Accident Details
On September 24, 2019, at about 1002 eastern daylight time, a Cessna 337G, registration N108LS, was substantially damaged in an accident near St. Augustine, Florida. The private pilot and designated pilot examiner on board sustained serious injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a flight test for the pilot's multi-engine rating.
Flight Sequence
The pilot and examiner departed for the flight portion of the practical test. After completing air work, they returned to the departure airport for takeoffs and landings. Following a landing, the pilot cleared the runway and requested traffic pattern work. The tower controller advised a five- to ten-minute delay, which the pilot acknowledged, and the airplane held short of the runway. During the wait, the examiner inquired about the rear engine temperature; the pilot determined it was within limits. The controller then cleared the airplane for an expedited takeoff.
Takeoff and Loss of Climb Performance
The pilot reported all instrument indications were normal. The airplane accelerated to 85 mph and rotated. Shortly after rotation, the pilot stated the airplane "discontinued climbing." The examiner then assumed control. Unable to land on the remaining runway, the examiner attempted to fly out of ground effect but the airplane would not maintain altitude. He initiated a left turn toward an open area on the airport, during which the airplane began to descend. The wings were leveled and the airplane slowed as it approached the touchdown area, impacting terrain with a descent rate of about 400 to 600 feet per minute.
Post-Accident Examination
Examination by an FAA inspector before recovery revealed that the rear propeller blades were in the feathered position and the rear engine cowl flaps were open. The front propeller blades exhibited considerable distortion and had rotated in the hub. In the throttle quadrant, the throttle and propeller controls for both engines were full forward, while both mixture controls were in the idle cut-off position. The airplane was recovered for further engine analysis.
Engine Examinations
The rear engine was examined and tested. No preimpact failure or malfunction of the engine or its systems was found. An external fuel tank was plumbed into the airframe boost pump fuel inlet. The engine started normally and ran without hesitation. During a full-power run, the No. 3 cylinder head temperature approached the maximum limit, so power was reduced. Subsequent full throttle applications showed no anomalies. The rear engine was secured with the mixture and the propeller remained in a normal low pitch position.
The front engine could not be operationally tested due to damage to the oil filter adapter. However, examination of the front engine and its systems revealed no discrepancies that would have precluded normal operation.
Recorded Data Review
Review of engine monitor data showed that during the accident takeoff, the front engine was within 100 rpm of its rated takeoff power, while the rear engine was at 137 rpm and remained at that value for the remainder of the recorded data. Additionally, while awaiting takeoff clearance on the ground, the rear engine oil temperature reached a maximum of 227°F, 13°F below the maximum red line.
Placard and Owner's Manual Information
A placard on the instrument panel stated: "Do not initiate single engine take-off." The owner's manual recommended advancing the rear engine throttle ahead of the front engine throttle during takeoff and periodically monitoring fuel flow and rpm. If either indicator was below normal, the takeoff should be discontinued immediately while sufficient runway remained. The manual also noted that full throttle checks on the ground are not recommended.