# NTSB NYC91LA200: Piper PA-12, N4436M, Alton, NH, August 1, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 1, 1991, 14:30 local (18:30 UTC)
- Place: Alton, NH
- Location: 43.4564° N, 71.2223° W: Placed by OpenAirDocs: center of Alton, NH, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=43.4564&lon=-71.2223&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed, report May 27, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 36980
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC91LA200
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/36980/pdf
- Page: https://openairdocs.org/ntsb/NYC91LA200

## Probable cause

THE PILOT'S IMPROPER USE OF CARBURETOR HEAT, WHICH RESULTED IN A LOSS OF ENGINE POWER.

## Sequence of events

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

- Loss of engine power(partial) - nonmechanical, descent - normal
  - powerplant controls - improper use of, pilot in command (cause)
  - fuel system,carburetor - ice (cause)
- Forced landing, descent - emergency
- In flight collision with object, descent - emergency
  - object - tree(s)

## Analysis

THE PILOT REDUCED POWER AND DESCENDED TO 2000 FEET.  WHEN HE APPLIED POWER, THE ENGINE RPM BEGAN TO DROP.  HE USED CARB HEAT, BUT THE RPM DROP CONTINUED.  HE LANDED THE AIRPLANE IN TREES.  THE PILOT SAID, 'I BELIEVE IT WAS CARB ICE. AFTER LIVING IN THE...DESERT FOR 5 YEARS, I'D FORGOTTEN HOW EASY IT WAS TO FORM BACK HERE.'  THE FAA CHART, 'CONDITIONS FAVORING CARB ICE FORMATION,' SHOWS THE EXISTING TEMPERATURE/DEW POINT COULD PRODUCE 'SERIOUS ICING AT CRUISE POWER.' THE PILOT HAD A TOTAL OF 1.5 HOURS FLIGHT TIME IN THE PA-12.

## Aircraft

- Registration: [N4436M](https://openairdocs.org/aircraft/N4436M), registered now, S/N 12-3389, built 1947 (OpenAirDocs)
- Reported make and model: PIPER PA-12
- Registry model: [Piper PA-12](https://openairdocs.org/model/piper-pa-12) (registry code 7101202) (OpenAirDocs)
- Registry engine: [Lycoming 0-235 series](https://openairdocs.org/engine/lycoming-0-235-series) (registry code 41505, 4 cycle) (OpenAirDocs)
- Category: Airplane
- Engines: LYCOMING O-320C 108 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: William Grahn
- Registered owner: William Grahn
- Last inspection: Unknown, January 2, 2000
- Departed: LCI, LACONIA, NH

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; flight hours: 356 total, 2 in this make and model, 316 as pilot in command, 15 in the last 90 days, 9 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 6 knots
- Visibility: 35 statute miles
- Lowest ceiling: none
- Temperature: 84 °F, dew point 52 °F

## 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 19910801036869A](https://openairdocs.org/incident/19910801036869A), Aug 1, 1991: Piper PA12, Alton, NH, Substantial damage. Lost power. Stalled into trees on forced landing. Pilot blamed his failure to timely used carburetor heat.

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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