Boeing 747 Take-off Incident at Changi Airport Due to Weight Calculation Error

Casualties unknown • SG

A Boeing 747-300 struck runway marker boards during take-off at Singapore Changi Airport after the crew exceeded the weight limit for a shortened runway.

What happened

On 2 June 2007, a Boeing 747-300, registration HZ-AIT, was departing Singapore Changi Airport for Riyadh. Due to ongoing resurfacing work, the available take-off run on Runway 20C had been reduced to 2,500 meters. During the take-off roll, the aircraft struck runway end marker boards and light assemblies, causing significant damage to 11 of the 13 triangular boards and several concrete weights. While the crew and all 388 passengers remained uninjured, the aircraft's tires left rubber traces on the destroyed equipment. The incident came to light when air traffic controllers in Kuala Lumpur queried the crew regarding the nature of their departure.

The investigation

The investigation focused on how the aircraft exceeded the safe weight limit for the reduced runway length. Investigators examined the Module Table Take-off and Landing (MTTL) charts used by the crew, noting that the runway length specifications were located on a separate page from the primary data table. The inquiry also reviewed the airline's dispatch procedures and the airport operator's response to the incident, including the cleanup of debris before investigators could document the scene.

Findings

  • The First Officer used the wrong column in the MTTL chart, selecting data for a full-length runway rather than the reduced 2,500m runway.
  • The Pilot-in-Command did not cross-check the weight calculations performed by the First Officer.
  • The crew was unfamiliar with the specific format of the provided MTTL charts, as they had not been briefed on the recent change in document layout.
  • The runway length information was difficult to access because it was printed on the second page of the chart, away from the primary data table.
  • The airline's dispatch office failed to include the shortened runway information in the company's NOTAMs.
  • The airport operator cleared the debris from the site before the investigation could properly assess the spread of the wreckage.

Safety action

Following the investigation, the flight handling agent implemented a new checklist to ensure all necessary flight documents are verified during pre-flight briefings. The airport operator also updated its incident management protocols to ensure better evidence preservation and more rigorous classification of serious incidents.

Probable cause

The incident was caused by the flight crew's failure to correctly identify the appropriate take-off weight limit for the shortened runway, compounded by a lack of cross-checking procedures and an unfamiliar chart format that separated runway length data from the weight tables.

Frequently asked questions

What happened in the 2007-06-02 Boeing B777-200ER accident near SG?

A Boeing 747-300 struck runway marker boards during take-off at Singapore Changi Airport after the crew exceeded the weight limit for a shortened runway.

What aircraft was involved and where did it happen?

The accident on 2007-06-02 involved a Boeing B777-200ER, at SG.

What was the probable cause of the accident?

The incident was caused by the flight crew's failure to correctly identify the appropriate take-off weight limit for the shortened runway, compounded by a lack of cross-checking procedures and an unfamiliar chart format that separated runway length data from the weight tables.

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