# NTSB MKC87IA043: Embraer EMB-120, N120AM, Springfield, MO, January 23, 1987

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: January 23, 1987, 07:18 local (13:18 UTC)
- Place: Springfield, MO
- Coordinates: 37.280239, -93.290306 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=37.2802&lon=-93.2903&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 10 uninjured
- Status: Completed, report July 10, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 34306
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC87IA043
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/34306/pdf
- Page: https://openairdocs.org/ntsb/MKC87IA043

## Sequence of events

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

- Loss of engine power, landing - roll
  - turbine assembly - output low
  - turbine assembly - undetermined (cause)
  - emergency procedure - performed, pilot in command
  - propeller feathering - performed, pilot in command
  - turbine assembly - overtorque
  - precautionary landing - performed, pilot in command

## Analysis

THE PIC OF THIS AIR MIDWEST FLT 4408 SAID THAT, WHILE ON INITIAL CLIMB, POWER (NP) ON THE LEFT ENGINE DECAYED TO 60% AND WOULD NOT RECOVER. THE ENGINE WAS FEATHERED BY CONDITION LEVER BUT THE TORQUE ROSE TO 140% WHILE RETURNING FOR A LANDING, ACCORDING TO THE PIC. THE AIRCRAFT LANDED SAFELY. A POST-INCIDENT INVESTIGATION DISCLOSED THAT AN OIL LEAK HAD BEEN TRACED, THE DAY PRIOR TO THE INCIDENT, TO A FRACTURED PROPELLER CONTROL UNIT SOLENOID. THAT PART WAS REMOVED AND REPLACED AS A PRECAUTIONARY MEASURE. THE PLASTIC BLADE RETAINING RINGS INSIDE THE PROPELLER ASSY WERE DAMAGED DUE TO THE ENGINE OVERTORQUE AND SUBSEQUENT SHUTDOWN. A TEARDOWN OF THE PROPELLER CONTROL UNIT (PCU) SHOWED THAT THE BETA TUBE HAD NOT FAILED NOR WAS IT FREEWHEELING INSIDE THE PCU. A SPECTROGRAPHIC ANALYSIS OF OIL SAMPLES, DRAWN FROM FOUR SEPARATE SECTIONS OF THE ENGINE, TESTED SATIFACTORILY. AS SUCH, NO REASON COULD BE FOUND FOR THE DROP IN ENGINE POWER (NP) AND SUBSEQUENT OVERTORQUE.

## Aircraft

- Registration: [N120AM](https://openairdocs.org/deregistered/N120AM-2002-10-24), registration cancelled 2002-10-24, S/N 120.012, built 1986 (OpenAirDocs)
- Reported make and model: EMBRAER EMB-120
- Registry model: [Embraer EMB-120ER](https://openairdocs.org/model/embraer-emb-120er) (registry code 3260203) (OpenAirDocs)
- Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs)
- Category: Airplane
- Serial number: 120.012
- Engines: P&W PW115 1600 horsepower turbo prop
- Damage: Minor damage
- Flight: Part 135
- Registered owner: Air Midwest, Inc.
- Airworthiness certificate: Standard, Transport
- Departed: SGF, SPRINGFIELD, MO
- Destination: BNA, NASHVILLE, TN
- Flight plan: IFR
- Airport: SGF, Springfield Regional, runway 1, 7,003 × 150 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; flight engineer, airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 9,150 total, 8,850 as pilot in command

## Weather

- Conditions: Visual (VMC), Dawn
- Wind: 350° at 8 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 36 °F, dew point 19 °F
- Altimeter: 30.00 inHg
- Observed at: SGF, 8 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 19870123003179I](https://openairdocs.org/incident/19870123003179I), Jan 23, 1987: Emb EMB120, Springfield, MO. The engine torque exceeded limits during climbout and the pilot secured it. The aircraft safely returned to landing

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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