History
On 28 February 2020, a Boeing 737-8B6 (registration CN-RGJ) operated a commercial passenger flight from Casablanca to London Gatwick. The outbound flight was uneventful. During the turnaround at Gatwick, the crew prepared for the return sector. The co-pilot was the pilot flying. Runway 26L was in use with a light southerly wind and rain, broken cloud at 900 ft, and temperature 6°C. The crew planned a departure from intersection A using flap 1 and an assumed temperature of 55°C. Calculated takeoff speeds were V1 144 kt, VR 152 kt, and V2 155 kt. The commander reported that these speeds were loaded into the Flight Management Computer (FMC) while on stand.
The aircraft entered the runway at intersection A and was cleared for takeoff. At 80 kt, the commander confirmed normal airspeed indications. The crew expected to hear the automatic "V1" call, but it did not occur. The commander noticed that V speed bugs were not displayed on the Primary Flight Display (PFD). He felt the aircraft was slow and allowed it to accelerate while evaluating the situation. As the end of the runway approached, he instructed the co-pilot to initiate a smooth rotation. The aircraft took off and the rest of the flight was uneventful. No caution or warning messages were observed.
Recorded Information
The Quick Access Recorder (QAR) data showed that the nosewheel lifted off at 189 kt, approximately 120 m before the end of the runway, at 196 kt and 13 seconds after the planned rotation speed. The QAR also recorded that the V speeds were blank throughout the taxi and takeoff, while the assumed temperature (55°C) and MCP selected speed (155 kt) were present. The V speeds were recorded normally on preceding and subsequent flights.
Aircraft Information
The Boeing 737's takeoff V speeds are normally entered into the FMC during preflight. If speeds are missing, a "no vspd" message appears on the PFD. The aircraft manufacturer stated it was not aware of any situation where V speeds could be deleted without these warnings appearing. The Boeing 737 Flight Crew Training Manual (FCTM) provides guidance for managing missing speed bugs, including using the displayed V2 speed on the MCP as a reference.
Analysis
It is likely that the automatic call and speed bugs were absent because the V speeds were not present in the FMC. The QAR data suggest that the speeds were not loaded when the engines were started. It is possible that the flight crew did not enter them, or that they were inadvertently deleted afterwards, but the crew did not recall seeing the alerting messages. The commander believed the aircraft was slow and prioritized having more speed, resulting in a rotation speed significantly above the correct VR.
Conclusion
During the takeoff roll, the V1 automatic call did not occur and the takeoff speeds were not displayed on the PFD. This led to a late rotation, 37 kt above the correct speed and with only 120 m of runway remaining.