What happened
While taxiing for departure, two Cessna 402C aircraft were involved in a collision. The crew of N26514 reported that they had taxied to the end of the runway and stopped at the hold short line. Approximately one minute later, the crew felt a large jolt from behind.
The pilot of N812AN stated that as she approached the rear of the Air Vegas aircraft, she applied the brakes, but the application had no effect on the speed of the aircraft.
The investigation
A company pilot who operated N812AN in revenue line operations on February 11 reported experiencing a fading of the left brake pedal during landing. While the problem did not repeat after reapplication of the pedal, an FAA A & P mechanic examined the brake system of N8012AN on the day of the accident.
The mechanic's written report determined that the left brake master cylinder was faulty. The investigation found that while the left brake operated normally under hard braking, less forceful applications caused the pedal to gradually sink to the bottom of its travel, which prevented the pressurization of the left brake system.