The owner of the Robinson R44 II helicopter reported that, five days before the accident, he had flown the helicopter for about an hour at an altitude of 1,000 feet mean sea level when the engine lost total power. He located a field for landing and performed an autorotation to the ground. The helicopter was not damaged during the landing.
The owner further stated that he restarted the engine and that it ran at idle for several minutes before he pulled on the collective and the engine lost power again. The owner restarted the engine and kept the main rotor disengaged while he ran the engine up to 100% power without a load. He said the engine ran well but that, when he engaged the main rotor and started to pull on the collective, the engine lost power another time.
The owner shut down the engine and contacted the helicopter manufacturer about repairing the helicopter.
An FAA inspector contacted the pilot on the morning of the accident and told him that work on the helicopter was being performed by two mechanics from Florida Suncoast Helicopters. According to the FAA inspector, he observed the mechanics as they performed maintenance on the helicopter in the field where the helicopter had previously landed. The mechanics told the inspector that they had cleaned the fuel screen and looked for contamination.
A pilot employed by Florida Suncoast Helicopters then started the engine and let it warm up. The pilot subsequently pulled on the collective, and the engine lost total power.
After discussion with the helicopter manufacturer, the mechanics replaced the fuel servo unit with a new one. The FAA inspector then departed and asked the mechanics to call after the repairs were complete, and to tell him what was repaired.
According to the mechanics and the pilot employed by Florida Suncoast Helicopters, after the fuel servo unit was changed, the pilot performed a test run of the engine and hovered the helicopter for several minutes. No problems were noted. The pilot and one of the mechanics boarded the helicopter and departed the field about 1401 with the intent of repositioning the helicopter to Sarasota/Bradenton International Airport (KSRQ), where the company’s maintenance facility was located.
About 15 minutes later, the engine lost total power, and the pilot performed an autorotation to a road near Tampa, Florida.
After touchdown on the road, the helicopter slid on the pavement due to its forward momentum. The helicopter then slid sideways, and the main rotor blades hit a telephone pole, and a 2.5-ft-long piece of a main rotor blade separated and hit the windshield of a truck driving on the road. A passenger in the truck was killed, while the driver passenger in a nearby vehicle was fatally injured, and the driver sustained serious injuries.
The helicopter came to rest along a heading of 180 next to a telephone pole that had been cut in half. Both main rotor blades were fractured at the tips and had cable cuts along the blades. The skids on the helicopter were damaged, consistent with a hard landing, and the skids’ rear cross-tube was fractured. The tailcone was buckled on the top located at the second bay. One pitch link for the rotor blade had fractured and separated. The vertical firewall was wrinkled at the lower right corner.
Examination of the engine revealed that the induction air inlet duct was partially collapsed. The inner rubberized fabric liner of the duct had partially delaminated and separated from the outer rubberized fabric, obstructing the interior volume of the duct. The wire stiffener between the two layers of fabric was displaced in two locations near the center of the duct length, at the 90° bend.
The induction air inlet duct was provided to the National Transportation Safety Board’s Materials Laboratory for further investigation. The duct was dissected to examine the internal surfaces. A liquid residue was observed in some areas of the duct. The residue was analyzed, and the best matches were several oxidized vegetable oils, including castor oil, which was used by the duct manufacturer, along with a water-based release agent, in the assembly and curing of the air inlet duct.
Probable Cause: Contamination of and an inadequate bond between the two layers of fabric comprising the helicopter engine’s air induction inlet duct, which resulted a partial collapse of the duct, obstruction of the airflow into the engine, and a total loss of engine power.
As with most things in life, “hindsight is 20/20”. From the initial power loss and the strange behavior of the engine quitting once the blades were engaged, etc., why not trailer the aircraft to an adequate facility where a thorough and proper examination of all components can be examined? Pressure to “fix and fly” here led to “hanging parts” and missing the true problem cause.
This April 2019 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
This is what happens when mechanics replace components without knowing what exactly is wrong with it, which in this cause that was nothing wrong with it. It’s always been referred to as as “shot gunning”.
On the other hand, sophisticated components usually require return to the manufacturer to determine issues. In this case coincidence played a role when it appeared they corrected the problem.
Lacking a well defined solution and given the path for fly away, it should have been trailered.
Agree with the trailering. Could have been done so easy. Where was the FAA during all this decision making.
I read accident reports so I can make better decisions in the future.
The owner/operator, in this case the same, is responsible for the final decision to fly.
Sad to say this, but here come the lawyers.
First, I am not an A&P. Several years in auto mechanics. Before I even finished reading this story I was wondering why the Mechanics were so focused on fuel when the engine ran at full static power. The mechanics were just changing parts in an attempt to get lucky. I don’t know the Tampa area but since the helicopter was being flown for more troubleshooting, should this flight been done with a special ferry permit?
As far as the induction hose, many times these type of hoses collapse on the inside, not being obvious from the outside. I have seen this on water hoses and radiator hoses.
I would question the mechanics and the the company’s records on this one.
Didn’t the mechanics and PILOT ” see ” the condition of the air induction hoses?
It seems like an inspection of same would be standard procedure.