ASN Wikibase Occurrence # 121065
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| Date: | Friday 11 March 2011 |
| Time: | 13:43 |
| Type: |  Cessna 310R |
| Owner/operator: | Hudson Management Corporation |
| Registration: | N310JR |
| MSN: | 310R1253 |
| Year of manufacture: | 1977 |
| Total airframe hrs: | 5516 hours |
| Engine model: | Continental IO 520 SERIES |
| Fatalities: | Fatalities: 1 / Occupants: 1 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Smyrna, Tennesse -
 United States of America
|
| Phase: | En route |
| Nature: | Ferry/positioning |
| Departure airport: | Smyrna Airport, TN (MQY/KMQY) |
| Smyrna Airport, TN (MQY/KMQY) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
Shortly after departure, the airplane entered a rapid, full-power, near-vertical descent from about 2,700 feet above ground level to ground impact. The elevator trim actuator was found in the full tab-up or airplane nose-down position after the accident. The flight was the second flight of the day and was the fourth in a series of maintenance acceptance flights after the installation of a new avionics suite and a new autopilot system. Before the accident flight, all of the features of the autopilot system tested satisfactorily on the ground but did not yet function as designed in flight, as the airplane demonstrated a pitch-porpoise tendency when the altitude hold feature was engaged.
According to the technician who performed the installation and troubleshooting work on the airplane, he had accompanied the pilot on the first flight that day and had spoken to an autopilot manufacturing representative upon their return. Another troubleshooting procedure was performed, the technician left for lunch, and the pilot departed alone on the accident flight. When describing a previous test flight, the technician stated that the pilot worked the yoke against the autopilot, and, in response, the autopilot ran the elevator trim to the full nose-down position. The pilot responded by swiping both panel-mounted master switches to the off position (autopilot on/off switch and the trim on/off switch) then attempting to trim the airplane with the electric trim that he had just disabled. According to the technician, the pilot yelled at him to turn the system off, and the technician responded that it was off. He said that the pilot’s actions scared him and demonstrated to him that the pilot really didn't have control of the airplane. He noted that, "After the flight, I told [the pilot] he needed to go back and get in the books and learn to operate the system. He seemed very disoriented with the new technology on this flight and previous flights."
Based on the available evidence, it is likely that, after autopilot engagement, the airplane pitched down as a first action of the pitch porpoise, which may have still existed as a discrepancy in the autopilot operation. In response to the downward movement of the airplane, the pilot likely pulled back on the yoke in an effort to arrest the airplane's descent. As a result, the autopilot would have commanded the trim further toward the nose-down position. Such a scenario would require a greater and ever-increasing physical effort by the pilot to overcome the growing aerodynamic force that would result from the nose-down pitch and increasing speed of the airplane. The pilot may have removed one hand from the yoke to again reach for the panel-mounted trim and/or autopilot master switches. With that action, discounting any physical problem, he may have lost his single-handed grip on the control yoke, and the airplane descended in an unrecoverable nose-down attitude.
Probable Cause: The pilot's improper response to a known autopilot pitch divergence anomaly. Contributing to the accident was the pilot's decision to perform a test flight on a system for which he lacked a complete working knowledge.
Accident investigation:
 |
|
Sources:
NTSB
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 11-Mar-2011 17:58 | bizjets101 | Added |
| 12-Mar-2011 08:17 | bizjets101 | Updated [Total fatalities, Total occupants, Source] |
| 17-Mar-2011 14:58 | harro | Updated [Embed code] |
| 09-Feb-2012 01:01 | Anon. | Updated [Total fatalities, Total occupants, Source, Embed code] |
| 09-Feb-2012 01:02 | harro | Updated [Time, Nature, Departure airport, Destination airport, Source, Embed code, Narrative] |
| 09-Feb-2012 01:02 | harro | Updated [Phase, Embed code] |
| 11-Mar-2012 16:02 | Geno | Updated [Time, Source, Narrative] |
| 21-Dec-2016 19:25 | ASN Update Bot | Updated [Time, Damage, Category, Investigating agency] |
| 27-Nov-2017 16:45 | ASN Update Bot | Updated [Operator, Other fatalities, Nature, Departure airport, Destination airport, Source, Narrative] |
| 12-Mar-2024 18:33 | Anon. | Updated [Nature, Departure airport, Destination airport] |
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