Accident Sikorsky UH-60A Black Hawk N9FH, 25 May 2021
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ASN Wikibase Occurrence # 263086
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Type:Silhouette image of generic H60 model; specific model in this crash may look slightly different    
Sikorsky UH-60A Black Hawk
Owner/operator:Brainerd Helicopters Inc
Registration: N9FH
MSN: 70219
Fatalities:Fatalities: 4 / Occupants: 4
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:Leesburg International Airport (LEE/KLEE), Leesburg, FL -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Departure airport:Leesburg International Airport (LEE/KLEE), FL
Destination airport:Leesburg International Airport (LEE/KLEE), FL
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
On May 25, 2021, about 1747 eastern daylight time, a BHI H60 Helicopters LLC, UH-60A, N9FH, was destroyed when it was involved in an accident near Leesburg International Airport (LEE), Leesburg, Florida. The pilot, copilot, and two crewmembers were fatally injured. The helicopter was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 post-maintenance test flight.

According to the operator, a new water tank and snorkel were installed on the helicopter to facilitate firefighting operations. Several days of ground testing and calibration were performed before the accident flight, which was the first flight after the water tank was installed. The purpose of the local flight was to check the operation of the fire tank system. The helicopter made six uneventful passes in front of the operator’s hangar at the airport and dropped water that was picked up from a lake adjacent to the airport. During each of these passes, the snorkel was observed to be stable. However, during the seventh pass, the snorkel was swinging from the helicopter. The helicopter then began to hover, released the water from the fire tank, and transitioned to forward flight, gaining altitude and airspeed. The snorkel continued to make large and slightly erratic oscillations as the helicopter climbed. Afterward, witnesses heard a loud bang, pieces of the main rotor blade and tail section separated, and the helicopter descended vertically to the ground. A postimpact fire ensued.

Given the sudden change in behavior of the snorkel from a consistently stable condition in normal flight to one with large and erratic oscillations, it is likely that the tank snorkel support structure was compromised and allowed the snorkel’s oscillations to increase in such a way that the pump assembly at the end of the snorkel hose contacted the main rotor blade. The contact imparted enough energy to fracture the rotor blade at the contact point, which resulted in an imbalanced rotor system and a subsequent in-flight breakup of the helicopter.

The supplemental type certificate (STC) application for the water tank and snorkel had been approved by the Federal Aviation Administration (FAA) about 1 year prior to the accident. A review of the STC application documentation revealed that the FAA had not classified the water tank and snorkel system as an external load. The structural analysis of the tank used the incorrect weight of the snorkel hose and pump combination and did not account for operational loads that would be imparted into the tank by the snorkel as called for in the certification basis in the project-specific certification plan (PSCP). Testing of the snorkel and pump loads did not incorporate the water tank structure to which the snorkel was attached. The system safety analysis did not address the hazard of the snorkel contacting the main rotor system. Increased consideration in any of these areas could likely have identified design insufficiencies.

In addition, the production tank that was used during flight testing was examined after the accident. A manual load test was performed with the snorkel attached to the tank snorkel support structure. When the snorkel was pulled manually from the tank, the tank structure between the hose coupler and the tank face deformed between 0.03 and 0.05 inches. These manual loads represented only a small fraction of the loads that the tank snorkel support structure would experience during normal operation. Thus, the documentation that supported the FAA’s approval of the STC was insufficient because it failed to consider the failure scenario that occurred during the accident.

Probable Cause: The failure of the water tank snorkel support structure, which allowed the snorkel to contact the main rotor blades. Contributing to the accident was insufficient Federal Aviation Administration oversight of the supplemental type certificate process for the water tank and snorkel.


NTSB (photo)

Accident investigation:
Investigating agency: NTSB
Status: Investigation completed
Download report: Final report



Photo: N9FH departing the accident flight, note swinging snorkel

Photo: Aerial view of wreckage.

Photo: Main wreckage.

Photo: Main wreckage (all photos via NTSB)

Revision history:

26-May-2021 00:00 Captain Adam Added
26-May-2021 00:13 Captain Adam Updated [Aircraft type, Registration, Cn, Operator, Total occupants, Departure airport, Destination airport, Source]
26-May-2021 04:47 RobertMB Updated [Time, Cn, Total fatalities, Other fatalities, Nature, Source, Narrative]
26-May-2021 05:47 Aerossurance Updated [Phase, Source, Narrative]
26-May-2021 05:52 Aerossurance Updated [Location, Source, Narrative]
26-May-2021 07:58 Aerossurance Updated [Embed code, Narrative]
26-May-2021 09:21 A.J.Scholten Updated [Embed code, Narrative]
26-May-2021 10:05 RobertMB Updated [Narrative]
26-May-2021 13:55 harro Updated [Narrative]
26-May-2021 18:42 Aerossurance Updated [Location, Narrative]
26-May-2021 22:26 Aerossurance Updated [Source, Embed code]
29-May-2021 12:51 Aerossurance Updated [Source, Embed code]
20-Apr-2023 01:07 Captain Adam Updated [Time, Location, Nature, Source, Embed code, Narrative, Category, Accident report, Photo]
20-Apr-2023 01:07 Captain Adam Updated [Photo]
20-Apr-2023 01:08 Captain Adam Updated [Photo]
20-Apr-2023 01:08 Captain Adam Updated [Photo]
22-Apr-2023 13:05 Aerossurance Updated [Aircraft type]
22-Apr-2023 14:05 Aerossurance Updated [Source, Embed code]
22-Apr-2023 14:21 Aerossurance Updated [Embed code]

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