What happened
During the final approach for runway 01, an aircraft encountered moderate to severe turbulence. The flightcrew performed pre-landing checks with the landing gear down and flaps in the 25-degree extended position. During the approach, the crew missed several radio transmissions, including a report from a preceding aircraft regarding a go-around and subsequent good braking action.
While Air Traffic Control relayed the report of good braking action to the crew, that report was based on an aircraft equipped with thrust reversers, whereas the subject aircraft was not. The pilot reported flying the final approach without full flaps at Vref plus 20 (139 knots) due to wind conditions, eventually slowing to 134 knots over the runway threshold. At the time, the asphalt runway, measuring 7,000 feet in length and 150 feet in width, was contaminated with thin slush.
The investigation
A review of takeoff and landing data (TOLD) retrieved from the cockpit showed that for a landing weight of 20,000 pounds with full flaps, a required distance of 4,240 feet was calculated based on a dry runway. However, calculations using an effect of slippery runway chart indicated that the equivalent scheduled landing distance available on the contaminated runway was approximately 3,200 feet.
Findings
- The pilot and copilot had not flown together prior to the incident.
- The copilot spoke broken English.
- Although the ATIS information reported thin slush on all surfaces, the captain did not inquire about runway conditions, and the copilot failed to relay the information.
- The crew missed critical radio communications due to turbulence.
- The reliance on braking action reports from an aircraft with thrust reversers was inappropriate for an aircraft without such equipment.