GAA18LA131

NTSB accident investigation · Robinson Helicopter R22 · Charleston, SC · February 14, 2018

Accident · No injuriesLimited investigationFinal report
Date
February 14, 2018, 13:30 local (18:30 UTC)
Place
Charleston, SC
NTSB coordinates
32.4914, -79.5444 (estimated), outside the stated state
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N337HRobinson Helicopter R22
Defining event
Maneuvering: Loss of control in flight
Weather
Visual (VMC) · Day
Status
Completed · report November 6, 2019
Report
Approved by Office Director
NTSB office
General Aviation Accidents
Parties
FAA
FAA report
20180214012049A
Case key
96745

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

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Probable cause

The flight instructor’s abrupt evasive maneuver to avoid a reported unmanned aerial system, which resulted in a loss of forward airspeed and settling with power and a subsequent collision with trees and terrain.

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.

Use of equip/info: use of equip/systemPersonnel issues › Task performance · Instructor/check pilotRobinson Helicopter R22 BETA: 16 casesAll aircraft: 1,391 casesProbable cause
Performance/control parameters: prop/rotor parametersAircraft › Aircraft oper/perf/capability · Attain/maintain not possibleRobinson Helicopter R22 BETA: 37 casesAll aircraft: 182 casesProbable cause
Object/animal/substance: tree(s)Environmental issues › Physical environment · Effect on operationRobinson Helicopter R22 BETA: 7 casesAll aircraft: 933 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

During an instructional flight in the helicopter, the student pilot was on the controls. The flight instructor said the student had transitioned from a hover through effective transitional lift and established forward flight and then initiated a right turn. He added that, during the right turn, he and the student saw a small, white unmanned aerial system (UAS) about 10 ft in front of the helicopter at "eye level." The instructor took the flight controls and made a hard right and aft cyclic input. After the evasive maneuver, the helicopter had very little forward airspeed. The helicopter was about 40 ft above ground level as it began settling with power. The helicopter descended, and the tail rotor entered trees. The helicopter then developed a right spin, and the instructor rolled the throttle off to alleviate the spin and then increased the collective to try to cushion the landing. Subsequently, the helicopter impacted the ground and rolled over onto its right side. A UAS was not recovered. It is likely that the instructor's abrupt maneuver led to the loss of forward airspeed and the helicopter's subsequent descent into trees, which resulted in the right spin from which the instructor could not recover before impact with terrain.

Factual narrative

On February 14, 2018 about 1336 eastern standard time (EST), a Robinson Helicopters Inc., R22 Beta, N337H, landed hard in dense vegetation and the tailboom separated from the fuselage. The accident occurred about 5 miles southeast of Charleston Air Force/International Airport, South Carolina. The helicopter was registered to Spitzer Helicopter and was being operated by Holy City Helicopters as a visual flight rules (VFR), local instructional flight, under the provisions of Title 14 Code of Federal Regulations Part 91. The flight instructor and student were not injured. Visual meteorological conditions prevailed for the flight, and flight following was not in effect. The flight instructor reported that he had conducted training in the area previously and was familiar with the terrain and obstacles. The flight lesson was conducted to practice hovering, followed by a transition to forward flight. The instructor reported that the wind was from the west/northwest about 10 knots, and that the direction of takeoff was into the wind. According to the instructor, during the accident pattern the student had the flight controls and had transitioned the helicopter from a hover through effective translational lift and established forward flight. The student then initiated a right turn over dense vegetation when a small unmanned aerial system (UAS), which he described as a white quadcopter, appeared about 10ft in front of the helicopter at "eye level". The instructor took the flight controls and made a hard right and aft cyclic input to avoid the UAS. The evasive maneuver put the helicopter into a right quartering tailwind. After the evasive maneuver, the helicopter had some forward airspeed, "but not much". He was able to level the helicopter's attitude, but the helicopter began to descend quickly. The helicopter was about 40ft AGL and the instructor described the helicopter's descent as settling with power. The helicopter descended, and the tail rotor entered the trees and the helicopter developed a spin to the right. The instructor rolled the throttle off to alleviate the spin, and then tried to cushion the landing by increasing collective. The helicopter impacted the ground, continued spinning to the right, and subsequently rolled over onto its right-side. The helicopter sustained substantial damage to the tail rotor drive shaft. The student pilot reported that they were operating over an access road and that she had initiated a right turn, "when a small white drone came into our field of vision". The instructor immediately took the flight controls and increased the bank angle of the right turn to avoid the UAS. As the helicopter "swung around" to miss the UAS, the tail rotor stuck the tree tops, and they lost tail rotor authority. The instructor entered an autorotation, and the helicopter collided with trees. The helicopter descended in a spin, impacted terrain and rolled on to its right side. The day following the accident, Federal AviationAdministration, Aviation Safety Inspector's canvassed the vicinity of the accident, to include a housing development about ¼ mile from the accident site. The housing development was under construction and one member of the construction team remembered seeing the helicopter operating in the area about the time of the accident. There were several construction crews working during the time of the accident, and none of them recalled seeing a "drone". The flight instructor reported that there were no mechanical malfunctions or failures with the helicopter that would have precluded normal operation prior to the tail rotor strike. A canvas of the area by the FAA did not find any information about the Unmanned Aerial System or witnesses.

Aircraft

Registration
N337H
Reported as
Robinson Helicopter R22 (BETA II)
Category
Helicopter
Serial number
2999
Built
1999
Airframe hours
7,989
Engine
Lycoming O-360-J2A, 124 horsepower, reciprocating
Damage
Substantial damage
Flight
Instructional · Part 91
Operator
Holy City Helicopters
Registered owner
Spitzer Helicopter LLC
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · December 28, 2017
Departed
CHS · Charleston, SC
Destination
CHS · Charleston, SC
Equipment
Stall warning system

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
27
Injuries
None
Certificates
Commercial, Flight instructor
Instrument ratings
Helicopter
Medical
Class 1
Last flight review
April 30, 2017
Seat
Left
Restraint
3-point
Flight hours
2,480 total · 1,500 in this make and model · 2,430 as pilot in command · 70 in the last 90 days · 45 in the last 30 days
Role
Student pilot
Age
34
Injuries
None
Seat
Right
Flight hours
15 total · 15 in this make and model

Weather

Conditions
Visual (VMC) · Day
Wind
Calm
Visibility
10 statute miles
Temperature
64 °F, dew point 54 °F
Altimeter
30.44 inHg
Observed at
KCHS, 35 nm away

Docket · 7

The files NTSB released with the investigation on May 8, 2019, on NTSB’s docket system: statements, records, photos and specialists’ reports. 4.5 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.