I just found the original thread.....
JetRanger III and a Bell 412 water-bombing in fire fighting operations near Bendora Dam, sw of Canberra.
Bell 412 pilot noted absence of JetRanger during a racetrack pattern, tried to contact him and then saw it upturned in the water. He broadcast a PAN call, released his water bucket, and hovered close to the upturned helicopter. Crewman entered the water and freed the unconscious pilot from the wreckage. There were no known witnesses to the accident.
The JetRanger was substantially damaged. Examination indicated impact with the water in a slightly right side down, nose-low attitude, that both rotors had been under power on impact, and the engine was probably producing above flight idle power at that time. No evidence of any pre-impact engine or other aircraft abnormality.
Impact damage to the pilot's helmet was consistent with it being struck either by the door frame structure or a main rotor blade.
An estimated 135 L (107 kg) of fuel on board, sufficient for planned flight, free from contamination and of correct type.
Bucket attached to JetRanger's cargo hook by 24 m steel cable. Both release mechanisms operated normally during subsequent testing.
An internal `cinching strap' controlled the volume of an `as-manufactured' `Bambi Bucket' via a series of metal `D' rings positioned along the length of the strap. That allowed selection of 70%, 80% or 90% of bucket capacity. Nylon webbing loops stitched to the inside of the collapsible synthetic bucket positioned the strap inside the bucket. The bucket strap fitted to the occurrence bucket was non-standard and did not include any `D' rings. Instead, the strap had been tied off with a knot. That was contrary to the bucket manufacturer's Repair Assessment Manual1 that stated that it was not an acceptable practice to tie knots on the strap. The manufacturer cautioned that such actions may result in a false indication of the actual maximum volume of water in the bucket. It was determined that the bucket was of a non-standard construction.
Post accident testing of the bucket's electric water release mechanism revealed that the bucket's mechanism operated normally.
The JetRanger pilot held a CPL(H), 6,713 hours total with in excess of 2,917 hours on type, appropriately endorsed for, and very experienced in, fire fighting and long-line operations.
The pilot sustained traumatic head injuries and was submerged for an undetermined period. During subsequent interviews he was unable to recall any details of the accident.
The AUW for the helicopter, including 420 L of water, estimated to be about 3,309 lbs. The MTAUW was estimated to be about 3,320 lbs. The helicopter's centre of gravity was estimated to have been within limits.
Met forecast indicated east-northeasterly wind at 15 kts. Other pilots reported winds varied in direction and strength. Visibility was 'good', with some smoke in the area. The investigation was unable to determine the actual wind direction and speed at the time of the accident.
FAA Advisory Circular AC90-95 described the conditions under which a loss of tail rotor effectiveness (LTE) can occur. Included among those conditions were: high all up weight; out of ground effect hover; low forward airspeed; high power settings; and a wind direction from the left or rear of the helicopter. LTE can result in a loss of control.
Other pilots reported that the JetRanger pilot had been lowering the bucket vertically into the water to fill from an out of ground effect (OGE) hover, and then lifting it clear vertically before transitioning to forward flight. Underwater photographs of the helicopter showed that the bucket cable was not positioned over the rear of the skid assembly. Examination of the helicopter's landing gear skids did not reveal any damage from the bucket cable.
Civil Aviation Order (CAO), 20.11, 5.1.1(a), stated that:
Aircraft shall be equipped with one life jacket for each occupant when the aircraft is over water at a distance from land:
(a) in the case of a single engine aircraft - greater that that which would allow the aircraft to reach land with the engine inoperative...'
Para 5.1.7 of the CAO stated, in part:
`Where life jackets are required to be carried in accordance with subparagraph 5.1.1(a) each occupant shall wear a life jacket during flight over water...'
The pilot was reported to have been conducting his water pick-ups from close to the shoreline of the dam. The pilot was not wearing a personal flotation device (PFD).
A
Flight Safety Foundation report - External Loads, Powerplant Problems And Obstacles Challenge Pilots During Aerial Fire Fighting Operations, based on USA accident reports from 1974 to 1998, stated in part:
`Research has shown that the average person, when immersed in cold water, can hold [their] breath for 17.2 seconds, plus or minus 3.7 seconds. Studies of water accidents involving military helicopters and civilian helicopters, however, show that successful underwater escape requires 40 seconds to 60 seconds'.
The pilot had not undertaken HUET.
ANALYSIS The pilot was qualified and authorised and had recent experience for the operation.
Sufficient fuel of the correct type on board for the flight. Rotational damage to the main rotor system and engine was consistent with engine operation at the time of impact.
The helicopter was at high all up weight and operating close to maximum predicted performance in an area with reported variable winds. While those conditions would have increased the risk of encountering LTE, the pilot was highly experienced in long-line and water-bombing operations and had been operating in the area of Bendora Dam for most of the day. That experience should have mitigated the risk that LTE was a factor in this occurrence.
Although of a non-standard construction, the occurrence bucket was assessed as being capable of normal operation, and was able to be carried by the helicopter at its post-accident assessed capacity. There was no evidence that it contributed to the accident.
While the manufacturer of the 'Bambi Bucket' warns of the possibility of dynamic rollover when conducting water-bombing operations, the use of a 24m long-line by the pilot, and vertical water pick-up would have diminished the likelihood for that to have occurred in this occurrence.
The investigation could not confirm the position of the cargo hook release circuit breaker prior to the accident. Had the circuit breaker been in the open-circuit position the rapid release of the bucket by the pilot, such as in an emergency situation requiring jettison of the load, would not have been possible.
The nature of the helicopter's impact with the water, and the resulting damage sustained by the pilot's helmet, reinforced the protective benefits of the use of flightcrew helmets.
It is possible that, during the water pick-up, the pilot may have been at a distance from the shoreline from which, had an engine failure occurred, the helicopter would not have been able to reach land. In that case, the provisions of CAO 20.11 would have applied, requiring the pilot to wear a PFD. That would have greatly eased the difficulty experienced by the helicopter crewman and others performing the rescue and, potentially, lessened the severity of the pilot's injuries.
Given the absence of pilot recollection and witness reports of the accident, and the lack of detailed indications of operation of the helicopter at impact, the reason(s) for the accident could not be established.
While recognising that, in this accident, the pilot was rendered unconscious and therefore unable to exit the helicopter without assistance, the ATSB draws attention to the benefits of HUET. Studies have shown that escape from helicopters involved in water accidents can take longer than the average time that a person can hold their breath. HUET has been shown to decrease exit times from an immersed helicopter, and increase the likelihood of a successful exit by an uninjured occupant. The provision of HUET to pilots, aircrew and passengers regularly operating over significant expanses of water would maximise the possibility for the successful exit of occupants from an immersed helicopter.
SAFETY ACTION
Local safety action
The operator has amended the company's operations manual to correctly reflect the types of fire buckets used on the company's individual helicopter types.
The operator has standardised the position of the external load jettison switch on the different helicopter types used by the company in fire fighting operations.
The company's operations manual now details the type of safety clothing to be worn by pilots when engaged in water-bombing operations in company helicopters. The clothing specified includes the wearing of cotton or better, flying suits, approved helmets and comfortable fitting life jackets. Inflatable life jackets have been positioned in each helicopter for that purpose.
The operator has introduced a system for tracking the fitment and maintenance history of cargo hooks fitted to company helicopters.
ATSB safety action In a briefing to the Civil Aviation Safety Authority, the ATSB drew attention to the fact that the occurrence bucket was not of standard manufacture, and highlighted the possible effects of the use of non-standard buckets by helicopters during fire fighting operations.
As a result of this occurrence, the Australian Transport Safety Bureau issues the following safety recommendations:
Recommendation R20030219
The Australian Transport Safety Bureau recommends that the Civil Aviation Safety Authority, in conjunction with the relevant industry associations, highlight the safety benefits to helicopter pilots and crew of the wearing of personal protective equipment, such as helmets and personal flotation devices when carrying out water-bombing in support of fire fighting operations, through safety promotion initiatives.
Recommendation R20030220
The Australian Transport Safety Bureau recommends that the Civil Aviation Safety Authority, in conjunction with the relevant industry associations, assess the desirability of a requirement for Helicopter Underwater Escape Training for specialist aerial work operations, such as water-bombing in support of fire fighting operations.
Recommendation R20030221
The Australian Transport Safety Bureau recommends that the Civil Aviation Safety Authority, in conjunction with the relevant industry associations, consider advising Australian helicopter operators involved in water-bombing in support of fire fighting operations, of the need to review the type of fire-buckets used to ensure that they comply with the bucket manufacturer's guidance for use on helicopter types and to ensure that the fire-buckets are appropriately maintained.
(Sorry for any confusion. I started a new thread before I found this original thread, deleted it and reposted here.
ATSB report.)
Interesting issues.
Thanks, Time Out
Heliport