NTSB Identification: CEN13LA099
14 CFR Part 91: General Aviation
Accident occurred Friday, December 07, 2012 in Abilene, TX
Probable Cause Approval Date: 07/23/2013
Aircraft: ENSTROM F-28C, registration: N574H
Injuries: 2 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
A student pilot and flight instructor departed with full fuel tanks on a round-robin cross-country flight in the student pilot's helicopter. The first three legs were uneventful with landings at all three locations. The flight instructor and the student pilot did not visually check the fuel tanks at stops during the flight. On the last leg, the instructor noted the fuel gauges and made the decision to continue to the destination. The student pilot told the flight instructor that the fuel quantity on board the helicopter was low. The flight instructor informed him that the fuel gauges were often faulty and that they had enough fuel to complete the return leg of the flight. About 2 miles from the destination, the helicopter yawed left twice, and the engine and rotor rpm began to decay. The instructor lowered the collective and leveled the helicopter. The rotor rpm decayed even further, to the point that it was below the minimum for autorotative descent. The instructor pushed the nose over then brought the helicopter back to a level attitude. He reported that this caused the blades to cone upward and increased the rotor rpm, but the rpm was still below the red line. The instructor nosed the helicopter over again and turned left but was unable to regain rotor speed. The instructor was certain that, in addition to the loss of engine power, the overrunning clutch had not disengaged the engine from the transmission. The instructor leveled the helicopter about 3 feet above the ground and applied collective but reported that only about one-third of normal rotor rpm was available. The helicopter landed hard and the main rotor blades impacted the tailboom. A postaccident examination revealed that the fuel tanks contained no usable fuel, and, when serviced with fuel, the engine was operational. An examination of the overrunning clutch operation revealed no anomalies.
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The flight instructor's failure to conduct an autorotation following the loss of engine power due to fuel exhaustion. Contributing to the accident was the failure of the flight instructor and the student pilot to visually check fuel levels to ensure adequate fuel on board for the planned flight.
On December 7, 2012, about 1545 central standard time, an Enstrom F-28C helicopter, N574H, impacted terrain during an autorotation following a loss of engine power during approach to the Abilene Regional Airport (ABI), near Abilene, Texas. The certified flight instructor and student pilot reported no injuries. The helicopter sustained substantial tailboom damage. The helicopter was registered to and operated by the student pilot under the provisions of 14 Code of Federal Regulations Part 91 as an instructional flight. Visual flight rules (VFR) conditions prevailed for the flight, which did not operate on a VFR flight plan. The flight originated from the Brownwood Regional Airport (BWD), near Brownwood, Texas, at time unknown and was destined for ABI.
According to the flight instructor’s accident report, the instructor and student pilot arrived at 0930 outside a fixed base operator at the ABI. They discussed subjects including his helicopter; N574H, helicopter logbooks, maintenance history, helicopter airworthy condition, preflight actions, the student pilot’s aviation experience, and various other topics for about an hour. There were no pending maintenance issues detected and after an extensive preflight inspection, the instructor found the helicopter to be in an airworthy condition. The instructor indicated that the fuel tanks were completely filled, which would have given them “40 gallons of total fuel.” The student requested that they fly to Albany, Eastland, Brownwood then return to Abilene. The first three legs were uneventful with landings at all three locations. On the last leg, he noted the fuel level and made the decision to continue to ABI. The fuel gauge read 3/8ths full. The instructor estimated that out of 40 gallons total fuel, the helicopter passed over BWD with 15 gallons of fuel. He further figured that with a fuel burn of 13.5 gallons per hour and 30 to 35 minutes to ABI, the helicopter should land with the required 20-minute reserve. Approximately four miles from ABI, the flight was cleared to pass behind a Beechcraft on final to 17L. At 2 miles from ABI, the helicopter yawed left briefly. The instructor stated that he turned his attention from the Beechcraft to the engine instruments and to what the student pilot was doing. The helicopter yawed to the left one more time and the engine and rotor RPM began to decay. The instructor lowered the collective, let the student pilot know that he was now flying the helicopter, and leveled the helicopter for a 70-knot attitude. This made the rotor RPM decay even further, where it was now under the minimum for autorotative descent. The instructor pushed the nose over then back to nose level. He reported this caused the blades to cone upward and increase rotor RPM, but it was still below the red line. The instructor nosed the helicopter over again and turned left. This caused the rotor to cone upward and “unload”. He said that this maneuver should have regained “rotor speed to the high side but was only slightly effective.” The instructor, in part, reported:
It was now fairly certain to me that I was not only having an
engine failure, but also the over running clutch had not
disengaged the engine from the transmission. I was now facing
to the South and rotor RPM at the red line once again. I flared
the helicopter at 30 feet AGL [above ground level]. This slowed
the helicopter down but now the rotor system was “loaded” and
being dragged down to 200 RPM. At 3 feet I leveled the
helicopter and applied collective to cushion the landing but I
had only about 1/3rd of the rotor RPM normally available. The
helicopter landed level with very little forward movement. One
of the main rotor blades contacted the tailboom causing the
helicopter to spin to the left approximately 60 degrees. The
next rotor blade contacted to tailrotor debris. The third main
rotor blade had only the damage caused by the sudden stoppage.
According to the student pilot’s accident report, the student pilot voiced his opinion on the low fuel quantity on board the helicopter. He said that the flight instructor informed him the fuel gauges are often faulty and that they had enough fuel to complete the return leg of the flight to ABI.
Federal Aviation Administration inspectors oversaw a postaccident examination of the helicopter. A mechanic assisted the inspector’s examination where less than one gallon of fuel was drained from each of the right and left hand fuel tank sumps. The fuel strainer and fuel injection servo screen were examined and reinstalled. The helicopter was serviced with four gallons of 100 low lead aviation gasoline. The engine subsequently started and ran smoothly for five minutes. An inspector examined the over running clutch operation and no anomalies were detected.
The Enstrom rotorcraft flight manual (FM) for the F-28C helicopter preflight inspection checklist indicated that the right hand and left hand fuel tanks are to be visually checked in reference to their quantity and confirm both fuel tank caps are secured. The checklist further indicated to drain both the right hand and left hand tank sumps. The FM, in part, stated:
ROTOR - FLIGHT LIMITATIONS (POWER OFF)
Maximum: ............................ 385 rpm
Minimum .............................. 332 rpm
...
ENGINE WARMUP AND GROUND CHECK...
4. Gently close throttle to split tachometer needles to check
proper operation of over running clutch.
...
ENGINE FAILURE
1. Enter normal autorotation and stabilize at 58 MPH (minimum
rate of [descent]). (See Height Velocity information, pages FM-
5-4 and FM-5-5.)
NOTE: Due to high rates of descent at forward speeds, sustained
auto rotation speed is limited to 85 MPH to
8200 ft. Above 8200 ft., see FM-5-1.
Maximum glide distance in autorotation is attained
at 80 mph and 332 rotor rpm. (Reduce collective to
build RPM prior to touchdown.)
At 1452, the recorded weather at ABI indicated that the wind was calm.
Enstrom Service Directive Bulletin No. 0092, Fuel Quantity System Calibration, indicated that one gallon per fuel tank was unusable fuel and in part, stated:
Pilots can assist in determining if the fuel quantity system is
operating correctly by monitoring the fuel quantity indication
prior to and after refueling and comparing the indications to
the total quantity of fuel used in servicing the tanks. In
addition, a fuel dipstick, [part number] 28-12478-11 for all
20 gallon (40 gallon total capacity) tanks, should be used
during preflight inspection to verify fuel quantity on all
aircraft so equipped.
Neither the flight instructor nor the student pilot visually checked the fuel level in the fuel tanks at any of the stops during the round robin cross-country flight.
NTSB Identification: CEN13LA099
14 CFR Part 91: General Aviation
Accident occurred Friday, December 07, 2012 in Abilene, TX
Aircraft: ENSTROM F-28C, registration: N574H
Injuries: 2 Uninjured.
This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
On December 7, 2013, about 1545 central standard time, an Enstrom F-28C helicopter, N574H, impacted terrain during an autorotation following a loss of engine power during approach to the Abilene Regional Airport (ABI), near Abilene, Texas. The certified flight instructor and student pilot reported no injuries. The airplane sustained substantial tailboom damage. The airplane was registered to and operated by the student pilot under the provisions of 14 Code of Federal Regulations Part 91 as an instructional flight. Visual flight rules (VFR) conditions prevailed for the flight, which did not operate on a VFR flight plan. The flight originated from the Brownwood Regional Airport, near Brownwood, Texas, at time unknown and was destined for ABI.
At 1452, the recorded weather at ABI was: Wind calm; visibility 10 statute miles; sky condition clear; temperature 18 degrees C; dew point 4 degrees C; altimeter 29.82 inches of mercury.
IDENTIFICATION
Regis#: 574H Make/Model: F28C Description: ENSTROM F-28C
Date: 12/07/2012 Time: 2145
Event Type: Accident Highest Injury: None Mid Air: N Missing: N
Damage: Substantial
LOCATION
City: ABILENE State: TX Country: US
DESCRIPTION
N574H ENSTROM F-28C ROTORCRAFT FORCE LANDED IN A FIELD, 3 MILES FROM
ABILENE, TX
INJURY DATA Total Fatal: 0
# Crew: 2 Fat: 0 Ser: 0 Min: 0 Unk:
# Pass: 0 Fat: 0 Ser: 0 Min: 0 Unk:
# Grnd: Fat: 0 Ser: 0 Min: 0 Unk:
OTHER DATA
Activity: Training Phase: Unknown Operation: OTHER
FAA FSDO: LUBBOCK, TX (SW13) Entry date: 12/10/2012
A flying lesson came to an abrupt ending Friday after a helicopter’s engine failed, forcing the instructor to make an emergency landing near Abilene Regional Airport, according to the Texas Department of Public Safety.
Robert Welch, 50, of Abilene, was piloting an Enstrom helicopter when the aircraft’s engine died shortly after lifting off from the airport at about 4 p.m., said Senior Trooper Sparky Dean, spokesman for the DPS, in a statement.
The helicopter had traveled a little more than a mile before Welch made a “soft landing,” according to the DPS statement.
Welch and student Neil Overton, 41, of Throckmorton, were not injured in the incident, Dean said.
A soft landing is characterized as one that causes little or no damage to the craft and little or no injuries to occupants.
The Federal Aviation Administration has been notified of the incident, according to the DPS.
Story: http://www.reporternews.com
Helicopter Makes Emergency Landing ... And down it went, straight to Mr. Compton's wheat field.
"All of a sudden they made a little turn and they hit hard, they hit the ground really hard. And I immediately called 911," explains Compton.
The emergency landing was due to total engine failure.
"If you hear helicopters and airplanes fly by like I do, I lived out here all my life so I know what they're suppose to sound like and this one was not normal," he says.
Robert Welch from Abilene was the instructor and pilot of the helicopter. Neil Overton from Throckmorton was the student but he was also the owner.
"One of the guys was hanging out the front and I thought he was the one hurt," explain Compton. "He got out and walked out there on the wheat and layed down, I thought 'oh boy he's hurt' but he seemed to be ok."
Both men were able to walk away from the accident with no injuries while managing to be courteous to field owner, Mr. Compton.
"They did a very good job. They missed the cows and landed perfect out in the field."
Unfortunately for the helicopter owner, it was a new purchase.
Fortunately State Troopers say Mr. Overton had just recently made his first insurance payment.
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