# NTSB DEN90IA189: Boeing 737-222, N9044U, Denver, CO, September 19, 1990

- Type: NTSB incident investigation
- Classification: Incident · Minor injuries · Incident investigation · Final report
- Date: September 19, 1990, 11:00 local (17:00 UTC)
- Place: Denver, CO
- Coordinates: 39.729267, -105.020217 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.7293&lon=-105.0202&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor, 94 uninjured
- Status: Completed, report May 10, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 17853
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN90IA189
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17853/pdf
- Page: https://openairdocs.org/ntsb/DEN90IA189

## Probable cause

THE FAILURE OF THE FLIGHT CREW TO FOLLOW EMERGENCY PROCEDURES/DIRECTIVES. FACTORS WERE THE FAILURE OF THE AIRCRAFT ELECTRICAL SYSTEM (RELAYS) AND THE FAILURE OF THE COMPANY TO PROVIDE A JETWAY OPERATOR.

## Sequence of events

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

- Airframe/component/system failure/malfunction, taxi - to takeoff
  - door,inspection - open (contributing factor)
  - procedures/directives - improper, pilot in command (cause)
  - electrical system,electric relay - failure,total (contributing factor)
  - evacuation - performed, pilot in command
  - evacuation - unavailable, company/operator management (contributing factor)

## Analysis

SHORTLY AFTER PUSHBACK IT WAS NOTICED THAT THE #2 ENG DOOR 2 RIGHT HANDLE WAS NOT FLUSH. THE ENG WAS SHUT DOWN AND GROUND MAINT PERSONNEL CLOSED THE DOOR FROM THE OUTSIDE. THE CABIN THEN BEGAN TO FILL WITH DENSE SMOKE. THE CAPTAIN, USING RADIO AND AN OPEN WINDOW, WAS UNSUCCESSFUL IN GETTING A JETWAY TO THE AIRPLANE, AND THE CREW AND PAX EXITED USING SLIDES. IT WAS LATER DETERMINED THAT THE BATTERY BUSS RELAY (R1) AND BATTERY TRANSFER RELAY (R2) HAD FAILED. THE AIRPLANE HAD BEEN PUSHED BACK AT GATE B-8, AND HAD RECEIVED CLEARANCE TO GATE B-20 FOR THE EVACUATION. THERE WAS NO JETWAY OPERATOR PRESENT, AND GROUND PERSONNEL ARE NOT CROSS-TRAINED TO OPERATE A JETWAY. WHEN THE #2 ENG WAS SHUT DOWN, THE ELECTRICAL TRANSFER SYSTEM PICKED UP THE LOAD. THE FLIGHTCREW DID NOT POWER THE RIGHT BUS FROM THE APU.

## Aircraft

- Registration: [N9044U](https://openairdocs.org/deregistered/N9044U-2013-06-14), registration cancelled 2013-06-14, S/N 19550, built 1968 (OpenAirDocs)
- Reported make and model: BOEING 737-222
- Registry model: [Boeing 737-222](https://openairdocs.org/model/boeing-737-222) (registry code 1384473) (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: 19550
- Engines: P&W 14000 lbs thrust turbo jet
- Damage: No damage
- Flight: Part 121
- Operator: United Airlines
- Destination: ICT, WICHITA, KS
- Flight plan: IFR
- Airport: DEN, Stapleton Intl

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 51; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; flight hours: 17,500 total, 1,119 in this make and model, 10,000 as pilot in command, 123 in the last 90 days, 13 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 30° at 5 knots
- Visibility: 7 statute miles
- Lowest ceiling: none
- Temperature: 75 °F, dew point -0 °F

## 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 19900919041989I](https://openairdocs.org/incident/19900919041989I), Sep 19, 1990: Boeing 737222, Denver, CO. Shut down engine to store aft service door handle. Mismanged electrical power. Air conditioning pack overheated.

## Other investigations on N9044U (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 MIA74IM090](https://openairdocs.org/ntsb/MIA74IM090), May 5, 1974: Boeing 737 (N9044U), Birmingham, AL, incident, minor 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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