What happened
On September 4, 2006, an R-44 helicopter, registration PP-MPR, was performing taxi maneuvers at the Campo de Marte Aerodrome (SBMT) in São Paulo. After approaching helipad number two, the pilot taxied toward the LCR Táxi Aéreo Ltda. hangar.
While executing a turn to position the aircraft in a parking spot, the pilot attempted to use a non-homologated area marked by a painted circle. During this maneuver, the aircraft's tail rotor struck one of the main rotor blades of a stationary helicopter, registration PT-HNC. The impact caused significant material loss to the tail rotor blades and induced severe dynamic imbalance. This vibration was so intense that the tail rotor and the end of the tail cone detached from the aircraft. Despite the structural failure, the pilot was able to land the aircraft safely and escaped without injuries.
The investigation
CENIPA's investigation focused on the circumstances leading to the collision and the use of the unauthorized parking area. Investigators found that while the hangar's official contract with INFRAERO authorized four parking spots, a fifth spot had been painted on the pavement. This fifth spot was undersized, with a diameter of only 5.30 meters, which was significantly smaller than the 11.65-meter length of the R-44 and failed to meet the minimum dimension requirements established by Brazilian aviation regulations (RBHA 91 and Ordinance No. 18/GM/1974).
The investigation established that the pilot was familiar with the area and had previously used this specific non-homologated spot. The pilot chose this location to facilitate easier towing of the aircraft to the hangar for overnight parking, despite a valid, authorized spot being available nearby.
Findings
- Improper use of unauthorized area: The pilot intentionally selected a non-homologated parking spot that did not meet regulatory size requirements.
- Inadequate pilot judgment: The pilot failed to properly assess the clearance required for the tail rotor during the turn and failed to evaluate the risks of using an undersized spot, as the benefits of easier towing were disproportionate to the collision risk.
- Non-compliance with regulations: The pilot's actions violated safety procedures regarding aircraft separation during taxi and the use of approved landing/parking areas.
- Infrastructure issues: The existence of the improperly marked fifth spot acted as a latent condition that could mislead pilots into using an unsafe area.
- Loss of control during taxi: The pilot allowed the aircraft to lose altitude during the taxi maneuver, leading to the contact with the parked PT-HNC.