Introduction
Two separate runway excursion events occurred at Melbourne Airport (MEL) during periods when runway length was reduced due to works in progress (WIP). The flight crews of both aircraft were aware of ongoing works but did not realize that the available runway length had been shortened at their departure times.
Events
Expecting a normal departure, each crew selected the pre-coded full-length runway 34 option when entering take-off performance data. This configuration incorporated reduced-thrust (FLEX or assumed temperature) settings that were incompatible with the significantly reduced runway length. Both performance tools offered a pre-coded reduced-length runway option (RWY 34 TMP/34-WIP) appropriate for the situation, but neither crew associated that option with a reduced-length departure.
Both aircraft performed as expected for the selected configuration. However, due to the shortened runway, they reached pre-determined rotation speed just before the temporary runway end and entered the runway end safety area (RESA) before lifting off. Afterward, individual crew members commented on the unusually close runway end lights and discussed the proximity of works, but this did not prompt reflection that they had forgotten to account for the shortened runway.
Contributing Factor
The flight crews of both aircraft did not recognize that reduced runway length operations were in effect at the time of departure. They conducted reduced-thrust take-offs based on the normal full runway length, resulting in each aircraft taking off beyond the end of the shortened runway, in close proximity to active runway works. Had they correctly identified the reduced length, performance calculations indicated sufficient runway for a safe take-off, even with a rejected take-off.
Communication and Information Systems
The incident analysis examined risk controls in place during the reduced runway length works, particularly communication of essential aerodrome information to flight crews. These included notices to airmen (NOTAMs), automatic terminal information service (ATIS), air traffic control (ATC) communications, internal pilot communications from operators and dispatchers, and aerodrome visual aids.
Notices to Airmen (NOTAMs)
NOTAMs are the primary mechanism for timely communication of essential aerodrome information. Every crew member had received a relevant 'REDUCED RUNWAY LENGTH' NOTAM in their flight briefing packs. However, both occurrence crews overlooked the applicable NOTAM during their reviews. Missing or misunderstood NOTAM information has been a factor in numerous previous occurrences. The NOTAMs available exhibited limitations: those of operational significance, such as reduced-length runway information, were not highlighted or prioritized above less safety-critical items, making them more likely to be overlooked.
Despite these concerns, no other overrun occurrences were reported during the displaced threshold works periods, suggesting that up to 30 departing flight crews each night correctly identified the hazard and used the appropriate runway length. Many of those were Australian pilots familiar with the airport, but foreign crews with minimal familiarity also operated without incident. The number of Melbourne Airport and runway NOTAMs was not excessive, and the subject of the relevant NOTAM was written clearly.