GAA15CA204

NTSB accident investigation · Airbus AS350-B2 · Tucson, AZ · July 29, 2015

Accident · Minor injuriesData collectionFinal report
Date
July 29, 2015, 16:45 local (23:45 UTC)
Place
Tucson, AZ
Injuries
1 minor, 1 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N6095UAirbus AS350-B2
Defining event
Maneuvering-low-alt flying: Low altitude operation/event
Weather
Visual (VMC) · Day
Status
Completed · report December 3, 2015
Report
Approved by Office Director
NTSB office
General Aviation Accidents
Parties
FAA
FAA report
20150729023209A
Case key
91673

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 misperception of the helicopter's altitude in relation to the runway surface during a low altitude maneuver, resulting in ground impact.

Findings · 3

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.

Perception/orientation/illusion: perceptionPersonnel issues › Psychological · Instructor/check pilotEurocopter AS 350 B2 ECUREUIL: 1 caseAll aircraft: 61 casesProbable cause
Use of equip/info: aircraft controlPersonnel issues › Task performance · Instructor/check pilotEurocopter AS 350 B2 ECUREUIL: 2 casesAll aircraft: 9,295 casesProbable cause
Performance/control parameters: altitudeAircraft › Aircraft oper/perf/capability · Not attained/maintainedEurocopter AS 350 B2 ECUREUIL: 1 caseAll aircraft: 1,310 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/Operator Aircraft Accident Report, the operator reported that, the flight instructor(CFI) was demonstrating the flare portion of an autorotation to the pilot-rated student when the aircraft continued through the power recovery point and impacted the runway. However, during the interview with the CFI and the student, both pilots referred to "flare portion" as the quick stop maneuver, which was the maneuver being performed at the time of the accident. Both pilots stated that they hover taxied to the approach end of the runway, stopped over the runway numbers and established a hover between 65-75 feet above ground level. They reported that they hovered over the runway numbers, facing in the direction of the runway heading, and the CFI described the intricacies of the quick stop maneuver. The CFI specified that the maneuver would terminate to a hover, and initiated the quick stop demonstration by accelerating to the airspeed of 65 knots. The CFI reported that as he talked through the maneuver, he lowered the collective and applied aft cyclic. He stated that as the helicopter began to settle, he misperceived the helicopters altitude in relation to the ground and the helicopter skids impacted the ground hard. Both pilots stated that the CFI responded by increasing collective and the helicopter ascended, started moving aft, and the tail boom separated impacting the left side of the fuselage. The student reported that he and the CFI were both on the controls after the first impact. Both pilots recalled lowering the collective in order to set the helicopter down, the helicopter remained in a level pitch attitude, but yawed left and landed on the skids. The helicopter remained on the ground as the left yaw continued, and the engine was shut down. Both pilots reported that the helicopter spun on the skids, in two complete circles while on the ground, before coming to a stop. The tail boom and main rotor system sustained substantial damage. Both pilots reported that there were no pre-impact mechanical malfunctions or anomalies with any portion of the helicopter that would have prevented normal operations.

Factual narrative

According to the Pilot/Operator Aircraft Accident Report, the operator reported that, the flight instructor(CFI) was demonstrating the flare portion of an autorotation to the pilot-rated student when the aircraft continued through the power recovery point and impacted the runway. However, during the interview with the CFI and the student, both pilots referred to "flare portion" as the quick stop maneuver, which was the maneuver being performed at the time of the accident. Both pilots stated that they hover taxied to the approach end of the runway, stopped over the runway numbers and established a hover between 65-75 feet above ground level. They reported that they hovered over the runway numbers, facing in the direction of the runway heading, and the CFI described the intricacies of the quick stop maneuver. The CFI specified that the maneuver would terminate to a hover, and initiated the quick stop demonstration by accelerating to the airspeed of 65 knots. The CFI reported that as he talked through the maneuver, he lowered the collective and applied aft cyclic. He stated that as the helicopter began to settle, he misperceived the helicopters altitude in relation to the ground and the helicopter skids impacted the ground hard. Both pilots stated that the CFI responded by increasing collective and the helicopter ascended, started moving aft, and the tail boom separated impacting the left side of the fuselage. The student reported that he and the CFI were both on the controls after the first impact. Both pilots recalled lowering the collective in order to set the helicopter down, the helicopter remained in a level pitch attitude, but yawed left and landed on the skids. The helicopter remained on the ground as the left yaw continued, and the engine was shut down. Both pilots reported that the helicopter spun on the skids, in two complete circles while on the ground, before coming to a stop. The tail boom and main rotor system sustained substantial damage. Both pilots reported that there were no pre-impact mechanical malfunctions or anomalies with any portion of the helicopter that would have prevented normal operations.

Aircraft

Registration
N6095U
Reported as
Airbus AS350-B2
Category
Helicopter
Serial number
2699
Built
1993
Airframe hours
12,629.3
Engine
Turbomeca Arriel/1D1, 732 horsepower, turbo shaft
Damage
Substantial damage
Flight
Public aircraft - federal · Public use
Operator
US Department Of Homeland Security
Registered owner
US Department Of Homeland Security
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · July 6, 2015 · 80 hours before
Departed
DMA · Tucson, AZ
Destination
RYN · Tucson, AZ
Flight plan
Company VFR
Airport
RYN · Ryan Field, runway 24R, 4,900 × 75 ft, asphalt
Equipment
None

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
Flight instructor
Age
48
Injuries
Minor
Certificates
Flight instructor, Commercial
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Helicopter, Airplane
Medical
Class 2, With waivers/limitations
Last flight review
July 15, 2015
Seat
Left
Restraint
4-point
Toxicology
Performed
Flight hours
6,399 total · 2,178 in this make and model · 5,284 as pilot in command · 62 in the last 90 days · 29 in the last 30 days · 4 in the last 24 hours
Role
Pilot
Age
46
Injuries
None
Certificate
Commercial
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane, Helicopter
Medical
Class 2, Without waivers/limitations
Last flight review
June 3, 2015
Seat
Right
Restraint
4-point
Toxicology
Performed
Flight hours
2,500 total · 200 in this make and model · 1,160 as pilot in command · 31 in the last 90 days · 1 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
270° at 3 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
95 °F, dew point 61 °F
Altimeter
29.98 inHg
Observed at
RYN

Docket · 3

The files NTSB released with the investigation on November 17, 2015, on NTSB’s docket system: statements, records, photos and specialists’ reports. 2.5 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.