A-10 Class A Flight Mishap: An AIB Report Synopsis

Flying Safety, Nov, 2001 by Mike Baker

Class A Mishap: A mishap resulting in one or more of the following: Total mishap cost of $1,000,000 or more; A fatality or permanent total disability; Destruction of an Air Force aircraft. (AFI 91-204, Safety Investigations and Reports, paragraph 3.2.2.1.)

What you're about to read was extracted from the AIB Report of a Class A Mishap, so the information isn't "confidential" and we aren't breaking any promises of safety privilege. We have edited some of the verbiage from the Report to make for an easier read, but haven't altered any of the AIB Report facts. Ed.

Accident Summary

During a winter, early afternoon, local continuation training sortie, the A-10 mishap aircraft (MA) experienced a No. 2 engine oil system malfunction due to failure of an oil pressure indicator line, resulting in pilot shutdown of the No. 2 engine. The mishap pilot (MP) maneuvered to final approach where he con-figured for a single-engine landing in accordance with (IAW) the Dash-1 checklist. While configured on final approach, the MP experienced unfamiliar flight characteristics and initiated a single-engine go-around. During the single-engine go-around, the MP was unable to control the MA, it departed controlled flight and he successfully ejected. The MA impacted the ground less than a mile from the installation and was destroyed on impact.

The Circumstances

The mission was initially briefed and planned as a double turn (two sorties) two-ship mission, with both missions scheduled to fly to a nearby range. The wingman and the MP discussed sortie requirements, planning and briefing assignments the day prior to the sortie. The MP was the scheduled flight lead and was well prepared for the scheduled missions. Both the MP and wingman attended a mass briefing conducted by the squadron Operations Officer. NOTAMS, weather and active ranges were adequately briefed. The MP then accomplished the flight briefing for two sorties, utilizing the squadron briefing guides required by AFI 11-2A/OA10V3, A/OA-10 Operations Procedures.

Testimony from both pilots indicates the briefing was thorough and complete, covering all required briefing items. After the flight briefing the Ops Officer notified the MP and wingman that neither of their aircraft would be ready for the first sortie. When one aircraft did become available, the MP was given approval for a single-ship mission to the range with the intention of acquiring ("bootlegging) non-scheduled range time once airborne. The flight was properly scheduled, authorized and released in accordance with AFI 11-401, Flight Management.

The MA was parked in the aft section of a hardened aircraft shelter (HAS). Preflight inspection was normal with no problems noted. The aircraft forms reflected maintenance performed earlier that day. However, all references to No. 2 engine maintenance--which would later prove to be relevant to this accident investigation--performed following the MA's last flight one week before had already been transcribed and pulled from the aircraft forms. Engine start and taxi were normal.

The MP parked the aircraft at the end-of-runway (EOR) for "Last Chance" inspection and arming. Upon visual inspection of the aircraft, an EOR Maintainer noted oil/fluid dripping out of the cowling on the No. 2 engine and asked the MP if oil pressure on the No. 2 engine was within limits. The MP acknowledged that it was and asked what the problem was. The EOR Maintainer explained the oil/fluid loss to the MP and began examining the leak for tolerances. The MP offered to make a radio call for Red Ball maintenance, but the EOR Maintainer declined the offer. He subsequently cleared the aircraft for flight. According to testimony, the EOR Maintainer believed the oil/fluid leak was deicing fluid. Post-mishap research revealed that the MA had been parked inside a HAS and had not been deiced the day of the mishap.

Takeoff and departure were uneventful. Approximately 20 minutes after takeoff and at about 30 NM from the home field, the MA's Master Caution light illuminated with an accompanying "R ENG OIL PRESS" (Right Engine Oil Pressure) warning light. Oil pressure for the No. 2 engine was fluctuating between 20 and 40 psi. The MP retarded the affected throttle to a position short of idle, turned for home and radioed he was returning with an aircraft malfunction. At about 17 NM out, the MP informed Approach he was having engine trouble and declared an inflight emergency.

The MP elected to proceed towards the field's VFR entry point to have more time to complete the descent and accomplish checklist items. While en route, he referenced the Oil System Malfunction checklist, noted that No. 2 engine oil pressure had dropped to 5 psi ( /- 3 psi) and shut it down IAW the checklist. The MP informed Tower that he was now single-engine and requested a 360-degree turn at the VFR entry point to make sure he completed checklist items. While holding in a right turn he informed the Supervisor of Flying (SOF) he was cleaning up all checklist items and would fly a single-engine, straight-in approach to a full stop. The SOF acknowledged and asked the MP to let him know if he needed further assistance. The SOP then ran the SOF emergency checklist and notified the agencies/persons listed. According to testimony, the MP did not complete the Single-Engine Landing checklist or contact Squadron Operations. The MP then departed the VFR entry point and set up for the single-engine approach to the runw ay.