroplane and its correct position, due to the distance and the lack of reference points.”
  • Ironically, the fair weather (+10km visibility, ceiling at 5000ft) may have caused the crew to less attentive with regards to aircraft position.
  • Due to the flat angle from the cockpit towards the respective lighting (runway edge and centreline), the different distances between the individual lamps of the corresponding chain of lights could barely or not at all be seen.
  • Due to construction works a backtrack procedure needed to be executed which necessitated a 180° turn.
  • The unusual width of turn pad including runway (lack of references)

With regards to safety nets:

  • The accuracy of the ground radar is insufficient to detect a misalignment (the aircraft symbol is as wide as the runway)
  • The tower air traffic controller’s workstation was oriented toward Runway 14L/32R, which served 90 per cent of traffic. To see an aeroplane at takeoff position 06, you have to turn around and stand up.
Taxi traces of the landing gears, which originate from the alignment with the runway edge lighting (BFU Report)

Source: BFU Investigation Report No. BFU20-0251-EX, FSF AeroSafety World (8 february 2021)