What happened
On July 15, 2017, at 22:41 JST, a Boeing 747-8F, registered N852GT, operated by Polar Air Cargo Worldwide, Inc., experienced a serious incident at Narita International Airport. While performing a scheduled flight to Shanghai Pudong International Airport, the aircraft began its takeoff roll on runway 16L. However, the aircraft failed to achieve rotation until it reached the vicinity of the end of the departure runway, creating a situation equivalent to a runway overrun. There were no injuries to the crew, and the aircraft sustained no damage.
The investigation
The Japan Transport Safety Board (JTSB) investigated the event, examining flight data recorder (FDR) and quick access recorder (QAR) data, cockpit voice recorder (CVR) transcripts, and interviews with the flight crew. The investigation focused on the takeoff performance parameters and the crew's preparation for the departure. Investigators analyzed the Flight Management Computer (FMC) settings and the engine indication values (N1) during the takeoff roll. The investigation also looked into the company's procedures for communicating runway assignments and the crew's verification processes during runway changes.
Findings
At the time of the incident, the crew had expected to use runway 16R, which offered a shorter taxi route from their parking position. Although they were assigned runway 16L, the captain updated the FMC with the new runway information but failed to correctly adjust the takeoff thrust settings. Specifically, while the assumed temperature was updated, the rated takeoff thrust remained set to a de-rated value.
During the takeoff roll, the actual N1 engine values reached only 89.1%, significantly lower than the 97.2% required for the aircraft's weight and the specific runway conditions. The crew did not recognize this discrepancy as abnormal, partly because the N1 values were similar to what they had expected for a takeoff from runway 16R. The heavy workload of navigating a complex taxi route to runway 16L likely distracted the crew from verifying the takeoff performance data. Consequently, the insufficient takeoff thrust resulted in an extended takeoff roll that ended just 340 feet before the runway terminus.
Safety action
Following the incident, Polar Air Cargo Worldwide, Inc. implemented several safety measures, including:
- Conducting retraining for flight crews on FMC performance data input and verification.
- Establishing a specific checklist for runway changes to ensure strict adherence to standard operating procedures.
- Revising airport information provided to crews to clearly communicate runway assignment procedures at Narita.
- Integrating the findings of this incident into recurrent training programs based on Threat and Error Management (TEM) principles.