What happened
On June 16, 2018, a commercial Boeing 737-800, registration EI-FHD, was performing a takeoff roll on Runway 01 at Keflavik Airport. During the acceleration phase, the flight crew felt unusual vibrations originating from the nose landing gear. Shortly after liftoff, the crew observed the antiskid inoperative light. As the aircraft climbed, the crew identified a significant loss of quantity in hydraulic system A, which eventually progressed to a total loss of pressure in the system.
Simultaneously, Air Traffic Control informed the crew that tire rubber and metal debris had been discovered on the runway. The crew evaluated the situation, noting the combination of a tire burst, hydraulic failure, and runway debris. Due to the degraded landing performance—including inoperative ground spoilers, reduced braking effectiveness, and the risk of a runway excursion on the wet Keflavik runways—the crew decided to divert to Birmingham Airport in the United Kingdom, seeking a long, dry runway with high visibility.
During the flight, the crew manually extended the landing gear. Upon landing at Birmingham, the aircraft primarily utilized the right main landing gear to mitigate damage to the left side. The landing resulted in further debris release and confirmed significant secondary damage to the aircraft's systems.
The investigation
The investigation, led by the RNSA with support from the UK AAIB, utilized Flight Data Recorder (FDR) analysis to pinpoint the moment of impact. The FDR revealed lateral acceleration peaks that could not be explained by wind or rudder inputs, coinciding precisely with the aircraft passing a section of the runway containing debris.
Investigators examined the damaged left inboard main tire and compared the failure pattern to manufacturer data. The analysis concluded that the damage was consistent with a penetration by a foreign object. Furthermore, investigators matched several pieces of debris found on the runway—including a metal cylinder and various wires—to components that had been severed from the aircraft's wheel well due to the initial tire burst.
Findings
- The primary cause of the incident was Foreign Object Damage (FOD) sustained during the takeoff roll.
- The aircraft struck debris on Runway 01, causing the left inboard main tire to burst.
- The tire burst triggered a chain of secondary damage, including broken hydraulic lines, severed electrical wires, and damaged spoiler cables.
- The loss of hydraulic system A led to the loss of several critical functions, including autopilot, certain flight spoilers, and nose wheel steering.
Safety action
- The RNSA issued a safety recommendation to Isavia to regularly review the FOD prevention program and associated procedures to ensure runways remain clear of debris.