# NTSB CEN09CA156: Rockwell International 500-S, N51RF, Grand Forks, ND, December 5, 2008

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Data collection · Final report
- Date: December 5, 2008, 13:38 local (19:38 UTC)
- Place: Grand Forks, ND
- Coordinates: 47.949165, -97.176109
- Nearby events: https://openairdocs.org/map.md?lat=47.9492&lon=-97.1761&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing: Landing gear not configured](https://openairdocs.org/ntsb-events/095)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report July 28, 2009
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: FAA-Fargo FSDO
- NTSB case key (mKey): 73329
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN09CA156
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/73329/pdf
- Page: https://openairdocs.org/ntsb/CEN09CA156

## Probable cause

The pilot's failure to extend the landing gear prior to touchdown.

## Findings

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

- [Landing gear system](https://openairdocs.org/ntsb-findings/01023200): Aircraft › Aircraft systems · Not used/operated (probable cause); cases with it: [Rockwell International 500-S, 1 case](https://openairdocs.org/ntsb-findings/01023200/cases.md?model=7630410), [All aircraft, 113 cases](https://openairdocs.org/ntsb-findings/01023200/cases.md)
- [Use of equip/info: use of equip/system](https://openairdocs.org/ntsb-findings/02063015): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Rockwell International 500-S, 1 case](https://openairdocs.org/ntsb-findings/02063015/cases.md?model=7630410), [All aircraft, 1,391 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md)

## Sequence of events

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

- [Landing: Landing gear not configured](https://openairdocs.org/ntsb-events/095) (defining event); cases with it: [Rockwell International 500-S, 1 case](https://openairdocs.org/ntsb-events/095/sequence.md?model=7630410), [All aircraft, 584 cases](https://openairdocs.org/ntsb-events/095/sequence.md)

## Analysis

The twin-engine airplane was being operated by the National Oceanic and Atmospheric Administration conducting snow survey flights. The airplane initially departed from the Grand Forks International Airport (GFK), Grand Forks, North Dakota, and made a refueling stop at the Fargo International Airport, Fargo, North Dakota. The airplane was on a repositioning flight back to GFK when the accident occurred. During the flight, the airplane was cleared by air traffic control for the runway 17R localizer backcourse approach to GFK. The airplane landed on runway 17R with the landing gear in the retracted position, resulting in substantial damage to the airplane. Subsequently, the engines were shut down and the aircraft was evacuated. The minimum descent altitude and visibility requirements for the approach were 1,200 feet above mean sea level (msl) and 1 mile respectively. The ceiling and visibility at the time of the accident were 800 feet (about 1,650 feet msl) and 1 mile respectively. The operator noted that there were no mechanical malfunctions.

## Factual narrative

The twin-engine Rockwell AS-500S (Aero Commander) airplane was being operated by the National Oceanic and Atmospheric Administration conducting snow survey flights. The airplane initially departed from the Grand Forks International Airport (GFK), Grand Forks, North Dakota and made a refueling stop at the Fargo International Airport, Fargo, North Dakota. The airplane was on a repositioning flight back to GFK when the accident occurred. During the flight, the airplane was cleared by air traffic control for the runway 17R localizer backcourse approach to GFK. The airplane landed on runway 17R with the landing gear in the retracted position, resulting in substantial damage to the airplane. Subsequently, the engines were shut down and the aircraft was evacuated. The minimum descent altitude and visibility requirements for the approach were 1,200 feet above mean sea level (msl) and 1 mile respectively. The ceiling and visibility at the time of the accident were 800 feet (about 1,650 feet msl) and 1 mile respectively. The operator noted that there were no mechanical malfunctions.

## Aircraft

- Registration: [N51RF](https://openairdocs.org/deregistered/N51RF-2012-11-14), registration cancelled 2012-11-14, S/N 3298, built 1977 (OpenAirDocs)
- Reported make and model: ROCKWELL INTERNATIONAL 500-S
- Registry model: [Rockwell International 500-S](https://openairdocs.org/model/rockwell-international-500-s) (registry code 7630410) (OpenAirDocs)
- Registry engine: [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series) (registry code 41533, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 3298
- Airframe hours: 10586
- Engines: LYCOMING TIO-540 SER 310 horsepower reciprocating; LYCOMING TI0-540 SER 310 horsepower reciprocating
- Damage: Substantial damage
- Flight: Public aircraft - federal, Public use
- Operator: United States Department Of Commerce
- Registered owner: United States Department Of Commerce
- Airworthiness certificate: Standard, Utility; Standard, Normal
- Last inspection: 100 hour, December 3, 2008
- Departed: FAR, Fargo, ND
- Destination: GFK, Grand Forks, ND
- Flight plan: IFR
- Airport: GFK, Grand Forks International Airp, runway 17R, 7,351 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 38; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review June 6, 2008; seat: left; flight hours: 1,096 total, 587 in this make and model
- Co-pilot; age 31; injuries: none; commercial, private; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: right; flight hours: 269 total, 53 in this make and model

## Weather

- Conditions: Instrument (IMC), Day
- Wind: 200° at 12 knots
- Visibility: 1 statute miles
- Lowest ceiling: 800 ft overcast
- Temperature: 21 °F, dew point 18 °F
- Altimeter: 29.57 inHg
- Observed at: GFK

## Other investigations on N51RF (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 CEN11TA279](https://openairdocs.org/ntsb/CEN11TA279), Apr 8, 2011: Rockwell International 500-S (N51RF), Eden Prairie, MN, substantial damage. Probable cause: The pilot's inadequate compensation for the crosswind while landing, which resulted in a loss of directional control.

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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