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N1090S accident description

Hawaii map... Hawaii list
Crash location Unknown
Nearest city Hauula, HI
21.614135°N, 157.914473°W
Tail number N1090S
Accident date 21 Jul 1995
Aircraft type Mcdonnell Douglas 369D
Additional details: None

NTSB Factual Report


On July 21, 1995, about 1227 hours Hawaiian standard time, a McDonnell Douglas 369D, N1090S, operating under call sign Air 1 by the Honolulu Fire Department (HFD) as a public use aircraft, was destroyed while maneuvering near Hauula, on the island of Oahu, Hawaii. Changing meteorological conditions existed during this time. The pilot and two passengers, who were suspended beneath the helicopter in a rescue net, received fatal injuries. The flight originated on the day of the accident as an on-going search for a lost hiker in the Koolau Mountains near Sacred Falls.

The pilot had made two prior insertions of search and rescue (SAR) personnel into the general area of the search. They repelled out of the helicopter to the ground. On each of the two insertions an observer was onboard to retrieve the rope.

The first two inserted SAR personnel were subsequently relocated separately by the pilot with an observer onboard to a campsite with the use of a Billy Pugh helicopter rescue net. According to an HFD report to the Safety Board, after returning to the staging area, a decision was made to insert two Honolulu Police Department (HPD) officers into the search area at one time using the Billy Pugh net. The report stated that the decision was made by the pilot to fly without an observer.

According to an HFD pilot, when operating without an observer the pilot must lean outside of the helicopter to maintain visual contact with the net.

According to resident search personnel, changing trade winds and cloud cover are a common phenomena in the area and had been affecting the search for 5 days. After the pilot departed the staging area with the two HPD searchers in the net, a previously placed searcher radioed the pilot of Air 1 three times. He advised the pilot, "Pete, it's just too soupy up here, your gonna have to take em back down. I cant even see the other side of the river." A review of the recorded voice communications revealed that there was no verbal acknowledgment from the pilot. Shortly thereafter, a searcher heard a crash or impact sound followed briefly by a sound of the helicopter engine noise spooling up then down and then silence.

Two people were hiking together in the Sacred Falls area at the time of the accident. They were both interviewed by telephone. Both hikers observed the helicopter in-flight with the net attached; however, they could not positively identify what was in the net. The time frame of between 1225 and 1230 was established by their need to start hiking back out of the canyon by a certain time.

The first hiker to be interviewed stated that she observed the helicopter turning slowly and descending with the net swinging back and forth like a pendulum. She estimated the amount of swing to be about 20 to 30 degrees. She also noted that the helicopter was close to the mountainous terrain and the weather was cloudy with intermittent light rain.

The second hiker also observed the helicopter turning slowly, but noted that the helicopter was partially in the clouds which were boiling around the helicopter. He stated that the net was in the clear, but swinging back and forth an estimated 45 to 50 degrees like a pendulum. He also noted that the helicopter appeared to be close to the mountainous terrain.


The pilot was employed by the HFD on March 1, 1991, as a fire fighter. On October 13, 1994, the pilot met all the qualifications for flying as a relief pilot. The pilot was selected for relief pilot training on January 13, 1994. The HFD does not have a relief pilot position. Once the firefighter is qualified to be a relief pilot, he continues in his regular position as a firefighter and is temporarily assigned to a pilot's position in the event of an absence of the regular pilot.

At the time of the request, he reported a total of 1,990 fixed wing hours and 321 helicopter hours, for a combined total flight time of 2,311 hours. Examination of all available records disclosed differences in the pilot's flight experience as entered in the various documents.

The pilot reported a total flight time of 3,400 hours with 200 in the last 6 months on his last class two flight physical, dated June 8, 1995.

According to helicopter flight school records, the pilot started helicopter flight training on September 11, 1992, at Burbank, California. The operator provided a Bell 47-D1, with a flight instructor.

According to the operator and flight instructor records, the pilot flew from September 11, 1992, through October 9, 1992, during which time he received his private, commercial, and CFI add-on ratings. The instructor stated that he flew 34.8 hours of dual flight instruction with the pilot. The instructor also stated that the pilot flew an additional 17 hours of solo while preparing for his add-on ratings. The pilot's last add-on rating was for flight instructor rotorcraft helicopter on October 9, 1992. At that time, he reported 57 total helicopter flight hours, with 22 hours of dual instruction and 38 hours of solo flight. The pilot's log book documents 22.8 hours of dual and 39.4 hours of solo flight in the Bell 47-D1 helicopter.

According to the pilot's log book, on February 13, 1993, the pilot took his first dual flight instruction in an HFD helicopter. According to HFD records, at the time of the accident the pilot had accumulated a total of 222.2 hours in the HFD helicopter; 50.3 of these hours were dual instruction. The last documented dual instruction was October 13, 1994, and consisted of his relief pilot checkout flight and a biennial flight review.

According to a pilot history form provided by the pilot to HFD, as of June 20, 1995, the pilot reported 3,011 total flight hours. Of that, 511 hours were helicopter flight hours with about 200 hours in a MD369D. In the last 90 days he listed 3 hours of MD369D helicopter flight time. A review of the pilot's actual flight logs revealed that they were sporadically dated with incomplete entries and no page totals.

An interview was conducted with the HFD chief pilot. The chief pilot stated that their were no written training records, written examinations, or dual flight instruction formats given the accident pilot.

An examination of the mission log book revealed that the accident pilot responded to about 33 alarms as a solo pilot. During the 33 alarms, the pilot performed about 10 rescues, with about nine water or net operations, and three repellings.

The chief pilot was asked if their was any evidence of an emergency briefing of the HPD net passengers prior to the last flight. He stated that there was no briefing. He was then asked if there would have routinely been a briefing of passengers prior to flight. He stated no because they routinely work with their own personnel who are trained by the HFD.


The accident helicopter was operating as Air 1. To differentiate between the two helicopters on the ground for maintenance purposes or general reference, the accident helicopter was actually known as Air 2. Whichever helicopter was airborne, for communication purposes, the helicopter was called Air 1. If the second helicopter was called out at the same time, it was called Air 2.

The McDonnell Douglas 369D helicopter was manufactured as a 1980 model. According to the maintenance records, at the time of the accident the helicopter had accumulated 6,592.6 hours of operation. The helicopter was maintained under a maintenance program provided by the manufacturer, McDonnell Douglas, as a 100, 200, and 300-hour inspection program. A review of the records revealed no outstanding maintenance items.

During conversations with the accident pilot's wife, she stated that her husband had told her that both helicopters had vibrations. She stated that Air 2 had an overtemp problem some time around July 1, 1995. She stated that her husband said several attempts were made to fix the problem, but he finally fixed it himself.

A review of the discrepancy sheet revealed that on July 13,1995, the engine was reported to be running hot. The engine was subsequently replaced along with a turbine outlet temperature gauge, and a gasket was installed to seal up the heater plate in the scavenge air system.

The HFD personnel were questioned regarding high or over temperature problems relating to the accident pilot. They reported that the pilot had overtemped (operational exceedence) both helicopters. On February 26, 1995, the pilot had a start temperature exceedence (hot start) in helicopter N58388. On March 9, 1995, the pilot experienced an operational temperature exceedence in the accident helicopter. The engines were inspected in accordance with the Allison 250-C20 series operations and maintenance manual table III-8, special inspections.

The helicopter rescue net is manufactured under an FAA supplemental type certificate (STC) and is designed for two 180-pound persons. There are no operating limitations provided with the STC. According to the manufacturer, the net was designed for rescue recovery; however, it can also be used for personnel transfer. The net is carried by one 9/16-inch by 50-foot 8-strand plimoor Columbian rope. The maximum yield strength is 9,000 pounds. The rope hooks to the helicopter from the center of the belly by two solenoid operated hooks/latches. The single rope is hooked to each hook by a separate Carabineer. Except for a water bucket operation, power to the hooks is disconnected by pulling the circuit breakers and disarming the switch to prevent inadvertent release of the load.


The accident site was located in the Koolau mountain range at an elevation of about 2,000 feet msl. The terrain slope was estimated to be about 60 to 70 degrees. The wreckage was co-mingled with a dense foliage growth averaging about 6 feet deep.

Postaccident examination of the wreckage started during the helicopter sling load retrieval process. The left skid was inadvertently dropped into a canyon during the sling load operation and not recovered.

The Billy Pugh helicopter rescue net that had been occupied by the two HPD officers was found about 150 feet upslope from the main wreckage. The lift rope attach points for the net were missing. The rectangular tube frame was bent down in the front about 9 inches. The lead weight drogue chute ring was found bent over 180 degrees and still attached to the rescue net by it's rope.

The net rope was found wrapped around the rotor mast at the rubber boot. Examination of the rope revealed paint transfers of different colors similar to the coded pitch change and rotor blade component colors. The rope was removed and measured. The recovered rope was measured to be 44-feet 8-inches in length. According to an HFD pilot, the rope being used was 50 feet in length.

The red coded main rotor blade separated from the main rotor system and had approximately a 140-degree downward bend, about 28 inches outboard of the blade root end. The abrasion strip evidenced a material transfer of fiberglass from an unknown source. The upper and lower trailing edges of the blade were spread open from the blade tip inboard approximately 89 inches, and had rope marks on the blade bottom and inside of the upper trailing edge. The blade had negligible leading edge damage and the tip weight was intact.

The green coded main rotor blade separated from the main rotor system and had approximately a 30-degree bend rearward at midspan with no leading edge damage. The pitch case remained attached to the blade and had a fracture of the top side. The forward leading edge lead/lag pin was found missing. Impact damage was found near the pins normal position. The blade exhibited substantial damage, but was intact for the full length. The blade tip weight was intact.

The yellow main rotor blade separated from the main rotor hub assembly. The outboard 54 inches had an overload fracture and separation in the form of downward bending. There was no leading edge damage on the outboard 54-inch section of the blade. The blade tip weight was intact.

The blue coded main rotor blade separated from the main rotor system and had approximately a 4-foot inboard-to-outboard tear in the top side blade skin, with corresponding airframe yellow paint transfer for the entire length of the tear. The blue blade also had an approximate 64-degree downward bend of the outboard 2 feet. The blade had leading edge indentations on the outboard 3 feet of the blade. The pitch case and blade root were separated from the blade and not recovered.

The white coded main rotor blade pitch case and approximately 1 foot of the blade root end remained attached to the main rotor hub. An approximate 50-inch section of the inboard white main rotor blade leading edge spar was wrapped around the main rotor mast. The main rotor strap assembly had buckling and stretching, but no complete fracture of the laminates. The blade exhibited leading edge damage on the outboard section of the blade, as well as black paint transfer on the top side of the leading edge abrasion strip. Orange color material similar to the net nylon rope support structure was present in the leading edge indentations.

From the main wreckage northward about 250 feet and separated by a ravine, the majority of the tail boom assembly was found with all components still attached. The tail rotor blades were damaged.

Examination of the longitudinal and the lateral trim actuators revealed that both had been destroyed by impact forces. The trim switch was destroyed by the postcrash fire damage.

Examination of the engine revealed: severe foreign object damage (fod) of the first stage blades and inlet guide vanes; minor fod was found on stage two and three blades; metal particles were found in the combustion area; aluminum deposits were present on the nozzle shield of the first stage; the No. 1 and No. 2 shafts were found intact; the combustion liner was intact; moderate carboning of the fuel nozzles were noted; and there was no distress noted in the gears and the bearings of the gear box.


The closest official weather reporting facility is located about 20 miles away.

A HPD helicopter pilot arrived in the area about 45 minutes after the accident. He reported: the ceiling was 3,500-foot overcast; visibility into the valley above 2,000 feet msl was less than 2/5 of a mile in instrument meteorological conditions; winds at 1,840 feet msl were 20 to 25 knots over an arc of 030 to 060 degrees; and the clouds were drifting in and out of the valley with approximately 10 to 15 minute intervals. While flying over the crash site searching for survivors, he experienced swirling winds in and above a waterfall, with up and down drafts coming over the ridges and fingers of the immediate area. The witness pilot reported that while trying to hover over the crash site, he had experienced conditions conducive to settling with power on several occasions.

There was an advisory to airmen (airmet) in effect for moderate turbulence below 6,000 feet msl.


On July 23, 1995, the Honolulu County Medical Examiner performed an autopsy on the pilot. The cause of death was attributed to multiple blunt force trauma. During the course of the autopsy, no preexisting medical conditions were noted that would have affected the pilot's ability to pilot an aircraft.

During the autopsy, samples were obtained for toxicological analysis by the FAA Civil Aeromedical Institute in Oklahoma City, Oklahoma. The results of the analysis was negative for drugs and ethanol.


On July 23, 1995, a postaccident examination of the recovered helicopter structure, systems, components, and engine was started. The total control continuity was not established due to the fire damage.

The green coded main rotor blade attaching pin was not recovered. A service difficulty (SDR) report search was conducted. There were seven SDR reports of attaching pin bushing, cracking, or safety latch problems, but there were no reported pin losses during fli

NTSB Probable Cause

the pilot's poor judgement by intentionally flying into adverse weather conditions in mountainous terrain with an external load and no observer which resulted in loss of aircraft control. Factors were pressure from the conditions/events and a lack of total experience in the type of operation.

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