CEN23LA150

NTSB accident investigation · Helicopteres Guimbal Cabri G2 · Cahokia, IL · April 9, 2023

Accident · Minor injuriesClass 3 · LimitedFinal report
Date
April 9, 2023, 08:45 local (13:45 UTC)
Place
Cahokia, IL
Injuries
1 minor, 1 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N372PAHelicopteres Guimbal Cabri G2
Defining event
Landing-flare/touchdown: Sys/Comp malf/fail (non-power)
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Central Region
Parties
Federal Aviation Administration, St. Louis FSDO, Bureau d'Enquêtes et d'Analyses pour la sécurité de l'aviation civile
FAA report
20230409008059A
Case key
107038

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 lack of proper attachment of the cyclic control that resulted in a loss of control during a landing approach and impact with terrain. Contributing to the accident was the improper maintenance performed.

Findings · 1

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.

Flight control systemAircraft › Aircraft systems · Not specifiedHelicopteres Guimbal CABRI G2: 1 caseAll aircraft: 65 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

The flight instructor stated that during an instructional flight he lost left cyclic control during an approach for landing. The student pilot’s right cyclic controls continued to function, and the flight instructor coached him on cyclic control inputs to maintain control of the helicopter. The student’s cyclic control became unresponsive to control inputs during the attempted landing and the helicopter impacted the ground resulting in substantial damage to the main rotor blades. Postaccident examination of the flight control system revealed that retaining hardware for the pins used to attach the left cyclic control were not installed. Maintenance personnel were unable to provided information regarding previous maintenance performed on the cyclic controls. The left cyclic control did not have any deformation/damage.

Factual narrative

On April 9, 2023, at 0845 central daylight time, a Helicopteres Guimbal Cabri G2, N372PA, was involved in an accident near Cahokia, Illinois. The helicopter sustained substantial damage. The flight instructor received minor injuries and the student pilot was uninjured. The helicopter was operated under Title 14 Code of Federal Regulations Part 91 as an instructional flight. The flight instructor stated that during the approach for landing at the departure airport, his left cyclic had “a little bit of play,” and the helicopter was not responding fully to his control inputs. He then completely lost cyclic control upon lining up with the taxiway of intended landing site. He stated that he still had collective and rudder control. The student pilot’s cyclic controls continued to function, and the flight instructor coached him on cyclic control inputs to maintain control of the helicopter, but the student pilot’s cyclic control then ceased to function. The helicopter impacted the ground during the attempted landing and sustained substantial damage to the main rotor blades. Postaccident examination of the flight control system revealed that the helicopter’s Illustrated Parts Catalog part #34 (Reference HG17-0545) - Pin and part #36 (Reference HG21-0803) – Safety Pin were found not inplace on the left cyclic control. Part #43.0 (Reference G41-41-300) – Pin Locker, part # 44 (Reference HG20-2036) – Bolt and part #7 (Reference HG12-0332) – Nut were not installed. Ideal Aviation was unable to a date when these parts were removed. There was no evidence indicating these parts were impacted by the crash. The left cyclic control did not have any deformation/damage.

Aircraft

Registration
N372PA
Reported as
Helicopteres Guimbal Cabri G2
Category
Helicopter
Serial number
1150
Built
2016
Engine
Lycoming O-360, 145 horsepower, reciprocating
Damage
Substantial damage
Flight
Instructional · Part 91
Operator
Ideal Aviation
Registered owner
Rotor Leasing LLC
Airworthiness certificate
Standard, Normal
Last inspection
Annual · April 7, 2023
Destination
Same as departure
Airport
CPS · St Louis Downtown Airport, runway Taxiway A, 2,000 × 50 ft, concrete
Equipment
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
27
Injuries
Minor
Certificates
Flight instructor, Private, Commercial
Instrument ratings
Helicopter
Medical
Class 2, Without waivers/limitations
Last flight review
June 5, 2022
Seat
Left
Restraint
4-point
Flight hours
545 total · 542 in this make and model · 483 as pilot in command · 87 in the last 90 days · 40 in the last 30 days · 3 in the last 24 hours
Role
Student pilot
Age
41
Injuries
None
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 2, Without waivers/limitations
Last flight review
July 2, 2010
Seat
Right
Restraint
4-point
Flight hours
131 total · 17 in this make and model · 34 as pilot in command · 17 in the last 90 days · 9 in the last 30 days · 0 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
130° at 8 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
52 °F, dew point 30 °F
Altimeter
30.40 inHg
Observed at
CPS

Docket · 6

The files NTSB released with the investigation on July 10, 2024, on NTSB’s docket system: statements, records, photos and specialists’ reports.

FAA reports on this event · 1

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