Thomson Airways Flight 1526

The outside air temperature was , but the operating crew entered incorrect figures (variously and ) for the airport outside air temperature, into the flight management computer, resulting in miscalculation of the required N, the engine fan speed (low-pressure compressor speed) required on the take-off run. (Both incorrect figures appeared as OATs on the flight plan: -47 °C at the first waypoint after top-of-climb, -52 °C at top-of-climb. == Aircraft ==

The incident aircraft was a Boeing 737-86J(WL) serial number 38124, registration C-FWGH. The aircraft was delivered to Air Berlin in 2011 as registration D-ABMC. The aircraft entered Sunwing Airlines fleet in 2017 following the bankruptcy of Air Berlin. During the time of the incident Thomson Airways had leased the aircraft for the summer season from 29 April until 31 October 2017. == Analysis ==

Usage of inaccurate takeoff data can be fatal, as it can lead to runway overruns and possibly collisions with obstructions, as happened in a 2004 accident at Halifax Airport in which seven people died. Neither the installed flight management computer software nor the Electronic flight bags (EFBs) in use helped in detecting the data input error. A recent software release had not yet been installed, and the software omitted the cross-check of the pilot input data against the outside air temperature actually measured. The pilot became aware of the aircraft's underperformance late in the take-off run 1 - but of course V1 was delayed, occurring further along the runway, by the low engine thrust. The Pilot Flying (the commander) judged (at 120-130kt, he said on interview) tht it was already too late to abort safely. - Squisherda, Oct-2019 "V1 is the critical engine failure speed or takeoff decision speed. It is the speed at which the pilot is to continue the takeoff in the event of an engine failure or other serious emergency. At speeds less than V1, it is considered safer to stop the aircraft within the accelerate-stop distance [unless of course an anomalously slow acceleration has meant tht more - maybe much more - runway than anticipated has already been used by the time V1 is reached. V1, as calculated, then becomes irrelevant. In this case the Pilot Flying reckoned he was already out of stopping-space 30kt before the calculated V1]. It is also the minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface." -->but did not intervene effectively. The Report explored various human-factors aspects of the incident, concluding that the pilots could not reasonably have been expected to respond more quickly to the developing situation, either before or after becoming airborne. It reviews and lists recent incidents of aircraft underperformance at take-off, reviews industry efforts to provide automatic warning in such situations, and calls for closer regulatory attention to pilots' portable computers ('electronic flight bags'). • Takeoff Performance Monitoring System (TOPMS) or Takeoff Acceleration Monitoring System (TAMS). A 2019 research paper explores the cause of this serious incident, caused by erroneous data entry. The paper "summarises a basic takeoff acceleration monitoring system and the effect this would have had on the July 2017 event". == References ==