# NTSB ERA18LA067: Cessna 172RG, N9415B, Martinsburg, WV, January 21, 2018

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: January 21, 2018, 13:04 local (18:04 UTC)
- Place: Martinsburg, WV
- Coordinates: 39.402221, -77.983055 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.4022&lon=-77.9831&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Defining event: [Approach-VFR pattern downwind: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report May 29, 2019
- Report: Approved by Office Director
- NTSB office: Eastern Region Aviation
- Parties: FAA/FSDO
- NTSB case key (mKey): 96648
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA18LA067
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/96648/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=96648
- Page: https://openairdocs.org/ntsb/ERA18LA067

## Probable cause

A hydraulic leak in the right main landing gear actuator, which resulted in the main landing gear not extending.

## Findings

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

- [Hydraulic power system: hydraulic, main system](https://openairdocs.org/ntsb-findings/01022910): Aircraft › Aircraft systems · Damaged/degraded (probable cause); cases with it: [Cessna 172RG, 1 case](https://openairdocs.org/ntsb-findings/01022910/cases.md?model=2072438), [All aircraft, 27 cases](https://openairdocs.org/ntsb-findings/01022910/cases.md)
- [Fluids: hydraulic fluid](https://openairdocs.org/ntsb-findings/01071015): Aircraft › Fluids/misc hardware · Fluid level (probable cause); cases with it: [Cessna 172RG, 3 cases](https://openairdocs.org/ntsb-findings/01071015/cases.md?model=2072438), [All aircraft, 33 cases](https://openairdocs.org/ntsb-findings/01071015/cases.md)
- [Landing gear system: main landing gear](https://openairdocs.org/ntsb-findings/01023210): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Cessna 172RG, 4 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=2072438), [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md)

## Sequence of events

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

- [Approach-VFR pattern downwind: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Cessna 172RG, 11 cases](https://openairdocs.org/ntsb-events/330/sequence.md?model=2072438), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md)
- [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Cessna 172RG, 11 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2072438), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md)

## Analysis

The flight instructor stated that he and the private pilot were about to make their seventh landing, but when the pilot extended the gear, the gear down-and-locked light did not illuminate. A visual check revealed that the nose gear was extended but the main gear was not fully extended. The flight instructor used the emergency gear handle to try and pump the main gear down, but there was insufficient hydraulic pressure in the system. The flight instructor landed the airplane with the nosewheel extended, but the airplane’s left wing dropped, which resulted in substantial damage to the left wing and the elevator. After exiting the airplane, hydraulic fluid was observed pooling under the airplane and along the side of the empennage. Postaccident examination of the airplane revealed that an O-ring inside the right gear actuator failed and was leaking hydraulic fluid. Because the landing gear is extended/retracted by hydraulic pressure, the leak likely prevented the system from having adequate pressure for the electric pump and the manual gear handle to extend the gear.

## Factual narrative

On January 21, 2018, at 1304 eastern standard time, a Cessna 172RG airplane, N9415B, sustained substantial damage while landing at the Eastern West Virginia Regional Airport (MRB), Martinsburg, West Virginia. The flight instructor and the private pilot were not injured. The airplane was registered to Dulles Aviation, Manassas, Virginia, and operated by Av-Ed Flight School, Leesburg, Virginia, as a Title 14 Code of Federal Regulations Part 91 instructional flight. Visual meteorological conditions prevailed and no flight plan was filed for the flight that originated from Leesburg Executive Airport (JYO), Leesburg, Virginia, about 1130. The flight instructor stated that the purpose of the flight was to practice commercial pilot maneuvers and landings. The flight was normal, and they had completed about six short and soft-field takeoffs and landings without incident. On the seventh landing, after the private pilot extended the landing gear, the gear down-and-locked light did not illuminate. A visual check revealed that the nose gear was extended but the main gear was trailing and not fully extended. The flight instructor said they used the manual emergency gear handle to try and pump the main gear down, but there was not enough hydraulic pressure in the system to extend the gear. The flight instructor then landed the airplane with the nose wheel still extended. He said he was able to keep the airplane straight for about 600 ft, but the airplane's left wing dropped resulting in substantial damage to the wing and elevator. After exiting the airplane, hydraulic fluid was observed pooling under the airplane and along the side of the empennage. The hydraulic reservoir was empty. A postaccident examination of the airplane revealed that an O-ring had failed internally inside the right gear actuator and it was leaking hydraulic fluid. Since the landing gear is extended/retracted by hydraulic pressure, the leak prevented the system from having adequate pressure for the electric pump and the manual gear handle to extend the gear. At 1306, the weather conditions reported at MRB were calm wind, visibility 10 statute miles, scattered clouds at 3,900 ft, overcast clouds at 7,500 ft, temperature 13° C, dewpoint 5° C, and an altimeter setting of 30.12 inches of mercury.

## Aircraft

- Registration: [N9415B](https://openairdocs.org/aircraft/N9415B), registered now, S/N 172RG0816, built 1981 (OpenAirDocs)
- Reported make and model: CESSNA 172RG
- Registry model: [Cessna 172RG](https://openairdocs.org/model/cessna-172rg) (registry code 2072438) (OpenAirDocs)
- Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 172RG0816
- Year built: 1981
- Airframe hours: 3054.8
- Engines: LYCOMING O-360 F 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, June 22, 2017
- Departed: MRB, Martinsburg, WV
- Destination: MRB, Martinsburg, WV
- Airport: MRB, Eastern West Virginia Regional, runway 26, 8,815 × 150 ft, asphalt
- Equipment: Stall warning system

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Flight instructor; age 51; injuries: none; commercial, private, flight instructor; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; seat: right; restraint: 3-point; flight hours: 4,056 total, 18 in this make and model, 1,919 as pilot in command, 17 in the last 90 days, 3 in the last 30 days, 1.6 in the last 24 hours
- Pilot; age 57; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; seat: left; restraint: 3-point

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: 7,500 ft overcast
- Temperature: 55 °F, dew point 41 °F
- Altimeter: 30.12 inHg
- Observed at: MRB

## 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 20180121001089A](https://openairdocs.org/incident/20180121001089A), Jan 21, 2018: Cessna 172RG, Martinsburg, WV, Substantial damage. Pilot attempted to land at mrb, gear failed to extend after multiple attempts. The nose landing gear did extend but the main landing gear did not. Weather -…

## Docket (4 files)

The files NTSB released with the investigation on February 8, 2019, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=96648. 11.8 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 10.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40470216&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF
- Summary of Email - Aero Engines and Page from Parts Catalog (item 2, .PDF, 249 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40470217&FileExtension=.PDF&FileName=Summary%20of%20Email%20-%20Aero%20Engines%20and%20Page%20from%20Parts%20Catalog-Master.PDF
- Maintenance Records (item 3, .PDF, 510 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40470218&FileExtension=.PDF&FileName=Maintenance%20Records-Master.PDF
- Photos (item 4, .PDF, 4 photos, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40470219&FileExtension=.PDF&FileName=Photos-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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