What happened
On 27 April 2007, an Easy Raider, registration G-CCJS, was performing a series of flight tests near Andreas Airfield, Isle of $\text{Man}$, to secure an initial Permit to Fly. The aircraft, powered by a Jabiru 1600 engine, was being flown by a pilot with 5,000 total flying hours. The flight was intended to test the aircraft's climb performance at approximately 90% of its maximum takeoff weight.
Shortly before 1100 UTC, the aircraft departed from Runway 05. While the takeoff was initially reported as normal, the subsequent climb was sluggish, achieving a rate of only about 300 feet per minute. As the aircraft encountered rising terrain ahead, the pilot attempted to turn back toward the airfield. During this maneuver, the aircraft began to sink at approximately 200 feet above ground level, likely due to a downdraft caused by wind interacting with nearby hills. The aircraft subsequently stalled and entered an incipient left-hand spin, impacting the ground in a steep, nose-down attitude. The impact resulted in serious injuries to both the pilot and the passenger, and the aircraft was destroyed.
The investigation
The AAIB examined the aircraft's performance and the conditions during the flight. It was noted that the aircraft required continuous right rudder to maintain directional control, a characteristic the pilot had observed during a previous solo flight. The investigation also reviewed the use of a passenger as an observer during the test flight. While the British Microlight Aircraft Association (BMAA) allows for approved observers to assist with monitoring, the investigation looked into the risks associated with such arrangements during performance testing.
Findings
- The aircraft's climb performance was inadequate to maintain sufficient terrain clearance with the rising ground ahead.
- The pilot maintained a steep climbing attitude with a low airspeed while attempting to correct a constant left yaw with right rudder.
- A combination of rising terrain, poor climb performance, and wind-induced downdrafts led to the stall.
- The aircraft's stall speed was likely increased by the simultaneous application of rudder input and a bank angle.