# NTSB CHI86IA115: Boeing 757-251, N508US, Minneapolis, MN, April 3, 1986

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: April 3, 1986, 13:32 local (19:32 UTC)
- Place: Minneapolis, MN
- Coordinates: 44.880756, -93.200523 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=44.8808&lon=-93.2005&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 161 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 13357
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI86IA115
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/13357/pdf
- Page: https://openairdocs.org/ntsb/CHI86IA115

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- On ground/water encounter with terrain/water, landing - flare/touchdown
  - flare - excessive, pilot in command (cause)
  - information insufficient, manufacturer (cause)
  - insufficient standards/requirements,manufacturer, faa(organization) (contributing factor)
  - acft/equip,inadequate handling/perf capabilities, manufacturer (cause)
  - spoiler extension - performed, pilot in command (contributing factor)
  - brakes(normal) - not used, pilot in command (cause)

## Analysis

N508US WAS OPERATING AS NWA FLT 150. THE CAPTAIN STATED AFTER THE INCIDENT THAT THE FLT WAS UNEVENTFUL UNTIL LANDING. UPON LANDING AND SPOILER DEPLOYMENT, THE ACFT PITCHED UP ABRUPTLY, TO AN ATTITUDE OF 10 DEGREES. THE LANDING WAS COMPLETED WITHOUT INCIDENT. EXAMINATION OF THE ACFT REVEALED DAMAGE TO THE ACFT FUSELAGE BELLY. BOEING ISSUED A SERVICE BULLETIN STATING THAT SPOILER DEPLOYMENT ON TOUCHDOWN WOULD PRODUCE A NOSE UP AERODYNAMIC MOMENT. SOLUTIONS TO THIS OCCURRENCE IS A MODIFICATION TO THE SPOILER DEPLOYMENT AND USE OF AUTO BRAKING DURING LANDING.

## Aircraft

- Registration: [N508US](https://openairdocs.org/deregistered/N508US-2011-01-26), registration cancelled 2011-01-26, S/N 23197, built 1985 (OpenAirDocs)
- Reported make and model: BOEING 757-251
- Registry model: [Boeing 757-251](https://openairdocs.org/model/boeing-757-251) (registry code 1384970) (OpenAirDocs)
- Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs)
- Category: Airplane
- Serial number: 23197
- Airframe hours: 1878
- Engines: P&W 2037 37600 lbs thrust turbo fan
- Damage: Minor damage
- Flight: Part 121
- Operator: Northwest Airline
- Registered owner: First Nat'L Bank Boston Truste
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, April 3, 1986
- Departed: SFO, SAN FRANCISCO, CA
- Flight plan: IFR
- Airport: MSP, Minneapolis/St. Paul, runway 11R, 1,000 × 200 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 48; airline transport, flight engineer, commercial; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 200 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 70° at 16 knots
- Visibility: 7 statute miles
- Lowest ceiling: 1,000 ft overcast
- Temperature: 43 °F, dew point 39 °F
- Altimeter: 30.00 inHg
- Observed at: MSP

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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