What happened
On 7 January 2005, an Avro 146-RJ100, registration G-CFAA, was performing a scheduled passenger flight to London City Airport. The flight crew, operating a 53-passenger service, encountered significant wind activity during the approach to Runway 28. The weather conditions were characterized by winds from 230 degrees at 25 knots, gusting to 33 knots.
During the final stages of the approach, the commander elected not to add a speed increment for the gusts, a decision influenced by recent experiences with windshear and reports from a preceding aircraft. As the aircraft descended, the crew applied thrust increases to manage the approach. However, during the flare maneuver, the aircraft's pitch increased to 6.6 degrees, causing the tail to contact the runway surface.
Following the landing, a routine inspection by an engineer revealed damage to the Ground Strike Indicator (GSI) located under the aircraft's tail. The damage was limited to the scraping and crushing of the aluminum strip, and no structural damage to the aircraft was found.
The investigation
The AAIB investigation examined flight recorder data, including the Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR). The FDR analysis revealed that at approximately 85 feet above the ground, an increase in engine thrust coincided with a significant drop in airspeed, which fell by 16 knots over a three-second period. This deceleration occurred while the ground speed only saw a marginal increase.
Investigators also examined the runway surface, where they identified paint deposits and scrape marks approximately 50 cm to the right of the centerline. These marks were consistent with the paint from the underside of the aircraft's tail area.
Findings
- The tail strike was caused by an encounter with significant negative windshear immediately prior to touchdown.
- The aircraft's airspeed dropped to 10 knots below the reference speed (Vref) by 35 feet, making a standard touchdown difficult.
- The commander's decision to maintain a lower approach speed, while intended to avoid high-energy impacts, left insufficient margin to compensate for the sudden loss of airspeed caused by the windshear.
- The damage was confined to the Ground Strike Indicator and did not penetrate the aircraft structure.