Synopsis
On 3 March 2021, at 15:36 UTC, a KLM Boeing 737-800 (registration PH-BCD) operating flight KL1696 from Lisbon Airport (LPPT) to Amsterdam Airport (EHAM) experienced a serious incident during take-off from runway 21. The aircraft took off from intersection U5 with approximately 284 meters of runway remaining, crossing the threshold at a radio altitude between 45 and 70 feet. No injuries or aircraft damage were reported.
Factual Occurrence Description
The flight to Lisbon was uneventful, after which a new cabin crew replaced the previous one. The new crew informed the flight crew about passenger congestion at the terminal due to Covid test verification, confirmed by KLM's Station Manager, who estimated a 30-minute delay.
The flight crew began preparations for the return flight, including entering take-off data into the on-board LINTOP (Lido Integrated Takeoff Performance) tool. They selected the S1 intersection of runway 21, but the tool displayed a message stating "INTERSECTION DATA NOT AVAILABLE" because S1 is not a valid take-off point.
According to the operator's analysis, the crew then re-entered take-off data omitting the digit "1", entering intersection "S" instead. The system accepted PSN S as a valid take-off point, which on the operator's chart corresponds to intersection S4. After receiving the load sheet, the crew re-entered the LINTOP system because the take-off mass exceeded the gross mass used in the first calculation. The take-off point was not changed. The take-off speeds and assumed temperature entered in the FMS corresponded to a calculation for the full length of runway 21.
The aircraft subsequently taxied to runway 21 intersection U5, as instructed by ATC, and began take-off at 15:36 UTC. The main landing gear lifted off with approximately 284 meters of runway remaining, and the aircraft crossed the threshold at a radio altitude between 45 and 70 feet. The flight proceeded and landed at the destination airport without issues or recorded damage.
The crew, comprising a captain as pilot flying (PF) and a first officer as pilot monitoring (PM), did not notice any performance issues during the take-off roll. Both crew members stated that fatigue was not a factor. The captain and first officer had 21 and 12 rotations at Lisbon Airport, respectively. It could not be determined whether the boarding delay caused distractions affecting data input.
Safety Relevant Findings
Based on the available data, GPIAAF considered it appropriate to reiterate to Lisbon Airport operators and relevant national entities the risks involved in take-off operations on runway 21 from intersections with a TORA (Take-Off Run Available) shorter than planned. For air operators, GPIAAF underlined the industry's concern regarding take-off procedures, emphasizing that standard operating procedures should require flight crews to perform a check of take-off data and cross-check results with each other.
Event data was processed by the operator and analyzed by the flight safety team six weeks after the occurrence, having been flagged in a monthly flight monitoring report.