CEN11CA403

NTSB accident investigation · Bell 47G-4A · Montgomery City, MO · June 18, 2011

Accident · No injuriesData collectionFinal report
Date
June 18, 2011, 18:45 local (23:45 UTC)
Place
Montgomery City, MO
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N24HMBell 47G-4A
Defining event
Landing: Hard landing
Weather
Visual (VMC) · Day
Status
Completed · report October 4, 2011
Report
Approved by Office Director
NTSB office
Central Region
FAA report
20110618012569A
Case key
80823

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

A loss of control during the precautionary landing, which resulted in inadvertent contact between the main rotor and the tailboom. Contributing to the accident was the overloaded condition.

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.

Use of equip/info: aircraft controlPersonnel issues › Task performance · PilotBell 47G-4A: 2 casesAll aircraft: 9,295 casesProbable cause
Aircraft capability: maximum weightAircraft › Aircraft oper/perf/capability · Capability exceededBell 47G-4A: 1 caseAll aircraft: 152 cases

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 pilot reported that he had returned from an agricultural application to reload the cleaning solution. Unbeknownst to the pilot, the helicopter was loaded with approximately 90 gallons of solution, instead of the expected 70 gallons for the flight. The pilot reported that he increased engine power and lifted off; however, immediately after lift off the engine and rotor speed began to decrease. He selected a suitable landing point and flared for touchdown about 10 feet above ground level to minimize the forward speed. The helicopter touched down on the rear portion of the landing skids and began to pitch forward. He applied aft cyclic control to prevent the helicopter from nosing over. He subsequently heard a bang and observed debris coming from the aircraft. He shut down the engine and secured the helicopter. A postaccident examination revealed that the main rotor had struck the tailboom resulting in substantial damage to the airframe. The pilot said the helicopter may have been on a slight incline when the solution was loaded, allowing the right side tank to fill more than the left side tank. He was unaware of the overload condition. The pilot added that closer monitoring of the helicopter and chemical truck incline, and the final amount of solution being loaded onto the helicopter, might have prevented the accident. The pilot did not report any failures or malfunctions that would have precluded normal operation.

Factual narrative

The pilot reported that he had returned from a prior agricultural application flight. The helicopter chemical tank was loaded with cleaning solution. The pilot stated that he increased engine power and lifted off again. However, immediately after takeoff, the engine and rotor speed began to decrease, and the pilot selected a nearby location for a landing. He flared for touchdown about 10 feet above ground level in order to minimize the forward speed. The helicopter touched down on the rear portion of the landing skids and began to pitch forward. The pilot responded by applying aft cyclic control to prevent the helicopter from nosing over. He subsequently heard a bang and observed debris coming from the aircraft. He shut down the engine and secured the helicopter. A postaccident examination revealed that the main rotor had struck the tailboom resulting in substantial damage to the airframe. The pilot did not report any failures or malfunctions related to the helicopter that occurred prior to the accident. However, the chemical tank was determined to have been loaded with approximately 90 gallons of cleaning solution, instead of the intended 70 gallons. He commented that the aircraft may have been on a slight incline when the solution was loaded, allowing the right side tank to fill more than the left side tank. As a result, he was unaware of the overload condition. The pilot added that closer monitoring of the helicopter and chemical truck incline, and the final amount of solution being loaded onto the helicopter, might have prevented the accident.

Aircraft

Registration
N24HM
Reported as
Bell 47G-4A
Category
Helicopter
Serial number
7688
Airframe hours
11,153
Engine
Lycoming VO-540 SERIES, 310 horsepower, reciprocating
Damage
Substantial damage
Flight
Aerial application · Part 137
Operator
Rhineland Grain Inc
Registered owner
Rhineland Grain Inc
Airworthiness certificate
Special, Restricted (Special)
Last inspection
Annual · February 26, 2011
Departed
PVT · Montgomery City, MO
Destination
PVT · Montgomery City, MO

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

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
27
Injuries
None
Certificates
Flight instructor, Commercial
Instrument ratings
Helicopter
Medical
Class 2, Without waivers/limitations
Last flight review
March 31, 2011
Seat
Left
Flight hours
1,900 total · 880 in this make and model · 1,810 as pilot in command · 55 in the last 90 days · 40 in the last 30 days · 3 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
180° at 5 knots
Visibility
10 statute miles
Lowest ceiling
None

Docket · 2

The files NTSB released with the investigation on July 21, 2011, on NTSB’s docket system: statements, records, photos and specialists’ reports. 444 KB 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.

Other investigations on N24HM · 1

Matched to the same aircraft by N-number and date.