What happened
On April 17, 1995, a Cessna T-337G Pressurized Skymaster, registered as N6CY, attempted a short takeoff from Portimão Aerodrome, Portugal, bound for Ibiza. The aircraft was occupied by the pilot and one passenger.
During the takeoff roll, the pilot initiated the takeoff run approximately 80 meters from the runway threshold. After traveling 560 meters, the pilot realized the aircraft lacked sufficient speed and power to rotate, prompting an attempt to abort the takeoff. During the braking process, the aircraft began to veer to the left. In an effort to regain directional control and reduce speed, the pilot applied heavy braking to the right main wheel, causing the aircraft to leave the paved surface.
The aircraft continued along the left shoulder of the runway for 115 meters. Due to the sloping terrain near a drainage ditch, the aircraft lifted slightly before striking a 3.5-m high embankment. The impact, involving the nose gear, the left main gear, and a propeller blade, caused the aircraft to capsize. The fuselage came to rest inverted and partially submerged in the Alvor estuary. Both occupants sustained fatal injuries.
The investigation
The GPIAAF investigation focused on the engine performance, fuel system configuration, and the pilot's decision-making. Investigators examined the fuel selector valves and found that the valve for the front engine was incorrectly set to the right tank. This configuration meant both engines were drawing fuel from the same collector tank, a practice prohibited by the manufacturer because it can lead to a dual engine failure due to insufficient fuel flow.
While no primary mechanical failure was identified, the investigation noted mediocre maintenance standards, including improper engine tuning and the use of non-eligible components. Furthermore, the pilot's experience with this specific aircraft type was limited to only a few familiarization flights.
Findings
- The primary cause of the accident was a partial power loss in both engines caused by the incorrect selection of the fuel selector valve for the front engine, which improperly drew fuel from the same reservoir as the rear engine.
- The pilot's decision to abort the takeoff was made too late; by the time braking was applied, there was insufficient runway remaining to stop the aircraft safely.
- The aircraft was operating in a configuration that violated the manufacturer's instructions, leading to an insufficient fuel flow rate.
- The pilot had limited experience with the Cessna T-337G.