CESSNA 310H — Yeehaw Junction, FL

What happened

The noninstrument-rated pilot, copilot, and the passenger were attempting to return from the Bahamas to Florida; a weather front was passing over Florida at the time. The copilot had contacted flight service before the initial flight and learned of thunderstorms in the area; the flight had to divert from its planned destination. The copilot contacted flight service before a second flight, and the flight service specialist advised that visual flight rules flight was not recommended due to low cloud ceilings and visibility. The pilot decided to land at an airport closer to his destination. At that airport, the copilot again contacted flight service and remarked that he was trying to figure out how to "scud run" to get home. He also spoke to his wife, who told him that the weather "was bad" at their final destination, and she reported that she thought they would delay their flight until the next day. Even though his calls to the weather briefer and his wife indicated adverse weather along the route of flight and at the destination, the copilot likely advised the pilot to continue the flight. About 20 minutes into the flight, the copilot contacted the Orlando approach controller and reported that they had inadvertently entered instrument meteorological conditions (IMC). The controller instructed him to set the transponder code to 0311 so that she could locate the airplane and then to contact Miami Center; however, no further communications were received from the copilot.

Review of radar data revealed that, shortly after contacting Orlando Approach control, while the controller was attempting to locate the airplane, it descended in three left circuits from 8,900 feet mean sea level (msl) to 1,800 feet msl. It subsequently made a right circuit, descended to 900 feet msl, and continued to proceed toward the destination airport, eventually descending to 200 feet msl. The last 3 minutes of radar data showed the airplane flying at an altitude between 100 and 200 feet msl. The final radar target was recorded while the airplane was in a left circuit at 200 feet, about 1/8 mile southwest of the accident site. The wreckage was located the following day in a heavily wooded, deep water, swamp area, and no debris path was observed. Given the radar data and the existence of marginal visual conditions, moderate rain, and the pilot not being instrument rated, it is likely that the pilot experienced spatial disorientation.

Two toxicological tests revealed measurements of diphenhydramine in the pilot's blood at levels within or well above the therapeutic range indicating that the pilot likely took the drug about 2 to 3 hours before the accident. Diphenhydramine causes marked sedation and is also classed as a depressant and used as a sleep aid. Altered mood and impaired cognitive and psychomotor performance may also be observed. Therefore, it is very likely that cognitive and psychomotor impairment caused by diphenhydramine contributed to the pilot's poor judgment about flying in marginal weather conditions and may have further impaired his ability to appropriately cope with relatively unfamiliar flying conditions when he flew into IMC.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.