# NTSB CHI90IA106: Nihon YS-11A-600F, N112MP, West Lafayette, IN, April 3, 1990

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: April 3, 1990, 05:45 local (10:45 UTC)
- Place: West Lafayette, IN
- Coordinates: 40.419281, -86.920555 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.4193&lon=-86.9206&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report December 30, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 14567
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI90IA106
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14567/pdf
- Page: https://openairdocs.org/ntsb/CHI90IA106

## Probable cause

AN UNDETECTED ACCUMULATION OF ICE ON THE HORIZONTAL STABILIZER. RELATING FACTORS WERE THE MANUFACTURER'S LACK OF INFORMATION AND AIRCRAFT MANUALS RELATIVE TO THE UNDERSTANDING OF, AND APPROPRIATE PROCEDURES TO PREVENT THE LOSS OF CONTROL.

## Sequence of events

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

- Altitude deviation,uncontrolled, approach - faf/outer marker to threshold (ifr)
  - weather condition - icing conditions
  - anti-ice/deice system - information insufficient
  - information insufficient, manufacturer (contributing factor)
  - horizontal stabilizer surface - ice
  - acft/equip,inadequate aircraft manuals, manufacturer (contributing factor)

## Analysis

THE TRANSPORT CATEGORY AIRCRAFT WAS RETURNING TO THE HOME BASE EMPTY (BALLAST ONLY). WEATHER CONDITIONS EXISTED WHICH WERE CONDUCIVE TO AIRFRAME ICING. ON FINAL APPROACH, WHEN LANDING FLAPS WERE SELECTED, THE AIRCRAFT PITCHED NOSE DOWN ACCOMPANIED BY BUFFETING OF THE AIRFRAME. THE CAPTAIN TOOK CONTROL (FIRST OFFICER HAD BEEN FLYING) AND ADDED FULL POWER. THE FIRST OFFICER SELECTED 15 DEGREES FLAP. THE AIRCRAFT RECOVERED, BUT CONTINUED TO EXHIBIT BUFFETING. THE AIRCRAFT DIVERTED TO AN AIRPORT WITH A LONGER RUNWAY AND A SUCCESSFUL LANDING WAS ACCOMPLISHED. SUBSEQUENT INVESTIGATION REVEALED SUBSTANTIAL ICE ACCUMULATION OUTSIDE THE BOOTED AREA ON THE HORIZONTAL TAIL.

## Aircraft

- Registration: [N112MP](https://openairdocs.org/deregistered/N112MP-2013-04-18), registration cancelled 2013-04-18, S/N 2105, built 1969 (OpenAirDocs)
- Reported make and model: NIHON YS-11A-600F (YS-11A-600)
- Registry model: [Nihon YS-11A-600](https://openairdocs.org/model/nihon-ys-11a-600) (registry code 6310420) (OpenAirDocs)
- Registry engine: [Rolls-Royce DART-542 series](https://openairdocs.org/engine/rolls-royce-dart-542-series) (registry code 54522, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 2105
- Engines: Rolls-Royce DART 542-10J 2750 horsepower turbo prop
- Damage: No damage
- Flight: Part 121
- Registered owner: Mid Pacific Air Corp.
- Departed: YIP, DETROIT, MI
- Flight plan: IFR
- Airport: LAF, Purdue University, runway 10, 6,600 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 29; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; flight hours: 9,677 total, 3,341 in this make and model

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: 350° at 8 knots
- Visibility: 10 statute miles
- Temperature: 34 °F, dew point 28 °F
- Altimeter: 30.00 inHg
- Observed at: LAF

## 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 19900403012689I](https://openairdocs.org/incident/19900403012689I), Apr 3, 1990: Nihon YS11A600, Lafayette, IN. Aircraft buffeting on approach. Control input useless. Recovered and diverted to indianapolis. Two inches ice on tail

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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.