# NTSB CHI89MA046: Boeing 737-201, N242US, Chicago, IL, January 20, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Major investigation · Final report
- Date: January 20, 1989, 07:45 local (13:45 UTC)
- Place: Chicago, IL
- Location: 41.9769° N, 87.9081° W: Placed by OpenAirDocs at CHICAGO O'HARE INTL (ORD), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=41.9769&lon=-87.9081&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 33 uninjured
- Status: Completed, report June 30, 1992
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 14427
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI89MA046
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14427/pdf
- Page: https://openairdocs.org/ntsb/CHI89MA046

## Probable cause

PREVIOUS DAMAGE TO THE AFT CONE (ENGINE MOUNTING) BOLT, WHICH RESULTED IN MISMATCHED SURFACES BETWEEN THE BOLT AND ISOLATION MOUNT, LOSS OF TORQUE DURING CYCLIC LOADING OF THE MOUNTING BOLT, AND SUBSEQUENT FATIGUE FAILURE OF THE BOLT.

## Sequence of events

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

- Airframe/component/system failure/malfunction, takeoff - initial climb
  - engine installation,mounting bolt - other (cause)
  - maintenance,installation - improper, company maintenance personnel (cause)
  - engine installation,mounting bolt - fatigue (cause)
- Engine tearaway, takeoff - initial climb

## Aircraft

- Registration: [N242US](https://openairdocs.org/deregistered/N242US-2007-04-13), registration cancelled 2007-04-13, S/N 22444, built 1981 (OpenAirDocs)
- Reported make and model: BOEING 737-201
- Registry model: [Boeing 737-201](https://openairdocs.org/model/boeing-737-201) (registry code 1384454) (OpenAirDocs)
- Registry engine: [Pratt & Whitney JT8D-9 series](https://openairdocs.org/engine/pratt-whitney-jt8d-9-series) (registry code 52048, turbo-jet) (OpenAirDocs)
- Category: Airplane
- Serial number: 22444
- Airframe hours: 19420
- Engines: P&W JT8D-15 15500 lbs thrust turbo fan
- Damage: Substantial damage
- Flight: Part 121
- Registered owner: Piedmont Airlines
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, November 1, 1989, 569 hours before
- Destination: CLT, CHARLOTTE, NC
- Flight plan: IFR
- Airport: ORD, O'Hare Field, runway 27L, 10,141 × 150 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 37; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 6,105 total, 3,430 in this make and model, 195 in the last 90 days, 65 in the last 30 days, 7 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 350° at 19 knots, gusting 28
- Visibility: 12 statute miles
- Lowest ceiling: 3,200 ft broken
- Temperature: 28 °F, dew point 18 °F
- Altimeter: 30.00 inHg

## 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 19890120001289A](https://openairdocs.org/incident/19890120001289A), Jan 20, 1989: Boeing 737201, Chicago, IL, Substantial damage. Right engine separated from aircraft on climbout. Returned safely. Aft engine cone support bolts failed.

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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