Perimeter

Snorkel hitting rotor blades was likely cause of fatal helicopter crash

Four were killed in the May 25 crash of the FireHawk helicopter at Leesburg, Florida

FireHawk helicopter
File photo of FireHawk helicopter at Boise, April 21, 2017. Photo by Bill Gabbert.

A three-page preliminary report issued by the National Transportation Safety Board said it appears that the violent swinging of a snorkel hose attached to a newly installed water tank caused the crash of a FireHawk helicopter on May 25 at Leesburg, Florida. All four on board were killed. To our knowledge the names of the deceased have not been released.

A snorkel is a large diameter hose attached to a fixed internal or external water tank that usually has a water pump at the lower end of the hose to fill the tank while the helicopter hovers over a water source.

The aircraft, N9FH, was a Sikorsky UH-60A, a Blackhawk registered to Brainerd Helicopters Inc. out of Leesburg, Florida. The police department described the owner as Brainerd Helicopters Inc./Firehawk Helicopters, located at Leesburg International Airport.

The initial information released by the FAA the day after the incident said there was “one flight crew member and three passengers” on the helicopter, but the NTSB report says there was a “pilot, copilot, and two passengers.” The FAA also said the aircraft “lost control of the bucket causing the rotor section to separate”. Obviously is it common for early information about an accident to be erroneous.

Below is the text from the NTSB Preliminary Report.


“According to the operator, a new water tank and snorkel were installed on the helicopter to facilitate firefighting operations in accordance with supplemental type certificate (STC) #SR00933DE on May 17, 2021. Several days of ground testing and calibration were performed before the accident flight, which was the first flight after the STC was installed.

“Witnesses reported that the helicopter made six uneventful passes in front of the operator’s hangar at LEE and dropped water that was picked up from a lake adjacent to the airport. On the seventh pass, an employee of the operator noticed the snorkel swinging. He called the LEE air traffic control tower on the phone and told the controller to ask the pilot of the helicopter to slow down and land immediately. Before the controller could contact the pilot, the helicopter transitioned to forward flight, gaining altitude and airspeed. The employee noticed the snorkel “violently” swinging and he then heard a loud bang, which he believed was the result of the snorkel contacting the main rotor blades or tailboom. He then saw pieces, and then the tail section separating from the helicopter. The helicopter started to spin and fell below the tree line. He heard a loud explosion and saw smoke rise above the tree line.

“According to another witness who worked for the operator, she missed the helicopter’s first pass but watched the remaining six passes. She noted that the water being dropped from the tank was “very dirty.” On the helicopter’s last pass, while it was coming in and slowing down, she noticed the snorkel swing in a large circle and at one point, the snorkel end came very close to the main rotor blades. She immediately started waving her arms at the pilot to try and get his attention, but he did not see her. As the pilot transitioned to forward flight, she ran beside the helicopter and continued to wave her arms. Shortly after the helicopter climbed and gained airspeed, she heard a loud bang and saw multiple main rotor blades separate and hit the tail section. She then saw the tail section fall to the ground and the helicopter enter a flat spin.

“The helicopter was located in heavily wooded, swampy terrain about 1322 ft east of runway 3. The helicopter came to rest slightly inverted on its left side on a heading of 040° magnetic. The tail rotor section was found about 78 ft north of the main wreckage. One half of a rotor blade was found about 600 ft south of the main wreckage and one half of another rotor blade was found about 200 ft west of runway 3. Parts of the newly installed water tank and snorkel assembly were found on the west side edge of runway 3. The water pump housing, which was installed near the snorkel inlet was heavily fragmented. The stainless-steel snorkel suction cage was located about 50 ft west of runway 3 and collocated with a section of main rotor blade. There were several pieces of fairings and lightweight material lodged in the top of trees along the flight path from the edge of the tree line to the main wreckage.

“The landing gear, main rotor system, main rotor drive system, engine, hydraulic system, and the forward portion of the tail rotor drive system were thermally damaged by the postcrash fire. The majority of the cockpit, cabin, and flight controls were consumed by the postcrash fire.”

Thanks and a tip of the hat go out to Bob.

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3 thoughts on “Snorkel hitting rotor blades was likely cause of fatal helicopter crash”

  1. This was a sad accident. We don’t know what may have been different with this aircraft or its operation, hopefully they will figure it out.

    With all caution required, one advantage of operating helicopters in a public agency is that issues such as snorkles that exhibit undesired flight characteristics can be altered in terms of length, adding weight or even by adding small fins to change their wayward tendencies. There is no formula for this, only empiracle observation and using what works. Of course this is not easily possible for FAA approved (STCed) installations, without further approval. A belly mounted camera for the pilot to easily see their snorkle head are not a bad idea.

    I have seen the addition of small fins that actually cup a little air in forward flight dramatically change snorkle head flight characteristics. I think in light of this accident, companies like Simplex and Kawak who are in the tank business should put a bit of R &D effort into this phenomenon. I know snorkles have punctured chin bubbles and hit engine cowls but this is the first time I’ve heard of a snorkle swing causing such a tragic outcome.

  2. There is NO DIFFERENCE between Public Agency and private operators when it comes to safety of flight. Asserting otherwise is intellectually dishonest. When an issue like this arises, the fix, as arcane as it may be is the same. The problem does not care about the aircraft ownership class. The process of identifying the problem and correcting it does not change because it is privately held VS a public airframe. Suggesting that it is simpler to be a public airframe is poppycock. Problems with circular airflow around helicopters has caused lots of hair pulling for years, and it’s truly sad this continues, but the method of ownership of the airframe has no influence on the actual physics involved.,.

    1. Did I not say ” with all caution required”? Do you believe that implies something different than simply not having an FAA person say it is approved? If you think the level of safety is the same we should ground all single engine hoist operators, make all public use agencies get 133 and 137 certificates. Ambulances exceed the speed limits all the time, perhaps we should get them to slow down. It is very easy to throw down the safety card and make it sound like I was suggesting some path that was ignorant or careless but any of the things I’ve suggested have been done safely, with positive results and are in use today.

      The modern day FAA sometimes says no to modifications because they lack time or expertise to evaluate them and they certainly can take eons for an approval. Many public agencies not only keep doing their good work but do it more effectively on occasion, because they can do their own research, test flights and training, on their own schedule.

      My purpose for posting was to bring up the issue of snorkles deviating from a true flight path as not being something new and that may be addressed with proper design and proper testing. Standards ARE standards but successfuly completed modifications aren’t necessarily better with FAA approval. A case on point is that for years many non type certificated Huey operators have flown with their snorkle stowed with a latching hook so they didn’t have to hook up hudraylic or electric lines when they get to a fire or take up space in the cabin with a rather large piece of equipment. They all do it a bit differently and none of it was FAA approved because the FAA has no oversight of non typed airframes or equipment.

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