What happened
On 13 February 1999, a Saab-Scania SF340A, registration G-GNTF, was performing a scheduled public transport flight at East Midlands Airport. The crew, consisting of a commander and a first officer, were operating the final sector of a four-sector day. During the approach to Runway 27, the aircraft was instructed to reduce speed due to a departing Boeing 737.
As the aircraft approached the threshold, the first officer disconnected the autopilot. The aircraft began to drift from the centerline and experienced a period of floating above the runway. The commander subsequently took control, but the aircraft landed heavily on the main gear and pitched forward. This impact caused the nose wheel to strike the runway surface. The pilot applied braking and taxied the aircraft to a stop on taxiway 'D'. There were no fatalities and no injuries among the 34 passengers or 3 crew members.
The investigation
Investigators examined the aircraft's flight data and cockpit voice recordings, which confirmed the sequence of events. Flight data revealed that the aircraft experienced pitch oscillations during the final stages of the approach, reaching a maximum pitch attitude of 6.7 degrees at a very low radio height before touching down with a peak normal acceleration of 2.47g.
Physical inspection of the landing gear revealed that the rims on both nose wheels had disintegrated upon impact, causing the wheels to wear down to the hubs. This process caused minor damage to a propeller blade and the forward fuselage. Analysis of the debris and runway marks indicated that the failure of the wheel rims was caused by a sudable overload during the heavy landing.
Findings
- The primary cause of the landing gear damage was the sudden mechanical overload of the nose wheel rims during a heavy touchdown.
- The aircraft experienced a period of floating and subsequent heavy impact following a loss of airspeed and pitch control.
- The commander noted that fatigue may have played a role, as he was on his third consecutive day of early starts to facilitate line training duties.
- The aircraft's nose wheel rims failed, leading to the disintegration of the wheels and subsequent damage to the fuselage and propeller.