# NTSB CHI93IA078: Fokker F-28 MK 1000, N452US, Detroit, MI, January 26, 1993

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: January 26, 1993, 09:52 local (14:52 UTC)
- Place: Detroit, MI
- Location: 42.3314° N, 83.0458° W: Placed by OpenAirDocs: center of Detroit, MI, within about 7 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=42.3314&lon=-83.0458&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 42 uninjured
- Status: Completed, report August 26, 1994
- Report: Approved by Office Director
- NTSB case key (mKey): 15594
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI93IA078
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/15594/pdf
- Page: https://openairdocs.org/ntsb/CHI93IA078

## Probable cause

IMPROPER LUBRICATION OF THE HORIZONTAL STABILIZER GEARBOX BY COMPANY MAINTENANCE PERSONNEL. A FACTOR WAS THE MANUFACTURER'S INADEQUATE SERVICE PROCEDURE.

## Sequence of events

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

- Airframe/component/system failure/malfunction, descent - normal
  - fluid - inadequate (cause)
  - maintenance,lubrication - improper, company maintenance personnel (cause)
  - condition(s)/step(s) insufficiently defined, manufacturer (contributing factor)
  - flt control syst,horiz stab drive - deteriorated (cause)
  - flight control,stabilator - movement restricted (cause)

## Analysis

THE CAPTAIN OBTAINED NO RESPONSE TO NOSE-UP STABILIZER TRIM DURING DESCENT. NORMAL NOSE-DOWN TRIM REMAINED OPERABLE; ALTERNATE TRIM WAS NOT ATTEMPTED. THE CREW REPORTED A JAMMED STABILIZER AND LANDED WITH NOSE-DOWN TRIM. DISASSEMBLY OF THE HORIZONTAL STABILIZER CONTROL UNIT SHOWED INADEQUATE LUBRICANT AND EXTENSIVE CORROSION IN A GEARBOX. THE AIRFRAME MANUFACTURER'S PROCEDURE FOR REPLENISHING THE GEARBOX LUBRICANT COULD RESULT IN UNDERSERVICING. THE OPERATOR OBSERVED A GEARBOX SERVICE INTERVAL WHICH WAS 250% OF THE MANUFACTURER'S RECOMMENDATION.

## Aircraft

- Registration: [N452US](https://openairdocs.org/deregistered/N452US-1998-04-22), registration cancelled 1998-04-22, S/N 11105 (OpenAirDocs)
- Reported make and model: FOKKER F-28 MK 1000 (F.28 MK 10)
- Registry model: [Fokker F.28 MK 1000](https://openairdocs.org/model/fokker-f-28-mk-1000) (registry code 4990808) (OpenAirDocs)
- Category: Airplane
- Serial number: 11105
- Airframe hours: 30309
- Engines: Rolls-Royce SPEY 555-15 9850 lbs thrust turbo jet
- Damage: No damage
- Flight: Part 121
- Operator: Usair, doing business as Usair
- Registered owner: Usair
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, March 9, 1992, 1,265 hours before
- Departed: BWI, BALTIMORE, MD
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 50; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 10,900 total, 4,400 in this make and model, 151 in the last 90 days, 85 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 14 knots
- Visibility: 20 statute miles
- Lowest ceiling: 2,000 ft broken
- Temperature: 25 °F, dew point 18 °F
- Altimeter: 30.00 inHg
- Observed at: DTW, 15 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 19930126003649I](https://openairdocs.org/incident/19930126003649I), Jan 26, 1993: Fokker F28MK1000, Detroit, MI. Horizontal stabilizer would move in down position only. Landed safely. Rreplaced stabilizer actuator.

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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