- Date
- May 23, 2019, 14:10 local (19:10 UTC)
- Place
- St. Louis, IL
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N369PAGuimbal Cabri
- Defining event
- Landing-aborted after touchdown: Loss of control on ground
- Weather
- Visual (VMC) · Day
- Status
- Completed · report April 13, 2020
- Report
- Approved by Office Director
- NTSB office
- General Aviation Accidents
- Parties
- FAA
- FAA report
- 20190523005059A
- Case key
- 99479
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 improper emergency procedure instruction to the student pilot, which resulted in the student improperly using the throttle to correct the loss of yaw control, which resulted in ground impact and a dynamic rollover.
Findings · 4
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.
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
The flight instructor reported that, during a training flight in the helicopter, he briefed the student pilot on the procedures required to land with a simulated stuck left pedal. The student began a descent to enter a shallower-than-normal glidepath to the runway surface, and he completed his final checks for the maneuver and continued the approach. During the approach the flight instructor directed the student pilot to use "throttle manipulation to control the yaw caused by a fixed input on the anti-torque system." Upon contacting the runway, the helicopter veered left, and the instructor chose to abort the landing. As the helicopter lifted off, it began to rapidly yaw left while drifting left of the runway. Recognizing that the helicopter was in a spin, they attempted to correct by leveling the helicopter long enough to regain tail rotor authority. The helicopter's left skid impacted mud on the left side of the runway, and the helicopter rolled onto its left side. The helicopter sustained substantial damage to the main rotor, fuselage, and tailboom. The instructor reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation. A manufacturer's service letter, SL 19-002 A, stated, "During in-flight tail rotor control failure simulation, pilots should never use the twist grip to control yaw." Therefore, the flight instructor's direction to the student to use the throttle to correct the yaw was incorrect and led to ground impact and a dynamic rollover.
Factual narrative
The helicopter flight instructor reported that, during a training flight, he briefed the student pilot on the procedures required to land with a simulated stuck left pedal. The student began a descent to enter a shallower-than-normal glide path to the runway surface, and he completed his final checks for the maneuver and continued the approach. Upon contacting the runway, the helicopter veered to the left, and the instructor elected to abort the landing. As the helicopter lifted off, it began to yaw to the left at a rapid rate, while drifting to the left of the runway. Recognizing the helicopter was in a spin, they attempted to correct by leveling the helicopter "long enough for the aircraft to regain tail-rotor authority." The helicopter's left skid impacted the mud on the left side of the runway and the helicopter rolled onto its left side. The Federal Aviation Administration's Helicopter Flying Handbook, FAA-H-8083-21A, provides information and guidance in a section titled "Landing – Stuck Neutral or Right Pedal" which stated in part: The landing profile for a stuck neutral or a stuck right pedal is a low-power approach terminating with a running or roll-on landing. The approach profile can best be described as a shallow to normal approach angle to arrive approximately 2–3 feet landing gear height above the intended landing area with a minimum airspeed for directional control. During the approach the flight instructor directed the student pilot to "utilize throttle manipulation to control the yaw caused by a fixed input on the anti-torque system." The manufactures service letter, SL 19-002 A, states, "During in-flight tail rotor control failure simulation, pilots should never use the twist grip to control yaw." The helicopter sustained substantial damage to the main rotor, fuselage and tail-boom. The flight instructor reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation. The automated weather observation station located on the airport reported that, about the time of the accident, the wind was variable at 4 knots.
Aircraft
- Registration
- N369PA
- Reported as
- Guimbal Cabri (G2)
- Category
- Helicopter
- Serial number
- 1109
- Built
- 2015
- Airframe hours
- 1,839.8
- Engine
- Lycoming O-360-J2A, 145 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Instructional · Part 91
- Operator
- D H Helicopter Inc
- Registered owner
- D H Helicopter Inc
- Airworthiness certificate
- Standard, Normal
- Last inspection
- 100 hour · May 8, 2019
- Departed
- CPS · St Louis, IL
- Destination
- CPS · St. Louis, IL
- Airport
- CPS · St Louis Downtown, runway 30R, 5,301 × 75 ft, concrete
- Equipment
- Electronic multifunction display, Electronic primary flight display, ADS-B
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
- 32
- Injuries
- None
- Certificates
- Flight instructor, Commercial
- Instrument ratings
- Helicopter
- Medical
- Class 2, Without waivers/limitations
- Last flight review
- August 27, 2018
- Seat
- Left
- Flight hours
- 653 total · 425 in this make and model · 545 as pilot in command · 135 in the last 90 days · 32 in the last 30 days · 1 in the last 24 hours
- Role
- Student pilot
- Age
- 27
- Injuries
- None
- Certificate
- Student
- Medical
- Class 2, Without waivers/limitations
- Seat
- Right
- Flight hours
- 62 total · 62 in this make and model · 11 as pilot in command
Weather
- Conditions
- Visual (VMC) · Day
- Visibility
- 10 statute miles
- Temperature
- 79 °F, dew point 70 °F
- Altimeter
- 30.05 inHg
- Observed at
- KCPS
Docket · 3
The files NTSB released with the investigation on July 18, 2019, on NTSB’s docket system: statements, records, photos and specialists’ reports. 1.5 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.