What happened
On 5 October 2020, a Hawker 850XP, registration HS-WTH, operated by Ratchthani Leasing Public Company Limited, was performing a flight from Don Mueang International Airport to Pattani Airport. The aircraft was carrying two pilots, one crew member, and four passengers.
As the aircraft approached runway 26 at Pattani Airport, the pilot disconnected the autopilot and configured the aircraft for landing with flap 45. Upon touchdown, the aircraft rolled for approximately 329 meters before veering to the right side of the runway centerline. The pilot attempted to correct the deviation by applying full left rudder, but the aircraft failed to respond and moved onto the runway safety area strip. During this excursion, the right main landing gear collided with a manhole, causing the right main tyre to burst. After traveling approximately 370 meters on the grass, the pilot regained control and steered the aircraft back onto the runway, taxiing for another 13 and a half meters before coming to a complete stop. There were no fatalities or injuries among the seven people on board.
The aircraft sustained substantial damage, including cracks and tears to the right main landing gear tyres, a damaged wheel hub, deformed torsion links, and a broken electrical cable and hydraulic hose clamp. Additionally, fuel leaked from the fuel tank manhole, and a runway edge light was broken.
The investigation
The investigation established that the aircraft belonged to Category C according to ICAO standards due to its landing speed, whereas Pattani Airport is only rated for Category A and B aircraft. While the pilots had calculated that the required landing distance of approximately 1,276 meters would fit within the 1,400-meter runway, they failed to recognize the airport's category restrictions.
Analysis of the Cockpit Voice Recorder (CVR) revealed that the pilot-in-command commanded "cut" regarding engine power while the aircraft was still 100 feet above the ground. This premature reduction in power caused the aircraft to sink into the runway surface more violently than intended, leading to a loss of lift and the subsequent loss of directional control.
Findings
- The pilots did not thoroughly review the Pattani Airport landing charts, leaving them unaware that the airport was restricted to Category A and B aircraft.
- The pilot's decision to reduce engine power prematurely (at 100 feet) caused the aircraft to hit the runway surface with excessive force, contributing to the loss of control.
- The collision with a manhole on the runway safety area strip caused significant damage to the right main landing gear and the destruction of a runway edge light.