DEN00FA175 · Beech S35

Witnesses described the airplane as 'attempting a full throttle climb' at 'low altitude' before rolling inverted and descending in a near vertical attitude. The two pilots were brothers and both were retired airline pilots. The left seat pilot owned a share in the airplane and had logged 50 hours in make/model. The right seat pilot had flown light aircraft previously, but had never flown the Beech S35. Wreckage examination disclosed the landing gear was up and the flaps were fully deployed. The throttle, mixture, and propeller controls were full forward. The throwover control wheel was in the right position. According to pilots familiar with the S35 Bonanza, it has conventional flight and stall characteristics in uncoordinated flight or in a cross-controlled stall. Chapter 5-2 of FAA's 'Airplane Flying Handbook' (FAA-H-8033-3) states: 'In a cross-control stall, the airplane often stalls with little warning. The nose may pitch down, the inside wing may suddenly drop, and the airplane may continue to roll to an inverted position. This is usually the beginning of a spin. It is obvious that close to the ground is no place to allow this to happen. Recovery must be made before the airplane enters an abnormal attitude (vertical spiral or spin); it is a simple matter to return to straight-and-level flight by coordinated use of the controls. The pilot must be able to recognize when this stall is imminent and must take immediate action to prevent a completely stalled condition. It is imperative that this type of stall not occur during an actual approach to a landing, since recovery may be impossible prior to ground contact due to the low altitude.'

Verbatim NTSB analysis and probable cause from the NTSB dataset