EMMETT, ID, USA
N5161E
Hughes 269A
The instructor and the student pilot departed on a training flight with the intention of practicing off airport landings. The instructor maneuvered the helicopter towards a plateau with cliffs on three of its sides, and initiated a demonstration of a pinnacle landing. He then noticed the development of an excessive sink rate and wind change and attempted to correct with collective and throttle. Shortly thereafter, he reached the stop on the throttle and the RPM began decaying. The instructor lowered collective and the rotorcraft impacted the ground hard bouncing back into the air 10-12 feet before striking the ground a second time, during which the tail rotor impacted the ground. Directional control was lost and the rotorcraft rolled over the edge of the plateau and down a steeply sloped embankment. The instructor pilot had logged only 3 hours of flight time, all in the accident aircraft make within the previous 90 days. A weather observation recorded at the Caldwell airport 11 nm south of the accident site reported winds from 110 degrees at 9 knots with gusts to 14 knots. The instructor pilot reported that there was no mechanical malfunction with the rotorcraft during the flight.
HISTORY OF FLIGHT On April 10, 1998, approximately 1630 mountain daylight time, a Hughes 269A helicopter, N5161E, registered to and operated by a student pilot, accompanied by a flight instructor, was destroyed when it crashed approximately five miles southeast of Emmett, Idaho. The student pilot sustained fatal injuries and the flight instructor was seriously injured. Visual meteorological conditions prevailed and no flight plan had been filed. The flight, which was instructional, was to have been operated under 14CFR91, and departed from the Nampa airport, Nampa, Idaho, sometime after 1600. The instructor pilot (IP) reported that he and the student pilot (SP) departed towards Emmett airport with the intention of "practicing off airport landings in the foothills south of the Emmett valley." Approaching a "finger" of a plateau with cliffs on three of its sides the IP proceeded to "demonstrate the procedures to complete an off airport landing." He reported that "there was absolutely no sign of any definitive wind direction on the ground" and subsequently chose a terrain approach route from the south. The IP further reported that "approximately 60 feet AGL (above ground) I noticed 2 things. One was that we were developing a(n) excessive sink rate which I believe was due to a downdraft and two, that there was a wind coming from the west or our left. I immediately turned the helicopter into the wind and applied collective and throttle. While doing so the throttle reached it(s) stop. Ron said "RPM" and I saw that the RPM was decaying, so I immediately lowered the collective as I was out of throttle. This increased our descent rate and I realized we were going to hit the ground fairly hard. We hit the ground so hard that we bounced back into the air approximately 10-12 feet through a combination of the landing gear spring back and ground effect." He concluded reporting that "at that time I attempted to maintain control of the aircraft, but the RPM was still low and the tail rotor hit the ground. This disabled the tail rotor and the aircraft started to spin out of control. Seconds later we spun over the edge of the east side of the plateau and the main rotors struck the side of the hill. The aircraft tumbled down the approx(imately) 400 yard 60 degree cliff in a violent manner with pieces of the aircraft busting apart and disintegrating all the way down the hill." The IP was interviewed by two inspectors from the Federal Aviation Administration's Boise flight Standards District office (FSDO) on April 21, 1998, and essentially related the same information as contained in his statement with the following exceptions. He reported to the inspectors that as he approached the landing area "planning to demonstrate a pinnacle landing" - "he thought the wind had changed and he was now experiencing a quartering tailwind" (refer to attached FAA Record of Conference). There were no known witnesses to the accident. PERSONNEL INFORMATION The IP, who occupied the left seat, reported a total of 613 hours of flight experience of which 565 hours were logged as pilot-in-command and 577 were logged in rotorcraft. He also reported a total of 397 hours of instructor time (all rotorcraft). Of this total flight experience, 17 hours were logged in the Hughes 269 rotorcraft and 8 hours of this was instructor time. He also reported having flown a total of 3 hours in the previous 90 days, all in the Hughes 269. The SP, who occupied the right seat, maintained a personal flight log which was reviewed and showed 123 hours of flight experience of which 34 hours were logged as pilot in command and 122 were logged in rotorcraft. Of this total flight experience, 90 hours were logged in the Hughes 269 rotorcraft which included 34 hours of pilot-in-command time. He also reported having flown a total of 15 hours in the previous 90 days, all in the Hughes 269. The pilot's first flight in N5161E was logged on July 14, 1997, and all 57 remaining flights logged in his logbook (the last being April 7, 1998) were in the accident aircraft. AIRCRAFT INFORMATION The aircraft was owned by the student pilot and records maintained by the FAA showed that it had been registered in his name September 17, 1997. The aircraft log showed the aircraft last inspection, an annual/100 hour inspection, was conducted on April 1, 1998, at an aircraft total time of 4729.8 hours (Hobbs = 683.8 hours). The engine log showed the aircraft last inspection, a 100 hour inspection, was conducted on April 1, 1998, at an engine total time since overhaul of 907.8 hours. The time between this inspection and the date of the accident was not known. The instructor reported that there was no mechanical malfunction with the rotorcraft during the accident flight. METEOROLOGICAL INFORMATION Surface winds (magnetic) for the following observation facilities were recorded at the noted times: Caldwell, Idaho (EUL), located 11 nm South of the site: 1556 hours MDT: from 120 deg at 9 knots 1616 hours MDT: from 110 deg at 8 knots 1636 hours MDT: from 110 deg at 9 knots, gusts to 14 knots 1656 hours MDT: from 170 deg at 5 knots, gusts to 17 knots 1716 hours MDT: from 140 deg at 8 knots Ontario, Oregon (ONO), located 24 nm WNW of the site: 1556 hours MDT: from 090 deg at 10 knots 1653 hours MDT: from 170 deg at 12 knots 1753 hours MDT: from 260 deg at 14 knots, gusts to 20 knots Boise, Idaho (BOI), located 20 nm ESE of the site: 1556 hours MDT: from 310 deg at 03 knots 1656 hours MDT: from 130 deg at 08 knots 1756 hours MDT: from 110 deg at 08 knots WRECKAGE AND IMPACT INFORMATION On site examination of the wreckage was conducted on April 12, 1998, by two inspectors from the FAA's Boise FSDO. The latitude and longitude of the accident was provided by search and rescue personnel via the Gem County Sheriff's Office and was noted as 43 degrees 49.13 minutes North and 116 degrees 39.13 minutes West respectively. The elevation of the initial ground contact site was approximately 3,000 feet above mean sea level (MSL) and on the northeast edge of a plateau. The terrain at this point dropped rapidly off at a -45 degree slope towards the north northeast (refer to DIAGRAM I and photograph 1). The inspectors reported observing "skid" marks on the top of the plateau approximately 30 feet to the northeast of a rapid drop-off in terrain. The marks measure approximately seven feet in length, were roughly parallel and spaced about six feet apart. The general orientation of the skid marks was along a 300/120 degree magnetic bearing line (refer to DIAGRAM I and photograph 2). They also reported that the wreckage distribution was along a track approximately perpendicular to the track line of the skids marks. This distribution was downslope along an approximate 030 degree bearing (refer to photograph 3). The cockpit area, including the two pilot seats, was found at the bottom of the ravine (refer to photographs 4 and 1 and ATTACHMENT F-I). MEDICAL AND PATHOLOGICAL INFORMATION Post mortem examination of the student pilot was conducted by Diana L. Claassen, M.D., on April 13, 1998, at the facilities of St. Alphonsus Regional medical Center, Boise, Idaho. Toxicological evaluation of samples from the student pilot was conducted by the FAA's Toxicology and Accident Research Laboratory and the following findings were reported (refer to attached report): Fluoxetine detected in urine, and in blood (0.174 ug/mL). Norfluoxetine detected in urine, and in blood (0.281 ug/mL). ADDITIONAL INFORMATION The aircraft airframe and engine log as well as the student pilot's flight log were returned via Federal Express to the instructor pilot on October 26, 1998.
The instructor pilot's failure to maintain the proper rate of descent on landing. Factors were a sudden wind shift, the instructor pilot's lack of recent experience, and terrain drop-off.
Source: NTSB Aviation Accident Database
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