NTSB Factual Report

On June 26, 2004 about 0430 mountain standard time, an Eurocopter AS350B3, N5226R, experienced a hard landing in Cibicue, Arizona. Native American Air Ambulance was operating the helicopter for a positioning flight under the provisions of 14 CFR Part 91. The airline transport pilot and two medical crewmembers were not injured; the helicopter sustained substantial damage. The emergency medical flight departed Show Low Regional Airport, Show Low, Arizona, about 0400, with a planned destination of Cibicue. Visual meteorological conditions prevailed, and a company flight plan had been filed.

On July 4, 2004, damage to the tail boom was discovered during routine maintenance activities. The damage was described as dimples or depressions in the tail boom skin just aft and below the aft VOR antenna mount. The skin abnormalities were predominantly on the right side of the boom and were not obviously discernable unless viewed from aft looking forward along the boom skin. Eurocopter provided an on-site evaluation of the boom and determined that the damage was structural (requiring major repair) and was consistent with the expected damage pattern resulting from a hard landing. The operator then undertook an investigation to determine when the damage had occurred by interviewing the flight crews of all flights prior to July 4. The only flight that had any anomaly associated with it was the June 26, 2004, flight to Cibecue.

In a written report, the pilot of the June 26 flight stated that he and a medical crew were dispatched from Show Low to pickup a stabbing victim at Cibecue for transport to a hospital in Scottsdale, Arizona. Several days prior, the pilot had landed at the same landing zone, a baseball field in Cibicue, and was familiar with the area. The last time he had landed and departed from the landing zone he encountered blowing dirt, and in an effort to adequately prepare, he briefed the medical crewmembers of the anticipated dust cloud.

As he approached the baseball field, the pilot located a small patch of grassy terrain and opted to touchdown there. About 3 feet above ground level, as the helicopter slowed to about 10 knots, a dust cloud began to formulate. The helicopter continued to descend and made a "firm" touchdown on the right skid, followed almost immediately by the left. He thought that the touchdown was not unusually hard, and added that he had experienced similar touchdowns in the same make and model helicopter.

After landing, the pilot apologized to the crew that the landing was not as smooth as normal, and explained that is was necessary due to the dust. He shutdown the helicopter and egressed, in an effort to complete a walk around inspection. He noted no mechanical irregularities or damage to the helicopter.

A medical crewmember reported in a written statement that on final approach he felt as though the helicopter was descending faster than normal. As the helicopter came into ground effect, a significant amount of dust was stirred up, diminishing visibility. The skids then touched down with "significant" force.

The operator reported no preimpact mechanical malfunctions of failures with the helicopter.

NTSB Probable Cause

the pilot's failure to maintain a proper decent rate during the landing approach and misjudged landing flare, which resulted in a hard landing. A factor in the accident was the brownout conditions created by the dust cloud that interfered with the pilot's perception of proximity to the ground.