# NTSB CHI91IA297: Boeing 727-224, N88704, Detroit, MI, September 20, 1991

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: September 20, 1991, 18:40 local (22:40 UTC)
- Place: Detroit, MI
- Coordinates: 42.219383, -83.350677 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.2194&lon=-83.3507&mi=10
- Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 136 uninjured
- Status: Completed, report March 31, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 14932
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI91IA297
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14932/pdf
- Page: https://openairdocs.org/ntsb/CHI91IA297

## Probable cause

INADEQUATE MAINTENANCE INSPECTION OF THE MAIN LANDING GEAR ACTUATOR ASSEMBLY BY COMPANY MAINTENANCE PERSONNEL.  A FACTOR IN THE INCIDENT IS INADEQUATE DESIGN OF THE LANDING GEAR ACTUATOR BY THE MANUFACTURER.

## Sequence of events

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

- Airframe/component/system failure/malfunction, takeoff
  - landing gear,normal retraction/extension assembly - jammed
  - remedial action - not possible, pilot in command
  - acft/equip,inadequate design, manufacturer (contributing factor)
  - landing gear,wheel - entangled
  - maintenance,inspection - inadequate, company maintenance personnel (cause)
  - door,landing gear - entangled
- Gear not extended, landing
  - wheels up landing - performed, pilot in command

## Analysis

THE INCIDENT AIRPLANE LANDED WITH THE LEFT MAIN LANDING GEAR PARTIALLY EXTENDED.  THE LANDING GEAR HAD FAILED TO RETRACT PROPERLY AFTER TAKEOFF. THE AIRPLANE REMAINED IN THE AREA OF THE DEPARTURE AIRPORT WHILE THE CREW, IN CONCERT WITH COMPANY MAINTENANCE PERSONNEL AND THE AIRPLANE MANUFACTURER, UNSUCCESSFULLY ATTEMPTED TO TROUBLESHOOT AND RESTORE THE LANDING GEAR TO WORKING ORDER.  THEY LANDED BACK AT THE DEPARTURE AIRPORT WITH CRASH FIRE RESCUE EQUIPMENT STANDING BY.  FIRE TRUCKS APPLIED FOAM TO THE LEFT WING AND WHEEL AREA AFTER THE AIRPLANE STOPPED ON THE RUNWAY. AFTER LANDING THE CREW AND PASSENGERS EXITED THE AIRPLANE USING THE AIRCRAFT AIRSTAIRS.  INSPECTION OF THE LEFT MAIN LANDING GEAR (MLG) REVEALED THE LANDING GEAR TRUCKS HAD BEEN CAPTURED AND SUSPENDED IN AN INTERMEDIATE POSITION BY THE LEFT MAIN GEAR INBOARD DOOR ASSEMBLY. EXAMINATION OF THE MLG DOOR ACTUATOR FITTING SHOWED THE ACTUATOR HAD MOVED TO THE FAR END OF THE AVAILABLE ADJUSTMENT RANGE.

## Aircraft

- Registration: [N88704](https://openairdocs.org/deregistered/N88704-2002-09-17), registration cancelled 2002-09-17, S/N 19513, built 1968 (OpenAirDocs)
- Reported make and model: BOEING 727-224
- Registry model: [Boeing 727-224](https://openairdocs.org/model/boeing-727-224) (registry code 1384076) (OpenAirDocs)
- Registry engine: [Pratt & Whitney JT8D-1](https://openairdocs.org/engine/pratt-whitney-jt8d-1) (registry code 52044, turbo-jet) (OpenAirDocs)
- Category: Airplane
- Serial number: 19513
- Engines: P&W JT8D-9 14500 lbs thrust turbo jet
- Damage: Minor damage
- Flight: Part 121
- Operator: Continental Airlines
- Registered owner: First Security Bank Of Utah
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, July 26, 1991
- Destination: DEN, DENVER, CO
- Flight plan: IFR
- Airport: DTW, Detroit Metro Wayne Co., runway 3, 12,000 × 200 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 57; commercial, 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: 29,000 total, 1,999 in this make and model, 18,000 as pilot in command, 270 in the last 90 days, 80 in the last 30 days, 8 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 350° at 5 knots
- Visibility: 20 statute miles
- Lowest ceiling: 6,000 ft broken
- Temperature: 57 °F
- Altimeter: 30.00 inHg
- Observed at: DTW, 1 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Incident 19910920042029I](https://openairdocs.org/incident/19910920042029I), Sep 20, 1991: Boeing 727224, Detroit, MI, Minor damage. Left main gear would not extend or retract. Aircraft landed runway and left main gear collapsed.

## Other investigations on N88704 (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 LAX87MA125](https://openairdocs.org/ntsb/LAX87MA125), Feb 26, 1987: Boeing 727-224 (N88704), Los Angeles, CA, no damage

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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