What happened
At 2059 MDT, a lightning strike caused a power outage within the air traffic control (ATC) tower. While electrical power was eventually restored, several pieces of equipment, including the radar computer and voice recorders, remained inoperative for a period of time.
At approximately 2 elapsed minutes after 2121 MDT, the pilot of a Cessna 402B, registration N25BH, contacted ground control (GC) and received clearance to taxi from the executive hangar to runway 28R for takeoff. Roughly one minute later, a Piper PA-34, registration N3408Q, contacted ground control and was cleared to taxi from the regional hangar to the departure runway. The weather at the time consisted of rain and dark night conditions.
As the Cessna 402B proceeded eastbound on the parallel taxiway toward runway 10L/28R, the Piper PA-34 was exiting an adjacent ramp area where other aircraft were parked. The two aircraft converged at a taxiway intersection, and neither pilot identified the other in time to prevent a collision. The right propeller of the Piper PA-34 struck the left wingtip and fuel tank of the Cessna 402B, causing a fuel spill and substantial damage to the Cessna's left wing. The Piper PA-34 sustained minor damage to its right wing. No injuries were reported.
The investigation
The investigation determined that ground control did not issue any further advisories to the aircraft after the initial taxi clearances were provided. Additionally, an alarm resulting from an equipment failure distracted the tower controller(s), which prevented them from visually identifying the Piper PA-34 during its movement.