What happened
On June 9, 2015, a Boeing 737-3S3, registration PR-SDL, operated by Sideral Linhas Aéreas, was performing a cargo flight from Teresina to São Luís, Brazil. Approximately 15 nautical miles from the destination, the crew requested to cancel their IFR flight plan and proceed under visual flight rules (VFR).
During the approach to runway 06, the crew executed a right-hand base leg. As the aircraft performed the flare for landing, the right wingtip made contact with the runway surface. The impact caused light damage to the slats, the wingtip, the flap, and the outermost flap track fairing. The two crew members were uninjured.
The investigation
CENIPA investigators analyzed flight data from the Solid State Flight Data Recorder (SSFDR) and the Cockpit Voice Recorder (CVR). The investigation focused on the aircraft's flight parameters during the final stages of the approach.
Data revealed that at 300 feet above the aerodrome, the aircraft was in a turn with a descent rate exceeding 1,000 feet per minute and a bank angle of 9 degrees. The flight path lacked a defined straight-in final approach, characterizing an unstabilized approach. Furthermore, at the moment of touchdown, the aircraft's pitch angle was 4 degrees and the roll angle was 15 degrees. This roll angle exceeded the operational limits for a normal landing, which directly led to the wingtip strike.
Findings
- Unstabilized approach: The crew failed to establish a stabilized approach, characterized by the lack of a straight-in final and excessive descent rates.
- Improper flight control application: The crew used flight controls that resulted in a roll angle exceeding the manufacturer's normal landing limits.
- Erroneous decision-making: The crew incorrectly judged they had full control of the situation and failed to execute a missed approach (go-around) despite the unstable conditions and the influence of a crosswind.
- Operational procedures: The company's General Operations Manual allowed VFR approaches but lacked specific parameters or restrictions to ensure stabilized approaches.