VFR into IMC · NTSB WPR19LA058
Beech A36 — Colusa, CA
| Date | January 7, 2019 |
| Location | Colusa, CA |
| Aircraft | Beech A36 |
| Purpose of flight | Personal |
| Conditions | Day · Instrument Meteorological Cond |
| Phase / occurrence | Initial climb Collision with terr/obj (non-CFIT) |
| Pilot age | 66 |
| Pilot total time | 1,500 hrs · Experienced |
| Time in type | Unknown |
| Fatalities | 2 |
Probable cause
NTSB findings
- Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C
- Personnel issues-Psychological-Perception/orientation/illusion-Spatial disorientation-Pilot - C
- Environmental issues-Conditions/weather/phenomena-Ceiling/visibility/precip-Below VFR minima-Effect on operation
What happened
The pilot, who did not possess a current medical certificate, departed in instrument meteorological conditions on a cross-country flight with a passenger onboard. A witness at the departure airport reported that at the time of takeoff, the cloud ceiling was about 500 ft above ground level with visibility of about 1 mile. Radar information revealed that the airplane turned to a southwesterly heading after departure, consistent with a heading toward their intended destination. The data showed that about 10 seconds after takeoff, as the airplane ascended through about 725 ft mean sea level (msl), a right turn was initiated. During the initial portion of the turn, the airplane continued to ascend to about 825 ft msl, where it remained for about 7 seconds. The airplane then began a descent while remaining in the right turn until impact.
Maneuvering the airplane in restricted visibility placed the pilot in conditions conducive to the development of spatial disorientation. The accident circumstances, including the tightening descending turn, and the subsequent high-energy impact, are consistent with the known effects of spatial disorientation. Additionally, examination of the engine revealed no evidence of any preexisting anomalies that would have precluded normal operation. Part of the flight control system was highly fragmented and could not be examined; however, the portions that remained intact did not exhibit any preexisting anomalies. Therefore, it is likely that the pilot was experiencing the effects of spatial disorientation when the accident occurred.
The pilot’s autopsy revealed severe cardiac disease, and although incapacitation as a result of this was possible, the pilot's loss of control suggests spatial disorientation was a more likely initiating event. Thus, it is unlikely that any symptoms from the pilot's severe cardiac disease contributed to this accident. The pilot also had bipolar disorder, but the extent of symptoms and whether they contributed to the accident could not be determined from the available information. However, the pilot had an established history of using medications to control the disease; therefore, some of the negative effects may have likely improved.