# NTSB CHI84IA197: de Havilland DHC-7-102, N708ZW, Battle Creek, MI, May 15, 1984

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: May 15, 1984, 14:10 local (18:10 UTC)
- Place: Battle Creek, MI
- Coordinates: 42.400684, -85.220794 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.4007&lon=-85.2208&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 25 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 12450
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI84IA197
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/12450/pdf
- Page: https://openairdocs.org/ntsb/CHI84IA197

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - flt control syst,rudder trim/tab control - fatigue (cause)

## Analysis

WHILE CRUISING AT 7000 FT MSL, THE 1ST OFFICER WAS TRIMMING THE RUDDER, USING THE ROTARY SWITCH ON THE CENTER CONSOLE, WHEN HE FELT A 'SNAP' INSIDE THE SWITCH. AFTER THAT, THE SWITCH WOULD ROTATE FREELY BETWEEN THE STOPS. THE ACFT BEGAN YAWING LEFT & RIGHT UNTIL THE CREW PULLED THE APPROPRIATE CIRCUIT BREAKER TO DISABLE THE RUDDER TRIM. SUBSEQUENTLY, THEY LANDED WITH FULL RIGHT RUDDER TRIM. AN EXAM REVEALED THAT A CENTERING SPRING, P/N 42M4231137, WHICH LOADS THE SWITCH TO THE NEUTRAL/OFF POSITION HAD FAILED AT A FATIGUE CRACK.

## Aircraft

- Registration: N708ZW (not matched to a registry record)
- Reported make and model: de Havilland DHC-7-102
- Category: Airplane
- Serial number: DHC-7-102
- Engines: P&W PT6A-50 1600 horsepower turbo jet
- Damage: No damage
- Flight: Part 121
- Registered owner: Air Wisconsin, Inc.
- Airworthiness certificate: Standard, Normal
- Departed: MKG, MUSKEGON, MI
- Destination: BTL, BATTLE CREEK, MI
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 34; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, unknown; seat: left; flight hours: 9,592 total, 860 in this make and model, 179 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 15 statute miles
- Lowest ceiling: none

## 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 19840515023869I](https://openairdocs.org/incident/19840515023869I), May 15, 1984: Dhav DHC7102, Battle Creek, MI. Experienced a runaway rudder trim at cruise altitude. Rudder trim switch malfunctioned. Cause undetermined.

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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