# NTSB CHI88FA223: Boeing 727-31, N852TW, Chicago, IL, August 27, 1988

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Field investigation · Final report
- Date: August 27, 1988, 16:50 local (21:50 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: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 7 minor, 61 uninjured
- Status: Completed, report July 9, 1990
- Report: Approved by Office Director
- NTSB case key (mKey): 13968
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI88FA223
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/13968/pdf
- Page: https://openairdocs.org/ntsb/CHI88FA223

## Probable cause

IMPROPER PROCEDURAL CHECKLIST IN WHICH A CRITICAL STEP WAS NOT LISTED.

## Sequence of events

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

- Airframe/component/system failure/malfunction, approach - faf/outer marker to threshold (ifr)
  - landing gear,normal retraction/extension assembly - inoperative
  - missed approach - performed (cause)
  - checklist - inaccurate, company/operator management (contributing factor)
  - procedures/directives - improper, company/operator management (cause)
  - condition(s)/step(s) not listed, faa(principal maintenance inspector) (cause)
- Gear not extended, landing
  - wheels up landing - performed, pilot in command

## Analysis

SCHEDULED DOMESTIC PART 121 FLIGHT COULD NOT GET LANDING GEAR TO EXTEND ON APPROACH TO CHICAGO MIDWAY AIRPORT. AFTER MISSED APPROACH, CREW TRIED UNSUCCESSFULLY TO EXTEND GEAR MANUALLY USING PROCEDURES IN COCKPIT CHECKLIST AND FLIGHT OPERATIONS MANUAL. EMERGENCY GEAR-UP LANDING WAS MADE AT CHICAGO O'HARE INTERNATIONAL AIRPORT. INVESTIGATION REVEALED A DISCONNECTED GEAR SELECTOR ACTUATING ROD FROM THE NORMAL LANDING GEAR RETRACT/EXTENSION ACTUATING ASSEMBLY. CREW DAMAGED MANUAL GEAR EXTENSION MECHANISM IN MANUAL EXTENSION ATTEMPTS. FAA APPROVED PROCEDURAL CHECKLIST HAD OMITTED CRITICAL STEP IN MANUAL GEAR EXTENSION PROCEDURE.

## Aircraft

- Registration: [N852TW](https://openairdocs.org/deregistered/N852TW-1988-10-20), registration cancelled 1988-10-20, S/N 18571 (OpenAirDocs)
- Reported make and model: BOEING 727-31
- Registry model: [Boeing 727-31](https://openairdocs.org/model/boeing-727-31) (registry code 1384010) (OpenAirDocs)
- Category: Airplane
- Serial number: 18571
- Airframe hours: 56099
- Engines: P&W JT8D-7B 14000 lbs thrust turbo fan
- Damage: Substantial damage
- Flight: Part 121
- Operator: Trans World Airlines, doing business as Trans World Airlines
- Registered owner: Trans World Airlines, Inc
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, April 29, 1988, 720 hours before
- Departed: STL, ST. LOUIS, MO
- Destination: MDW, CHICAGO, IL
- Flight plan: IFR
- Airport: ORD, Chicago O'Hare, runway 14L, 10,003 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 51; 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: 16,899 total, 6,411 in this make and model, 5,266 as pilot in command, 195 in the last 90 days, 76 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 210° at 9 knots
- Visibility: 5 statute miles
- Lowest ceiling: 1,400 ft broken
- Temperature: 61 °F, dew point 61 °F
- Altimeter: 29.00 inHg
- Observed at: ORD, 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).

- [Accident 19880827071829A](https://openairdocs.org/incident/19880827071829A), Aug 27, 1988: Boeing 72731, Chicago, IL, Substantial damage. Unable gear at airport. Landed gear up at alternate. Disconnected gear selector rod. Crew damaged manual gear.

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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