ERA10TA501

NTSB accident investigation · Eurocopter AS-350 · Covington, GA · September 24, 2010

Accident · Minor injuriesFinal report
Date
September 24, 2010, 16:34 local (20:34 UTC)
Place
Covington, GA
Injuries
2 minor
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N91DKEurocopter AS-350
Defining event
Maneuvering-hover: Loss of control in flight
Weather
Visual (VMC) · Day
Status
Completed · report July 21, 2011
Report
Approved by Office Director
NTSB office
Eastern Region Aviation
Parties
FAA/FSDO
FAA report
20100924048139A
Case key
77394

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

The flight instructor's loss of control of the helicopter during the intentional demonstration of a low speed, hydraulics-off maneuver, that was warned against in the helicopter manufacturer's flight manual.

Findings · 2

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Action: incorrect action performancePersonnel issues › Action/decision · Instructor/check pilotEurocopter AS 350 B2: 2 casesAll aircraft: 1,386 casesProbable cause
Hydraulic power system: hydraulic, main systemAircraft › Aircraft systems · Simulated malf/failureEurocopter AS 350 B2: 3 casesAll aircraft: 27 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

According to the pilot of the helicopter, the instructor simulated a hydraulics failure by “turning off” the flight control hydraulics switch, in order to perform a hydraulics-off, run-on landing as the remedial action to the simulated emergency. As the helicopter slowed over the runway, the nose yawed to the left, and the pilot was unable to correct the yaw with right pedal input. The instructor took control of the helicopter, and completed a low-level, left-hand orbit to demonstrate and complete the maneuver. As the helicopter completed the left orbit and lined up for landing, it “rolled wings level” but then continued to roll to the right and collided with terrain. The pilot said that the entire maneuver was conducted hydraulics-off, and that he felt the instructor had control of the helicopter until it rolled past wings-level to the right. The pilot added that the instructor had successfully completed a similar maneuver earlier in the day, without restoring the flight control hydraulics. According to the manufacturer's Flight Manual (Emergency Procedures) and the Flight Manual Supplement, Hydraulic Pressure Failure Training Procedures, "CAUTION: DO NOT ATTEMPT TO CARRY OUT HOVER FLIGHT OR ANY LOW SPEED MANEUVER WITHOUT HYDRAULIC PRESSSURE ASSISTANCE. THE INTENSITY AND DIRECTION OF THE CONTROL FEEDBACK FORCES WILL CHANGE RAPIDLY. THIS WILL RESULT IN EXCESSIVE PILOT WORKLOAD, POOR AIRCRAFT CONTROL, AND POSSIBLE LOSS OF CONTROL." Both the pilot and the instructor stated that there was nothing wrong with the performance and handling of the helicopter.

Factual narrative

On September 24, 2010, at 1634 eastern daylight time, an American Eurocopter AS-350B2, N91DK, operated by the Dekalb County Police, was substantially damaged after a loss of control while landing at Covington Airport (9A1), Covington, Georgia. The certificated commercial pilot and the certificated flight instructor sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the local public use instructional flight. The flight instructor reported to witnesses, police, and to a Federal Aviation Administration (FAA) inspector that he and the pilot had been performing hydraulics-off maneuvers, the helicopter "got away from them," and control could not be regained prior to ground contact. According to the pilot, he was conducting recurrent training with the instructor, a contractor, who was not affiliated with the Dekalb County Police. He said they had returned from a meal break, and that this was the second flight of the day. According to the pilot, the instructor simulated a hydraulics failure by "turning off" the flight control hydraulics switch, and he was to then perform a hydraulics-off, run-on landing as the remedial action to the simulated emergency. As the helicopter slowed over the runway, the nose yawed to the left, and the pilot was unable to correct the yaw with right pedal input. The instructor announced and took control of the helicopter, and completed a low-level, left-hand orbit to demonstrate and complete the maneuver. According to the pilot, as the helicopter completed the left orbit and lined up for landing, it "rolled wings level" but then continued to roll to the right and collided with terrain. He said that the entire maneuver was conducted hydraulics-off, and that he felt the instructor had control of the helicopter until it rolled past wings-level to the right. The pilot added that the instructor had successfully completed a similar maneuver earlier in the day, without restoring the flight control hydraulics. Both the pilot and the instructor stated that there was nothing wrong with the performance and handling of the helicopter. The pilot held a commercial pilot certificate with a rating for rotorcraft helicopter. His most recent FAA second class medical certificate was issued July 14, 2010. The pilot reported 929 total hours of flight experience, of which 929 hours were in the accident helicopter make and model. The flight instructor held a commercial pilot certificate with ratings for airplane single engine, multiengine, rotorcraft-helicopter, and instrument airplane and helicopter. He held a flight instructor certificate for airplane single engine, rotorcraft-helicopter, and instrument airplane and helicopter. His most recent FAA second class medical certificate was issued April 12, 2010. The instructor reported 4,100 total hours of flight experience on that date. According to the operator, the helicopter had accrued 3,158 total aircraft hours. Its most recent 100-hourinspection was completed on August 12, 2010, at 3,100 total aircraft hours. At 1650, the weather reported at LZU, 21 miles north of the site, included scattered clouds at 5,500 feet and winds from 200 degrees at 5 knots. The visibility was 10 miles. The temperature was 32 degrees Celsius (C) and the dew point was 21 degrees C. The altimeter setting was 30.09 inches of mercury. Examination of the helicopter by an FAA inspector revealed the helicopter sustained substantial damage to cockpit, cabin structure, and landing gear. According to the Eurocopter AS 350 B2 Flight Manual (Emergency Procedures) and Flight Manual Supplement, Hydraulic Pressure Failure Training Procedures, "CAUTION: DO NOT ATTEMPT TO CARRY OUT HOVER FLIGHT OR ANY LOW SPEED MANEUVER WITHOUT HYDRAULIC PRESSSURE ASSISTANCE. THE INTENSITY AND DIRECTION OF THE CONTROL FEEDBACK FORCES WILL CHANGE RAPIDLY. THIS WILL RESULT IN EXCESSIVE PILOT WORKLOAD, POOR AIRCRAFT CONTROL, AND POSSIBLE LOSS OF CONTROL."

Aircraft

Registration
N91DK
Reported as
Eurocopter AS-350 (B2)
Category
Helicopter
Serial number
3497
Airframe hours
3,158
Engine
Turbomeca Arriel 1D1, 715 horsepower, turbo shaft
Damage
Substantial damage
Flight
Public aircraft - local · Public use
Operator
Dekalb County Police Services
Registered owner
Dekalb County Police Services
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · August 12, 2010 · 58 hours before
Departed
9A1 · Covington, GA
Destination
9A1 · Covington, GA
Airport
9A1 · Covington Municipal Airport, runway 28, 5,500 × 75 ft, asphalt

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew · 2

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
45
Injuries
Minor
Certificate
Commercial
Medical
Class 2, Without waivers/limitations
Last flight review
April 17, 2006
Seat
Right
Flight hours
929 total · 929 in this make and model · 863 as pilot in command · 45 in the last 90 days · 18 in the last 30 days · 0 in the last 24 hours
Role
Flight instructor
Age
42
Injuries
Minor
Certificate
Commercial
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Helicopter, Airplane
Medical
Class 2, Without waivers/limitations
Seat
Left
Flight hours
4,100 total

Weather

Conditions
Visual (VMC) · Day
Wind
200° at 5 knots
Visibility
10 statute miles
Lowest ceiling
9,500 ft
Temperature
90 °F, dew point 70 °F
Altimeter
30.09 inHg
Observed at
LZU, 21 nm away

Docket · 6

The files NTSB released with the investigation on June 2, 2011, on NTSB’s docket system: statements, records, photos and specialists’ reports. 2.9 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.