Amateur-built RV-6 N30AK accident near Concord, California

Probable cause

A total loss of engine power during takeoff due to a separated fuel line and the pilot’s subsequent failure to maintain control of the airplane. Contributing to the accident were the pilot's medical condition and the effects of multiple impairing substances.

NTSB analysis

The pilot was conducting touch-and-go landings and takeoffs and had completed several. After the last takeoff, the airplane climbed to about 100 ft mean sea level (msl), and the engine lost power. The airplane’s nose lowered, and engine power momentarily returned. The airplane’s nose then pitched up and, about that time, the engine lost total power. The airplane subsequently banked left and entered a near-vertical descent to the ground, consistent with an aerodynamic stall.

Postaccident examination of the engine revealed that the fuel pump output line B-nut, which connects to the carburetor fuel inlet filter screen fitting, was detached. The B-nut exhibited no evidence of impact-related damage, and the threads on both the B-nut and the corresponding fitting were found to be intact and undamaged. The lack of damage on the threads and the in-flight detachment suggest that the B-nut was not properly torqued. There was no record of any recent maintenance having been done to that area of the engine, and the engine had operated only about 40 hours since its last condition inspection more than a year before the accident. Thus, it is likely the pilot may have performed airplane maintenance which was not reflected in the maintenance logbooks. Examination of the flight controls revealed no evidence of any preimpact mechanical malfunction or failure that would have precluded normal operation.

The pilot’s medical history indicated that he had sustained a severe traumatic brain injury (TBI) in 2000. Severe TBIs commonly result in permanent cognitive damage, such as impairments in attention, executive functioning, and decision-making; these may include diminished reaction time and impaired reasoning and judgment. Also, the pilot’s toxicology results identified multiple potentially impairing substances, which could have adversely and unpredictably interacted with one another to worsen impairment, as well as a medication commonly used to treat moderate to severe symptoms of dementia, a potentially impairing condition.

The loss of engine power may have saturated the pilot’s attention, leading to his failure to maintain control of the airplane. Also, the combination of the pilot’s medical conditions and use of multiple impairing substances likely adversely affected his ability to react accordingly to maintain airplane control after the engine power loss.

In 2000 and 2001, the FAA denied the pilot medical certification due to his TBI and continued neurocognitive deficits. However, beginning in 2003, the pilot subsequently applied for (and obtained) multiple third-class medical certificates over the years after providing the FAA with a different social security number, different spelling of his name, and nondisclosure of his disqualifying medical history.

In 2012, the FAA identified the pilot’s social security number discrepancy and merged his two medical files but did not identify the pilot’s disqualifying medical history, and it continued to issue him medical certificates as recently as 2023. Whether the pilot would have continued to fly if the FAA had detected his disqualifying medical history and again denied him a medical certificate cannot be known.

Text from the NTSB. Open the NTSB docket for WPR24FA080 for the full record.