# NTSB CEN11LA182: Cessna 150L, N6622G, Trenton, MI, February 12, 2011

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: February 12, 2011, 11:50 local (16:50 UTC)
- Place: Trenton, MI
- Coordinates: 42.098888, -83.161392 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.0989&lon=-83.1614&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Defining event: [Maneuvering: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report July 18, 2013
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 78342
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11LA182
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/78342/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=78342
- Page: https://openairdocs.org/ntsb/CEN11LA182

## Probable cause

The loss of preload torque on a connecting rod nut and bolt, which precipitated a separation of the connecting rod from the engine's crankshaft and resulted in the total loss of engine power.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Cessna 150L, 6 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=2071826), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md)
- [Maintenance/inspections](https://openairdocs.org/ntsb-findings/01010500): Aircraft › Aircraft handling/service · Incorrect service/maintenance; cases with it: [Cessna 150L, 1 case](https://openairdocs.org/ntsb-findings/01010500/cases.md?model=2071826), [All aircraft, 103 cases](https://openairdocs.org/ntsb-findings/01010500/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Cessna 150L, 1 case](https://openairdocs.org/ntsb-events/040/sequence.md?model=2071826), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md)
- [Maneuvering: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Cessna 150L, 19 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2071826), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 150L, 18 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2071826), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)

## Analysis

The pilot had been conducting a banner towing operation for about 55 minutes when he felt a heavy vibration and heard a “loud bang.” The airplane's engine subsequently lost power, and the pilot executed a forced landing. During the forced landing, the nose landing gear collapsed when it contacted "heavy snow and unimproved terrain," resulting in substantial damage to the firewall. A postaccident examination of the engine revealed that one of the connecting rods had separated from the crankshaft. Metallurgical examination determined that one of the two connecting rod bolts had failed in overstress. The second connecting rod bolt was deformed but otherwise intact; its associated nut had separated from the bolt and was undamaged. The lack of damage to one of the connecting rod nuts in conjunction with the overstress failure of the opposing bolt was consistent with a loss of installation torque on the intact nut. The engine had accumulated 2,836 hours since overhaul. The operator did not supply engine overhaul maintenance records but provided a statement indicating that the installed bolts and nuts were new at the engine cylinder's last maintenance (an engine manufacturer service bulletin instructs that connecting rod bolts and nuts be replaced any time they are removed). However, due to the lack of maintenance records and the number of hours since last overhaul, the investigation could not conclusively attribute the loss of preload torque to the overhaul operation.

## Factual narrative

On February 12, 2011, about 1150, eastern standard time, a Cessna 150L airplane, N6622G, was substantially damaged during a forced landing near Trenton, Michigan, following an in-flight loss of engine power. The commercial pilot, the sole occupant on board the airplane, reported no injuries. The airplane was registered to and operated by Drake Aerial Enterprises, LLC under the provisions of 14 Code of Federal Regulations Part 91 as a banner towing flight. Visual flight rules (VFR) conditions prevailed for the flight, which was not operating on a flight plan. The local flight departed from the Oakland/Troy Airport, near Troy, Michigan, about 1100, and was destined for the Grosse Ile Municipal Airport, near Grosse Ile, Michigan. The operator's accident report stated that the pilot was flying the airplane with a banner in tow for about 55 minutes when the pilot felt a heavy vibration and heard a loud bang. The airplane "instantly" lost power and the pilot was unable to "keep the engine running." He released the banner over an area away from people and structures and performed a forced landing. During the forced landing the nose landing gear collapsed when it contacted "heavy snow and unimproved terrain." Substantial damage occurred when the collapsed nose landing gear bent the firewall. The airplane was a 1970 Cessna 150L, serial number 15072122, was an all-metal, high-wing, semimonocoque design airplane. The airplane was powered by a Lycoming O-360-A4A, serial number L-28947-35A, installed under supplemental type certificate SA4795SW. The installation was documented on a major repair and alteration form, dated December 8, 2003. The airplane was maintained under an annual inspection program and the operator reported that the airplane’s most recent annual inspection was conducted on February 7, 2010. The airplane reportedly accumulated 8,201 hours of total time and the engine accumulated 2,836 hours since overhaul A postaccident examination of the engine revealed that the no. four connecting rod had separated from its crankshaft. One of the two corresponding connecting rod bolts was deformed. However, the associated nut had separated from the bolt and appeared undamaged. The second connecting rod bolt was fractured near the midpoint of the shank. Metallurgical examination of the fracture surface revealed features consistent with overstress separation. The Lycoming Service Bulletin No. 240W, Mandatory Parts Replacement at Overhaul and During Repair or Maintenance, in part, stated: AT OVERHAUL OR UPON REMOVAL: ... Any time the following parts are removed from any Lycoming reciprocating engine, it is mandatory that the following parts be replaced regardless of their apparent condition: ... Stressed bolts and fasteners, such as: ... Connecting rod bolts and nuts The operator indicated that the installed connecting rod bolts and nuts were new when the last maintenance was performed on this cylinder.

## Aircraft

- Registration: [N6622G](https://openairdocs.org/aircraft/N6622G), registered now, S/N 15072122 (OpenAirDocs)
- Reported make and model: CESSNA 150L
- Registry model: [Cessna 150L](https://openairdocs.org/model/cessna-150l) (registry code 2071826) (OpenAirDocs)
- Registry engine: [Continental 0-200 series](https://openairdocs.org/engine/continental-0-200-series) (registry code 17020, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 15072122
- Airframe hours: 8201
- Engines: Lycoming O-360-A4A 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Banner tow, Part 91
- Operator: Drake Aerial Enterprises LLC DBA
- Registered owner: Drake Aerial Enterprises LLC DBA
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, February 7, 2010
- Departed: VLL, Troy, MI
- Destination: ONZ, Grosse Ile, MI

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; injuries: none; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review November 15, 2010; seat: left; flight hours: 2,200 total, 800 in this make and model, 2,100 as pilot in command, 20 in the last 90 days, 12 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 270° at 15 knots, gusting 21
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 30 °F, dew point 14 °F
- Altimeter: 30.03 inHg
- Observed at: DTW, 9 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 20110212004189A](https://openairdocs.org/incident/20110212004189A), Feb 12, 2011: Cessna 150L, Trenton, MI, Substantial damage. On 2/12/2011 pilot had been flying from troy airport to grossile airport, towing a banner, for approximately 55 minutes in level flight when he felt a heavy…

## Other investigations on N6622G (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB CEN16LA236](https://openairdocs.org/ntsb/CEN16LA236), Jun 28, 2016: Cessna 150L (N6622G), Detroit, MI, substantial damage, 1 fatal. Probable cause: The pilot’s disregard of the banner-tow operator's policy regarding the maximum allowable flight duration, which resulted in a total loss of engine power due to fuel exhaustion.

## Docket (4 files)

The files NTSB released with the investigation on May 9, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=78342. 1.9 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 963 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356612&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Materials Laboratory Factual Report No. 13-006 (item 2, .PDF, 726 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40386349&FileExtension=.PDF&FileName=Materials%20Laboratory%20Factual%20Report%20No.%2013-006-Master.PDF
- Miscellaneous - Lycoming Service Bulletin 240W (item 3, .PDF, 184 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40386473&FileExtension=.PDF&FileName=Miscellaneous%20-%20Lycoming%20Service%20Bulletin%20240W-Redacted.PDF
- Miscellaneous - Operator Statement on Rod Bolts (item 4, .PDF, 56 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40386482&FileExtension=.PDF&FileName=Miscellaneous%20-%20Operator%20Statement%20on%20Rod%20Bolts-Master.PDF

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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