# NTSB MIA90LA182: Hiller OH-23C, N96168, Fort Pierce, FL, September 11, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: September 11, 1990, 10:39 local (14:39 UTC)
- Place: Fort Pierce, FL
- Coordinates: 26.84992, -82.279479 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=26.8499&lon=-82.2795&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report October 2, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 32700
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA90LA182
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/32700/pdf
- Page: https://openairdocs.org/ntsb/MIA90LA182

## Probable cause

LOSS OF ENGINE POWER DUE TO SEPARATION OF THE PACKING SEAL WHICH SEALS THE DISTRIBUTION ZONE PIPE TO THE INLET MANIFOLD, FOR UNDETERMINED REASONS RESULTING IN A HARD LANDING.

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, takeoff - initial climb
  - induction air control,intake manifold - separation (cause)
- Forced landing, descent - emergency
- Hard landing, landing - flare/touchdown
  - proper descent rate - not possible, pilot in command(cfi)

## Analysis

THE CFI STATED THAT HE WAS TEACHING LOW ROTOR RPM RECOVERY TECHNIQUES DURING CLIMB OUT AFTER TAKEOFF. THE STUDENT WAS TO TAKE THE CONTROLS & RECOVER THE HELICOPTER TO A 4 FT HOVER. AT 30 FT, WITH THE ROTOR RPM AT 2,900, THE STUDENT TOOK CONTROL & OPENED THE THROTTLE BUT PULLED COLLECTIVE. THE ENG RPM DROPPED BELOW 2,500. THE CFI TOOK THE CONTROLS, VERIFIED THAT THE THROTTLE WAS OPENED & LOWERED COLLECTIVE. DURING THE RUN-ON LANDING AFTER TOUCHDOWN, THE MAIN ROTOR BLADES CONTACTED THE TAIL BOOM. EXAM OF THE ENG BY A MECHANIC WITH INSPECTION AUTHORIZATION REVEALED THAT ONE OF THE PACKING SEALS WHICH SEAL THE DISTRIBUTION ZONE PIPE TO THE INLET MANIFOLD, SEPARATED FOR UNDETERMINED REASONS RESULTING IN THE PARTIAL LOSS OF ENG POWER.

## Aircraft

- Registration: [N96168](https://openairdocs.org/deregistered/N96168-1998-07-29), registration cancelled 1998-07-29, S/N 554129 (OpenAirDocs)
- Reported make and model: HILLER OH-23C
- Registry model: [Hiller OH-23C](https://openairdocs.org/model/hiller-oh-23c) (registry code 4360119) (OpenAirDocs)
- Category: Helicopter
- Serial number: 55-4129
- Airframe hours: 3742
- Engines: FRANKLIN 6V4-335-13 200 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Coastal Aviation
- Registered owner: Jim Bortnem Ent. Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, May 1, 1990, 88 hours before
- Airport: FPR, St. Lucie County Int'L

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 50; flight instructor, commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 10,000 total, 1,000 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 50° at 12 knots
- Visibility: 5 statute miles
- Lowest ceiling: 3,000 ft broken
- Temperature: 84 °F
- Altimeter: 30.00 inHg
- Observed at: FPR

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19900911038949A](https://openairdocs.org/incident/19900911038949A), Sep 11, 1990: Hiller OH23G, Fort Pierce, FL, Substantial damage. Lost partial power on low level,low RPM power recovery. Chopped tailboom landing. Inlet manifold packing separated.

## Other investigations on N96168 (1)

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.

- [NTSB DEN84LA262](https://openairdocs.org/ntsb/DEN84LA262), Aug 22, 1984: Hiller UH-12C (N96168), Kindred, ND, substantial damage

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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