What happened
On September 24, 2003, a Robinson R22 Mariner II, registration G-STRO, was performing a commercial aerial photography mission near Porto Petro in the Balearic Islands. The crew, consisting of a pilot and a photographer, was flying at a very low altitude—approximately two meters above the water—to capture images of boats navigating the coastline. To facilitate better photography angles, the helicopter's left-hand door had been removed.
While the aircraft was positioned behind a sailing boat to photograph its stern, the pilot was maintaining flight using significant right-pedal input to keep the aircraft out of trim. As the photography session concluded, the pilot attempted to transition into an acceleration maneuver for ascent. During this phase, the pilot applied left pedal to compensate for the previous trim and forward cyclic to increase speed. This combination of control inputs, along with the aircraft moving from the visible wake of the boat into a smoother sea surface, led to a sudden loss of altitude. One of the helicopter's skis struck the water, causing the aircraft to impact the surface and capsize. The cabin became submerged, but both occupants managed to escape the aircraft and were rescued by the very boat they had been photographing.
The investigation
The investigation examined the flight dynamics of the Robinson R22 Mariner II during the transition from hovering/low-speed maneuvering to acceleration. Investigators analyzed the impact of control inputs, specifically the use of left pedal and forward cyclic, on the aircraft's vertical stability. The investigation also looked into the aircraft's configuration, noting it was equipped with floats for water operations.
Furthermore, the investigation scrutinized survival equipment and procedures. There were conflicting reports regarding the presence and use of life jackets. While the pilot stated they were worn, witnesses and flight documentation provided no evidence of their presence. The investigation also reviewed the crew's ability to evacuate the submerged cabin and the necessity of emergency training for non-flying crew members.
Findings
- The primary cause of the accident was a successive loss of height resulting from simultaneous control inputs (left pedal and forward cyclic) that were not sufficiently corrected with increased power.
- The pilot may have misjudged the aircraft's altitude as it moved from the identifiable wake of the boat to a smoother sea surface, losing visual height references.
- The aircraft suffered significant damage, including a severed tailboom and damaged main rotor blades, caused by the rotor assembly striking the tail structure during the impact.
- There was a lack of clarity regarding the availability of life jackets, which are essential for preventing spatial disorientation and ensuring buoyancy during water ditching events.
- The removal of the left door, while intended to aid photography, altered the aircraft's configuration during the low-altitude maneuver.