What happened
On 1 July 2000, a Fokker F27 Mark 500, registration G-JEAP, was performing a cargo flight from Belfast to Coventry. During the approach to Runway 23 at Coventry Airport, the aircraft was flying significantly faster and higher than the target parameters. The crew was aware of the high airspeed and the deviation from the glidepath, but the landing was continued.
The aircraft touched down approximately 300 metres beyond the intended touchdown point at a speed of 114 kt, which was 19 kt above the target Vref. Following touchdown, the aircraft failed to decelerate effectively. Although the crew believed they had selected ground fine pitch (GFP) for the propellers, evidence suggests this selection did not occur at the appropriate time in the landing roll. Consequently, the aircraft lacked the necessary aerodynamic drag to stop within the remaining runway length.
As the aircraft reached the end of the paved surface, it veered left and struck a concrete plinth supporting an ILS monitor aerial. The impact caused the nose landing gear to collapse. The aircraft then slid across the grass, striking the airfield perimeter fence before coming to a halt near a minor road. There were no injuries to the two crew members, but the aircraft sustained significant damage to the nose section, propellers, and engine nacelles.
The investigation
Investigators from the AAIB examined the wreckage, flight data recorder (FDR), and cockpit voice recorder (CVR). The investigation focused on the discrepancy between the crew's belief regarding propeller pitch selection and the actual performance of the aircraft. Analysis of the CVR and FDR confirmed that the propellers did not enter the ground fine pitch range for the majority of the landing roll.
Engineers also reviewed the aircraft's performance manuals. It was discovered that the target threshold speed provided in the operator's manual (Vthr) was 8 kt higher than the certified threshold speed (Vat). Furthermore, the investigation looked into the crew's use of the 26.5° flap setting, which was a company policy but resulted in reduced deceleration compared to higher flap settings.
Findings
- The landing was continued despite the aircraft being above the calculated threshold speed and touching down late.
- Ground fine pitch was not selected at the correct stage of the landing roll, depriving the aircraft of essential aerodynamic braking.
- The aircraft's landing speed was significantly higher than the target, contributing to a lack of weight on the main wheels and reduced braking effectiveness.
- Discrepancies in the aircraft manuals meant the crew was using a higher target threshold speed than certified.
- The flaps were not retracted after touchdown, which further impacted the landing distance.