# NTSB CHI88DEC02: Chappel Ratsrepus 300, N889HC, Pontiac, MI, May 25, 1988

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: May 25, 1988, 15:07 local (19:07 UTC)
- Place: Pontiac, MI
- Location: 42.6656° N, 83.4205° W: Placed by OpenAirDocs at OAKLAND COUNTY INTL (PTK), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=42.6656&lon=-83.4205&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report July 9, 1990
- Report: Approved by Office Director
- NTSB case key (mKey): 13845
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI88DEC02
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/13845/pdf
- Page: https://openairdocs.org/ntsb/CHI88DEC02

## Probable cause

DESTRUCTIVE WING/AILERON FLUTTER IS SUSPECTED, BUT NOT SUFFICIENTLY SUBSTANTIATED THROUGH RESEARCH AND CALCULATIONS TO BE CITED AS THE PROBABLE CAUSE OF THIS ACCIDENT.

## Sequence of events

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

- Airframe/component/system failure/malfunction, maneuvering
  - wing,skin - separation (cause)
  - low pass - intentional, pilot in command
  - acft/equip,inadequate airframe, production/design personnel (cause)
  - design stress limits of aircraft - misjudged, pilot in command
  - flight control,aileron - separation (contributing factor)
  - aircraft control - not possible, pilot in command
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE PILOT WAS TESTING THIS EXPERIMENTAL ACROBATIC AIRCRAFT, MAKING A SECOND LOW PASS OVER THE RUNWAY WHEN A PORTION OF THE LEFT WING SEPARATED FROM THE AIRCRAFT, FOLLOWED BY LOSS OF THE LEFT AILERON, 1 1/2 ROLLS TO THE LEFT AND GROUND IMPACT. THE AIRFRAME TOTAL TIME WAS 4 HOURS. ON-SCENE INSPECTION REVEALED NO MASS BALANCE IN THE AILERONS. WITNESSES ESTIMATE SPEEDS AT OR ABOVE 150 MPH. A DESIGNATED ENGINEERING REPRESENTATIVE IN THE AREA OF FLUTTER AND VIBRATION STATED HE HAD RECOMMENDED THAT THE AIRSPEED BE LIMITED TO A MAXIMUM SPEED OF APPROXIMATELY 135 MPH UNTIL GROUND VIBRATION TESTS WERE CONDUCTED.

## Aircraft

- Registration: [N889HC](https://openairdocs.org/deregistered/N889HC-1992-04-24), registration cancelled 1992-04-24, S/N 2 (OpenAirDocs)
- Reported make and model: CHAPPEL RATSREPUS 300 (RATSREPUS)
- Registry model: [Chappell Harold R JR RATSREPUS](https://openairdocs.org/model/chappell-harold-r-jr-ratsrepus) (registry code 05612WV) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 2
- Airframe hours: 4
- Engines: LYCOMING IO-540-K1A5 300 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Operator: Harold R. Chappel II
- Registered owner: Harold Raymond Chappell II
- Airworthiness certificate: Special, Experimental (Special)
- Departed: PTK, PONTIAC, MI
- Airport: PTK, Oakland/Pontiac, runway 9L, 3,251 × 75 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 48; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: center; toxicology performed; flight hours: 2,810 total, 4 in this make and model, 2,810 as pilot in command

## Weather

- Conditions: Visual (VMC), Day
- Wind: 360° at 15 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F
- Altimeter: 29.00 inHg
- Observed at: PTK

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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