What happened
On November 29, 2013, at approximately 09:30 JST, an ANA Wings Co., Ltd. Bombardier DHC-8-402, registered JA462A, was conducting a scheduled flight from Fukuoka Airport to Fukue Airport. The aircraft was carrying 36 passengers and 5 crew members. During the descent phase, while flying at an altitude of roughly 5,300 feet approximately 20 km northeast of Fukue Airport, the crew observed a bright flash and heard a loud bang.
While the flight crew initially identified no immediate flight instrument abnormalities, a post-flight inspection revealed substantial damage. The strike caused five dents on the outer skin of the upper left nose access panel and deformed the underlying internal structure. Additionally, six rivet heads on the same panel were burned, and several latches on the nose access panels were found in the open position. Electrical damage was also noted on the radome, the left wing tip static discharger, the right elevator tip static discharger, and the APU silencer.
The investigation
The JTSB investigation examined the meteorological conditions, the aircraft's flight data, and the physical damage to the airframe. Investigators reviewed weather radar data and lightning strike observations from Franklin Japan, which confirmed a lightning strike occurred near the flight path at 09:30:12. The investigation also analyzed the structural deformation of the nose section and the state of the aircraft's latches following the event.
Findings
- The meteorological environment was characterized by a wintry pressure pattern with a passing trough, leading to widespread, low-altitude cumulus clouds. While these clouds did not indicate heavy rainfall on radar, they were capable of generating lightning.
- The damage to the nose skin and internal structure was likely caused by an extremely powerful shockwave generated by the lightning discharge. This shockwave, resulting from the rapid expansion of air, was strong enough to dent the metal and potentially force the access panel latches inward.
- The burned components, including the radome, wing tip, and APU silencer, were the result of the electrical current finding a conductive path through the aircraft's structure during the strike.