# NTSB CHI87IA100: Mcdonnell Douglas DC-9-82, N409AA, Minneapolis, MN, March 23, 1987

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: March 23, 1987, 09:58 local (15:58 UTC)
- Place: Minneapolis, MN
- Coordinates: 44.740962, -93.189323 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=44.7410&lon=-93.1893&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 114 uninjured
- Status: Completed, report July 10, 1989
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 13664
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI87IA100
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/13664/pdf
- Page: https://openairdocs.org/ntsb/CHI87IA100

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, descent - normal
  - turbine assembly,nozzle retention - disintegrated (cause)
  - acft/equip,inadequate design, manufacturer (contributing factor)

## Analysis

THE AIRCRAFT LANDED UNEVENTFULLY AFTER THE RIGHT ENGINE FAILED DURING A DESCENT. THE SHUTDOWN OCCURRED AFTER FAILED ANTIROTATION PINS ALLOWED GAS LOADS TO DRIVE NORMALLY STATIONARY THIRD STAGE VANE CLUSTERS IN THE LOW PRESSURE TURBINE AREA. ROTATION OF THE CLUSTERS IN THEIR CHANNEL ALLOWED THE CLUSTERS TO MACHINE THEMSELVES OUT THROUGH THE LOW PRESSURE TURBINE CASE. EVIDENCE INDICATES THAT 23 OF THE 44 THIRD STAGE VANE ANTI-ROTATION PINS RUPTURED FOLLOWED BY FRACTURE OF THE REMAINING PINS FROM SHEAR OVERLOAD. THE PIN STRESS RUPTURE WAS THE RESULT OF BENDING STRESSES ON THE VANE PINS FROM VANE TWIST & PIN MATERIAL CREEP. A DESIGN TASK WAS INITIATED IN 1986 TO PROVIDE A MORE DURABLE PIN AND IN MAY 1987 P&W RELEASED A NEW MATERIAL, INCO 901 NON-STEPPED, ANTI-ROTATION PIN, PN 803995, TO REPLACE THE PN 599714 TINIDUR PIN.

## Aircraft

- Registration: [N409AA](https://openairdocs.org/deregistered/N409AA-2009-06-25), registration cancelled 2009-06-25, S/N 49320, built 1986 (OpenAirDocs)
- Reported make and model: MCDONNELL DOUGLAS DC-9-82
- Registry model: [Mcdonnell Douglas DC-9-82(MD-82)](https://openairdocs.org/model/mcdonnell-douglas-dc-9-82-md-82) (registry code 3022082) (OpenAirDocs)
- Registry engine: [Pratt & Whitney JT8D series](https://openairdocs.org/engine/pratt-whitney-jt8d-series) (registry code 52053, turbo-jet) (OpenAirDocs)
- Category: Airplane
- Serial number: 49320
- Engines: P&W JT8D-217 20550 lbs thrust turbo fan
- Damage: Minor damage
- Flight: Part 121
- Registered owner: American Airlines Inc.
- Airworthiness certificate: Standard, Transport
- Departed: ORD, CHICAGO, IL
- Destination: MSP, MINNEAPOLIS, MN
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; airline transport, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 7,000 total, 180 in the last 90 days

## Weather

- Conditions: Day
- Wind: 130° at 13 knots
- Visibility: 8 statute miles
- Lowest ceiling: 4,600 ft overcast
- Temperature: 46 °F, dew point 43 °F
- Altimeter: 29.00 inHg
- Observed at: MSP, 30 nm away

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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.