14 CFR Part 91: General Aviation
Accident occurred Wednesday, May 02, 2012 in Valley Falls, KS
Probable Cause Approval Date: 08/29/2012
Aircraft: BELL 206B, registration: N85RB
Injuries: 3 Minor.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The helicopter, with the pilot and two passengers aboard, was hovering about 100 to 150 feet above ground level with a quartering tailwind. As the pilot turned the helicopter to the right, the helicopter started to spin, as reported by the pilot and several witnesses. He applied full left pedal and left forward cyclic, and slightly reduced power to stop the rotation. The pilot added that he sensed the loss of tail rotor effectiveness (LTE) and continued with the control inputs to fly out of the LTE. The pilot was unable to regain control of the helicopter before it impacted the ground. The pilot reported no preimpact mechanical malfunctions or failures with the helicopter that would have precluded normal operation. Based on the flight conditions at the time, the accident sequence is consistent with the helicopter encountering a LTE event.
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The pilot’s inadequate compensation for the wind conditions during a hover maneuver, which resulted in a loss of tail rotor effectiveness.
On May 2, 2012, about 0920 central daylight time, a Bell 206B Helicopter, N85RB, impacted terrain following a loss of control, nearValley Falls, Kansas. The commercial rated pilot and two passengers received minor injuries. The helicopter sustained substantial damage. The helicopter was registered to a private individual and operated by Hawkeye Helicopters, Ottawa, KS. Day visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91 aerial observation flight.
Several witnesses reported the helicopter “spinning” before the crash. The helicopter impacted the ground near a footpath, with trees on either side of the path. The helicopter came to rest on its left side, with the tailboom and left skid separated from the fuselage. The pilot stated that the engine continued to run for a brief time after the accident.
The pilot reported that during a 100-150 agl (above ground level) hover, the helicopter started an uncommanded right turn. He applied left full pedal, left-forward cyclic, and a slight reduction of power, to stop the rotation. The pilot added that he sensed the loss of tailrotor effectiveness (LTE), and continued with the control inputs to fly out of the LTE. Unable to get the helicopter to stop rotating, the pilot elected to enter an autorotation aiming for an open area, between a row of trees.
The responding Federal Aviation Administration (FAA) inspector stated that the pilot reported that during an out-of-ground hover, the helicopter had a quartering tailwind. The pilot initiated a right turn and the helicopter started to spin. The inspector added that the accident pilot had recently received his rotorcraft-helicopter rating based on prior military experience; however, the pilot did not have much recent helicopter experience. On the NTSB Pilot/Operator Aircraft Accident/Incident Report, 6120.1 form, the pilot reported a total of 2,398 flight hours in rotorcraft, with 2.1 hours in the accident make/model of helicopter.
FAA Advisory Circular (AC) 90-95, Unanticipated Right Yaw in Helicopters, dated February 26, 1995 states that the loss of tail rotor effectiveness (LTE) is a critical, low-speed aerodynamic flight characteristic which could result in an uncommanded rapid yaw rate which does not subside of its own accord and, if not corrected, could result in the loss of aircraft control. It also states, "LTE is not related to a maintenance malfunction and may occur in varying degrees in all single main rotor helicopters at airspeeds less than 30 knots."
Paragraph 6 of the AC covered conditions under which LTE may occur. It states:
"Any maneuver which requires the pilot to operate in a high-power, low-airspeed environment with a left crosswind or tailwind creates an environment where unanticipated right yaw may occur."
Paragraph 9 of the AC states: "When maneuvering between hover and 30 knots: (1) Avoid tailwinds. If loss of translational lift occurs, it will result in an increased high power demand and an additional anti-torque requirement. (2) Avoid out of ground effect (OGE) hover and high power demand situations, such as low-speed downwind turns. (3) Be especially aware of wind direction and velocity when hovering in winds of about 8-12 knots (especially OGE). There are no strong indicators to the pilot of a reduction of translation lift. (4) Be aware that if considerable amount of left pedal is being maintained a sufficient amount of left pedal may not be available to counteract an unanticipated right yaw. (5) Be alert to changing aircraft flight and wind conditions which may be experienced when flying along ridge lines and around buildings. (6) Stay vigilant to power and wind conditions."
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VALLEY FALLS — Jerry Logsdon had just downed some coffee and finished his morning routine at home Wednesday when he saw a helicopter spinning out of control above Valley Falls.
“I said to myself, ‘It’s going down. It’s going to crash,’ ” Logsdon said. “It went over the trees, and then I heard a thud.”
Logsdon, who is assistant fire chief for Jefferson County Fire
District No. 11 and an emergency medical technician, contacted 911 and
then drove to the fire station to get an ambulance.
He drove an ambulance to the site of the helicopter crash, which is
northwest of the K-4 and K-16 junction, and discovered three people had
exited the wreckage.
The pilot, Wayne Spry, 62, of Wakarusa, and his two passengers, Jerry
Senger, 45, and Clint Shoemaker, 32, both of Tonganoxie, received minor
injuries.
“They were pretty fortunate,” said Jefferson County Sheriff Jeff Herrig. “Very lucky. They took a pretty good fall.”
Senger and Shoemaker, Southern Star Central Gas employees, were
inspecting natural gas pipelines before the crash. The company, based in
Owensboro, Ky., is a natural gas transmission system spanning more than
6,000 miles in the Midwest and mid-continent regions of the United
States. Its facilities are in Kansas, Oklahoma, Missouri, Wyoming,
Colorado, Texas, Nebraska and Kentucky. It serves major markets, such as
Wichita and Kansas City.
The helicopter, a 1972 206 Bell, is owned by Hawkeye Helicopter, of
Ottawa, Herrig said. Hawkeye Helicopter has a fleet of 14 aircraft, a
staff of 17 and accounts “for a substantial portion of all aerial
patrols in the Midwest,” according to its website.
Neither Hawkeye Helicopter nor Southern Star would comment on the crash.
The Kansas Highway Patrol was called at 9:50 a.m. to the crash site,
which is just east of a ballpark and a few blocks from schools in this
Jefferson County town.
The pilot and his passengers were taken to St. Francis Health Center in Topeka, where they were treated and released.
The sheriff’s office, as well as Kansas Highway Patrol troopers,
firefighters and Valley Falls Police Department officers, were still at
the scene Wednesday afternoon.
Herrig arrived shortly after ambulances did.
“When I got here, the tree fell,” the sheriff said, pointing to a
tree that had fallen on the helicopter. “It was about 10 or 15 minutes
after the crash.”
The red and white helicopter landed on its side near the Delaware
River in an old railroad bed that now serves as a walking trail. The
helicopter struck some trees on descent and came to rest between two
tree lines in a clearing. Glass, maps and other items were scattered
around the craft.
The Federal Aviation Administration is investigating. Herrig said the
FAA will either choose to remove the helicopter to a different location
for further investigation or will release it to its owner or the
insurance company.
The helicopter crash drew several members of the media to this small
town of about 1,190. Television stations from the Kansas City area, as
well as several area newspaper reporters, showed up at the crash site to
conduct interviews, take photographs and gather footage. “I even talked to CNN,” Herrig said.
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