Incident Overview
On April 20, 2009, at 1738 mountain standard time, a De Havilland DHC-8-202, registration N449YV, struck a ground power unit (GPU) with the right propeller while taxiing to parking at Phoenix Sky Harbor International Airport (PHX), Phoenix, Arizona. The aircraft was operated by Mesa Airlines as Air Shuttle flight 2957 under 14 Code of Federal Regulations Part 121, a scheduled passenger service. The flight crew, consisting of a captain and first officer, along with a flight attendant and 14 passengers, were not injured; there were no ground injuries. The airplane sustained structural damage to the right wing and fuselage.
Flight and Weather Conditions
Visual meteorological conditions prevailed for the international flight, which had departed the General Jose Maria Yanez International Airport (GYM), Guaymas, Mexico, at 1540. An instrument flight rules (IFR) flight plan had been filed.
Sequence of Events
According to the operator's written report to the National Transportation Safety Board, upon arrival at the ramp area, the flight crew had to wait just outside the gate area for marshallers to guide the aircraft to the gate. The marshaller initially displayed crossed wands, indicating a stop signal, while waiting for additional wing walkers. Once all wing walkers were in position, marshalling commenced. As the aircraft was guided into the gate area, the captain lost sight of the power cart—a situation he noted was not abnormal. He asked the first officer (FO) about the power cart's position, and the FO responded that it was clear. The captain reported that as the marshaller raised his arms to cross them (the stop signal), the number 2 propeller struck the power cart.
Phoenix Sky Harbor airport operations personnel stated that the aircraft was being marshalled to gate B24 with the aid of a marshaller and wing walkers. As the aircraft reached its final stopping point, the right propeller struck the GPU.
Damage and Contributing Factors
Federal Aviation Administration inspectors reported that the GPU was located about 7 feet aft of its required parking spot. After the propeller blades struck the GPU, the unit was pulled back toward the fuselage, causing damage to the engine, propeller, and fuselage.
Cockpit Voice Recorder Information
The cockpit voice recorder (CVR), a Fairchild Model A-100A (serial number 62478), was shipped to the NTSB vehicle recorder laboratory in Washington, D.C., for readout. The recorder was received in good condition and data was extracted normally. The model records 30 minutes of analog audio continuously on a four-channel format. A CVR group was not convened; however, a summary of events was prepared. During taxi to the ramp, the FO made several remarks about clearing the aircraft. Prior to the accident, the captain asked the FO to watch the cart, and the FO responded that they were clear. A few seconds later, the captain inquired again about clearance from the cart. As he began to repeat the question, the CVR captured the sound of impact, followed by sounds similar to engine shutdown.