Mechanical & Engine Failure · NTSB WPR15FA140
QUICKSILVER ENTERPRISES INC MXL II — Petaluma, CA
| Date | April 3, 2015 |
| Location | Petaluma, CA |
| Aircraft | QUICKSILVER ENTERPRISES INC MXL II |
| Purpose of flight | Personal |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Uncontrolled descent Aircraft structural failure |
| Pilot age | 51 |
| Pilot total time | 66 hrs · Student / very low time |
| Time in type | 65 hrs |
| Fatalities | 1 |
Probable cause
NTSB findings
- Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-(general)-Not attained/maintained - C
- Aircraft-Aircraft structures-Wing structure-Spar (on wing)-Capability exceeded - C
- Personnel issues-Physical-Impairment/incapacitation-OTC medication-Pilot - F
What happened
The student pilot was conducting a local area flight in daytime visual meteorological conditions. Multiple witnesses located near the accident site reported observing the airplane maneuvering over the area. Two witnesses reported seeing the airplane in a steep descent with the wings folded upward before it impacted the ground.
Postaccident examination of the accident site and the airplane revealed signatures consistent with a high-speed, near-vertical impact with terrain. No evidence was found of any preexisting mechanical anomalies that would have precluded normal operation of the airplane.
It's likely that while maneuvering, the pilot lost control of the airplane, which resulted in a steep descent from which the pilot did not recover. During the vertical descent, the airplane's structural capabilities were exceeded, and the wing spars failed in overstress. The pilot had applied for a medical certificate in 2003 and 2004: however, he did not provide all the information requested by the Federal Aviation Administration (FAA), and his application was denied. Review of FAA medical records revealed that the pilot had a history of a traumatic brain injury; however, based on a review of the information that the pilot provided in 2004, it is unlikely that the long term effects from the pilot's traumatic brain injury contributed to the accident.
Postaccident toxicology testing identified tetrahydrocannabinol (THC), the psychoactive component in marijuana, in the pilot's blood and various tissues, and diphenhydramine, an over-the-counter allergy and sleep aid medication, in the pilot's blood The levels of THC found in tissues suggested that it was not used recently. Therefore, it is unlikely that the pilot's use of marijuana caused impairment or contributed to the accident. However, the level of diphenhydramine found suggested that, at the time of the accident, the pilot was likely impaired by his use of diphenhydramine.