What happened
During the initial climb-out phase of flight, an MD-80 was struck by lightning. Shortly after the strike, dark smoke began entering the forward area of the passenger cabin. In response to the smoke, the crew declared an emergency. To combat the fire, flight attendants and a passenger worked together to cut a hole in the overhead panel and discharged two handheld fire extinguishers. The aircraft landed uneventally, and an emergency evacuation was performed without incident; all occupants were not injured.
The investigation
Post-flight examination of the aircraft identified that a deactivated navigational antenna, located in the tail cone, had been the point of impact for the lightning strike. Two coaxial cables, which were tied together with tie-wraps, were attached to this antenna and ran into the cabin along the upper left side of the fuselage, positioned between the overhead panels and insulation blankets.
The investigation found that the cable ends, located above row 7AB in the area of the most significant fire damage, had been mechanically cut. The insulation near these cable ends showed evidence of cratering and burrowing. These cable ends were neither grounded nor protected.
It was determined that the cables had been partially removed following an engineering change order (ECO) created by the operator to facilitate the installation of a more advanced system. While the existing procedure required the cable ends to be covered with heat shrink tubing or similar material, this had not been performed. At the time of the incident, 57 of the operator's 259 MD-80 aircraft had undergone this partial cable removal, while 21 aircraft still utilized the full Omega antenna system.
Findings
Following the event, the operator implemented a revised engineering change order. The new procedure requires that the cable running down the vertical stabilizer be cut and grounded to the structure in the aft accessory compartment. Additionally, the portion of the cable passing through the aft pressure bulkhead is to be removed and the feed-through sealed to protect the cable from lightning damage. As of January 11, 2001, this revised ECO had been applied to all 78 relevant aircraft.