# NTSB CHI91IA058: Boeing B727-223, N6821, Des Moines, IA, January 4, 1991

- Type: NTSB incident investigation
- Classification: Incident · Minor injuries · Incident investigation · Final report
- Date: January 3, 1991, 19:30 local (Jan 4, 1991, 01:30 UTC)
- Place: Des Moines, IA
- Coordinates: 41.530643, -93.659301 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.5306&lon=-93.6593&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor, 102 uninjured
- Status: Completed, report February 8, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 14924
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI91IA058
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14924/pdf
- Page: https://openairdocs.org/ntsb/CHI91IA058

## Probable cause

AN OIL LEAK ORIGINATING FROM THE AUXILIARY POWER UNIT WHICH CREATED SMOKE IN THE PASSENGER CABIN AFTER IT PASSED THROUGH THE AIR CONDITIONING/HEATING SYSTEM EQUIPMENT AND ASSOCIATED DUCT WORK.

## Sequence of events

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

- Airframe/component/system failure/malfunction, taxi - from landing
  - auxiliary power unit - leak (cause)
  - air cond/heating/pressurization - smoke (cause)
- Miscellaneous/other, standing - engine(s) not operating
  - emergency procedure - performed, pilot in command

## Analysis

THE AIRPLANE WAS TAXIING TO ITS ASSIGNED GATE AFTER LANDING WHEN A FLIGHT ATTENDENT INFORMED THE CAPTAIN THAT THERE WAS A FIRE IN THE REAR OF THE AIRPLANE. THE CAPTAIN IMMEDIATELY STOPPED AND THE PASSENGERS WERE DEPLANNED USING THE COMPANY'S EMERGENCY EVACUATION PROCEDURES. A FLIGHT ATTENDENT AND ONE PASSENGER RECEIVED MINOR INJURIES DURING THE EVACUATION PROCESS. NINETH-SIX PASSENGERS AND SIX OTHER AIRPLANE CREWMEMBERS DID NOT RECEIVE INJURIES. A FIRE WAS NOT PRESENT, SMOKE HAD BEEN FILLING THE PASSENGER CABIN. THE SMOKE CAME FROM THE AIR CONDITIONING/HEATING SYSTEM DUCTS. THE SMOKE WAS A RESULT OF AN OIL LEAK IN THE AIRCRAFT POWER UNIT (APU) WHICH ENTERED THE APU DUCT WORK, THE AIR CONDITIONING PACKS AND ASSOCIATED CIRCULATION DUCTING. WHEN A CERTAIN HEAT RANGE HAD BEEN SELECTED THE OIL LADEN AIR WOULD CHANGE INTO SMOKE AS IT EXITED THE CABIN HEAT DUCT OPENING.

## Aircraft

- Registration: [N6821](https://openairdocs.org/deregistered/N6821-2007-05-19), registration cancelled 2007-05-19, S/N 19496, built 1968 (OpenAirDocs)
- Reported make and model: BOEING B727-223
- Registry model: [Boeing 727-223](https://openairdocs.org/model/boeing-727-223) (registry code 1384074) (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: 19496
- Engines: GE JT-8-D-9 turbo jet
- Damage: No damage
- Flight: Part 121
- Operator: American Airlines, Inc.
- Registered owner: Wilmington Trust Co. - Trustee
- Departed: DFW, DALLAS/FT.WORTH, TX
- Flight plan: IFR
- Airport: DSM, Des Moines International, runway 7

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 37; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, unknown

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: 240° at 5 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F
- Observed at: DSM, 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 19910103001819I](https://openairdocs.org/incident/19910103001819I), Jan 3, 1991: Boeing 727223, Des Moines, IA. Smoke in cabin while taxiing to gate. Stopped and evacuated. Water in oil separator bags caused smoke.

## Other investigations on N6821 (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 NYC79DA041](https://openairdocs.org/ntsb/NYC79DA041), Apr 19, 1979: Boeing 727 (N6821), Philadelphia, PA, substantial 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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