Analysis of recent civilian helicopter accidents

¶ … Civilian Helicopter Accidents

This is a template and guideline and is not to be used as a final, turn-in paper.

Accident occurred Sunday, June 29, 2008 in Flagstaff, AZ (NTSB, 2009)

Two emergency medical helicopters -- N407MJ and N407GA -- from two different companies on approach to Flagstaff, AZ medical center (FMC) helipad to drop off patients struck each other in flight and all seven people aboard were killed.

As they approached the medical center, both pilots contacted their communications centers and provided position reports. The FMC communications center advised N407GA that N407MJ would also be dropping off a patient at the medical center. The FMC communications center also advised N407MJ's communications center that N407GA would be landing at the medical center.

However, N407MJ's comm. center did not inform N407MJ of that fact. It was not required to do so.

Three minutes before the collision N407GA dropped off a medical crewmember at the local airport five miles south of the medical center. The pilot then took a direct route from the airport to the medical center, approaching from the south. According to the helipad approach procedures, he should have approached from an easterly direction.

N407MJ approached from a north easterly direction, the pilot scanning the typical approach paths to the medical center as outlined in the noise abatement procedures. Therefore, he did not see N407GA approaching from the south.

When the aircraft collided, 1/4-mile east of the helipad, both pilots were close enough to the helipad that their attention was focused on landing. There were no communications from either pilot either prior to or after the collision.

Wreckage showed that N407MJ's tail rotor contacted the forward fuselage of N407GA, and N407GA's rotor blades contacted and severed N407MJ's tail boom. There was no evidence of any pre-impact structural, engine, or system failures.

NTSB Probable Cause

"Both helicopter pilots' failure to see and avoid the other helicopter on approach to the helipad. Contributing to the accident were the failure of N407GA's pilot to follow arrival and noise abatement guidelines and the failure of N407MJ's pilot to follow communications guidelines" (NTSB, 2009).

Accident Occurred Sunday, June 8, 2008 between Huntsville and Houston, TX (NTSB 2, 2008)

An Emergency Medical Services (EMS) helicopter was dispatched from Huntsville, TX. Another EMS operator had aborted the mission an hour and a half prior due to low clouds and poor visibility due to fog enroute. He did not, however, issue a Pilot Report (PIREP) of poor weather to the FAA.

The second EMS helicopter pilot questioned why the previous operator had aborted, but weather stations were reporting VFR conditions, so the second flight was accepted.

The wreckage was found the next morning in rugged, forested terrain in the exact location the first operator had reported the low clouds and poor visibility due to fog.

Sheared tree tops indicated that the initial impact occurred with the helicopter's main rotor blade, in a straight, nose low attitude. The flight path terrain was dark, without surface reference lights, and there was no moon. The helicopter was equipped with Aviation Night Vision Imaging System and radar altimeter. The pilot was not wearing the night vision goggles. There were no anomalies with the aircraft airframe, engine or other systems.

NTSB Probable Cause

"The pilot's failure to identify and arrest the helicopter's descent, which resulted in its impact with terrain. Contributing to the accident was the pilot's inadvertent flight into instrument meteorological conditions, and the limited outside visual reference due to the dark night conditions, low clouds, and fog" (NTSB 2, 2008)

Accident occurred Tuesday, June 13, 2000 in TOPEKA, KS (NTSB 3, 2001)

The police helicopter was providing night airborne surveillance support to a Topeka, Kansas, police ground unit, which had responded to an alarm at a building materials supply store. Witnesses on the ground said the helicopter was heading northwest when it "started spinning" and "the nose went straight down."

The Officer-in-Charge of the Police Helicopter Unit said that for a call as this, the pilot would push the speed up en route to get there as soon as possible. The altitude en route would be 500 feet above ground level (agl). As the helicopter approached the area, the pilot would descend to approximately 200 feet agl. On arrival, the helicopter would enter a right-hand turning orbit, so that the observer in the right seat could position the bottom-mounted forward looking infrared camera (FLIR) so as to observe parts of the building where a suspect might be, on his monitor. On entering the orbit, the pilot would reduce his airspeed to 50 knots.

At 0007:17, a voice identified as the observer on board Unit 400 exclaimed, "Other way, other way, other way!" Topeka Police Department dispatch responded, "400?" At 0007:21, Unit 400 made an unintelligible call over the radio. This was the last radio transmission from the helicopter (NTSB 3, 2001).

Several witnesses on the ground observed the helicopter as it was orbiting in the area, and when it went down. One witness said that the helicopter was heading "in a northwest direction" when it "started spinning, going down on the ground, over by Lowe's." The witness described the helicopter going down as making three, counter-clockwise descending turns. "I thought they might get it under control, but it was going down pretty quick. After that, I heard a thud" (NTSB 3, 2001).

Another witness said that the bright lights from the helicopter caught her attention. When she noticed, she saw the helicopter spinning. The witness said that it seemed like the helicopter stopped. "It sounded funny ... like it was choking, like it was running out of power. It started going down, and we heard the crash" (NTSB 3, 2001)

NTSB Probable Cause (NTSB 3, 2001)

The pilot's failure to maintain translational lift while maneuvering, and the loss of tail rotor effectiveness. Factors relating to this accident were the tailwind, low airspeed, low rotor rpm, and the pilot's lack of overall experience in helicopters.

Accident Occurred December 3, 2007 near Whittier, Alaska (NTSB 4, 2007)

On December 3, 2007, about 1718 Alaska standard time, a Eurocopter BK117C1 helicopter, N141LG, is presumed to have sustained substantial damage during impact with ocean waters, about 3 miles east of Whittier, Alaska.

The helicopter was based in Soldotna, Alaska, and flew to Cordova to pick up the patient about 1340. After boarding the patient, the helicopter departed for Anchorage about 1640. During the flight from Cordova to Anchorage, the pilot communicated with the hospital's communications center at 10-minute intervals via satellite telephone. The helicopter was reported missing when the pilot failed to make a required position report, and attempts to communicate with him failed.

To date, the only pieces of helicopter wreckage recovered are fragmented pieces of the main rotor blades, and the aft left cabin door (NTSB 4, 2007).