Sikorsky HH-60L Hoist Cable Damage Highlights Need for Cable Guards (N964SB, Santa Barbara County Fire Department)
On 3 December 2022 Sikorsky HH-60L N964SB of the Santa Barbara County Fire Department suffered hoist cable damage while conducting hoist training from Santa Ynez Airport/Kunkle Field, California.
Santa Barbara County Fire Department Sikorsky HH-60L N964SB Hoist Cable Damage (Credit: US Department of the Interior (DOI) & US Forest Service (USFS) SAFECOM aviation safety reporting system)
The Incident
The helicopter was also equipped with a belly-mounted Kawak Aerial Liquid Delivery System (ALDS) firefighting tank system and elongated landing gear. The Department of the Interior (DOI) & US Forest Service (USFS) SAFECOM aviation safety reporting system report states:
…the helicopter slowly approached the deployment location with the Crew Chief seated at the rear door [i.e. the right hand cabin door].
As the rescuer neared the ground, a cable swing developed in which the crew chief determined to be excessive.
The Crew Chief decided to bring the rescuer back up to the helicopter…
As the cable length reduced the swing amplitude consequently increased and…
…the cable swung forward of the aircraft sidestep and wrapped around the backside of the cable guard where two bolt heads were protruding.
Santa Barbara County Fire Department Sikorsky HH-60L N964SB Protruding Bolt Heads (Credit: US Department of the Interior (DOI) & US Forest Service (USFS) SAFECOM aviation safety reporting system)
These screws are reported to have had “sharp edges” and “about 1/4″ of threads showing”. This contact resulted in extensive damage to the hoist cable with 7 of the outer cable strands becoming sheared.
The rescuer made it into the aircraft safely, but the cable was not able to be reeled all the way into the drum. The cable hook was secured to the aircraft’s upper strut tiedown and the aircraft was flown back to base, where the cable was changed, and the aircraft was placed back into service.
Safety Action
Kawak is developing a user-installed kit “that will prevent the deployed cable from coming in contact with any structure on the tank or step.” It will add a “simple but robust bar guard, and will have rub strips along the whole length” and kits and a Service Letter will be distributed to operators free of charge.
New Kawak Extended Cable Guard (Credit: US Department of the Interior (DOI) & US Forest Service (USFS) SAFECOM aviation safety reporting system)
Our Safety Observations
This occurrence highlights the importance of cable guards and considering the credible cable swing arc. The Flight Safety Foundation (FSF) BARSOHO offshore helicopter operations Safety Performance Requirements contains Control 12.4: Hoist Cable Protection:
Hoist cables must be protected from damaging contact with aircraft structure.
UPDATE 30 May 2024: IOGP has issued version 1 of their Recommended Practice 699 Emergency Response Services. 699/5-1 does require hoist cable protection in a table of equipment, which is good. It is however accompanied by footnote 8. Readers will notice there are only 7 footnotes listed below the table and that footnote 5 (not assigned to an item in the table) actually says: If hoist cable protection is not available due to the aircraft type in use this is to be discussed, agreed and documented with the Company Aviation Advisor. This was the only equipment listed in the table that IOGP recommend can be waived by Company Aviation Advisor (something that was unsuccessfully challenged in two rounds of industry comment).
In contrast we contend that if an aircraft is proposed to be used for hoisting and it lacks such protection it is both unsuitable and unsafe. Furthermore, any aviation advisor who waived hoist cable protection would be demonstrating gross negligence.
Safety Resources
The European Safety Promotion Network Rotorcraft (ESPN-R) has a helicopter safety discussion group on LinkedIn. You may also find these Aerossurance articles of interest:
- Swinging Snorkel Sikorsky Smash: Structural Stress Slip-up
- SAR Hoist Cable Snag and Facture, Followed By Release of an Unserviceable Aircraft
- Guarding Against a Hoist Cable Cut
- Fatal Fall From B429 During Helicopter Hoist Training
- TCM’s Fall from SAR AW139 Doorway While Commencing Night Hoist Training
- SAR AW139 Dropped Object: Attachment of New Hook Weight
- Swedish SAR AW139 Damaged in Aborted Take-off Training Exercise
- Military SAR H225M Caracal Double Hoist Fatality Accident
- Fatal Taiwanese Night SAR Hoist Mission (NASC AS365N3 NA-106)
- SAR Crew With High Workload Land Wheels Up on Beach
- NZ Firefighting AS350 Accident: Role Equipment Design Issues
- Fire-Fighting AS350 Hydraulics Accident: Dormant Miswiring
- HESLO EC135 LOC-I & Water Impact: Hook Confusion after Personnel Change
- Maintenance Issues in Fire-Fighting S-61A Accident
- South Korean Fire-Fighting Helicopter Tail Rotor Strike on Fuel Bowser
- Firefighting AW139 Loss of Control and Tree Impact
- Competitive Behaviour’ and a Fire-Fighting Aircraft Stall
- Short Sling Stings Speedy Squirrel: Tail Rotor Strike Fire-Fighting in Réunion
- Black Hawk Scud Running in Tennessee: IIMC & CFIT
Recent Comments