What happened
On May 23, 2012, an EC 135 T1, registration PP-MZZ, was performing a transport flight from a clearing in Amazonas to the Itapiranga Base. The aircraft was carrying the pilot and six passengers. During the final approach to the landing site, a MASTER CAUTION light illuminated on the Cockpit Display System (CDS), specifically indicating a fault with the aft fuel pump.
While the pilot was focused on the upper panel to perform the necessary shutdown procedure for the equipment, the tail rotor struck the branches of a tree located approximately 300 feet above the landing area. Despite the impact, the pilot maintained control of the aircraft and completed the landing without further incident. All seven occupants escaped the aircraft uninjured, though the helicopter sustained substantial damage to the tail boom section, including a broken debris detector and a damaged external cargo mirror.
The investigation
CENIPA investigators examined the aircraft's fuel system and the operational environment at the Itapiranga Base. The investigation confirmed that the fuel pump warning was not caused by a mechanical failure, but rather by the low fuel level in the main tank. With only approximately 20kg of fuel remaining in the main tank, the pump was likely operating without sufficient fuel flow, triggering the warning.
The investigation also reviewed the landing procedures at the site. While an advisory suggested using the Eastern Sector for approaches to avoid obstacles, a physical marker at the helipad recommended a 270-degree heading. The pilot had approached on a 225-degree heading, which was 45 degrees offset from the recommended path.
Findings
- The pilot's attention was diverted from the flight path to the instrument panel to address the MASTER CAUTION warning.
- The low fuel level in the main tank caused the fuel pump warning to trigger.
- The pilot's approach heading of 225 degrees deviated from the 270-degree heading indicated at the landing site.
- The pilot's lack of familiarity with the specific terrain and obstacles in the Amazon region may have contributed to an excessively low approach slope.
- The approach was conducted with a tailwind, which may have prompted a lower descent rate to compensate for the aircraft's tendency to overshoot the landing point.