# NTSB CHI71DDJ11: Bell 47D1, N4252A, Manitowish, WI, August 21, 1970

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Closed
- Date: August 21, 1970
- Place: Manitowish, WI · MANITOWISH, WI
- Location: 46.1330° N, 90.0135° W: Placed by OpenAirDocs: center of Manitowish, WI, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=46.1330&lon=-90.0135&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report October 5, 1971
- Report: Brief approved by the director
- NTSB case key (mKey): 107802
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI71DDJ11
- Page: https://openairdocs.org/ntsb/CHI71DDJ11

## NTSB brief

```
----------------------------------------------------------------------------------------------------------------------------
 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA
                                                               F  S M/N     PURPOSE
----------------------------------------------------------------------------------------------------------------------------
3-4481  70/8/21    MANITOWISH,WIS      BELL 47D1           CR-  0  0  1  COMMERCIAL                COMMERCIAL, FL.INSTR.,
        TIME - 0700                    N4252A              PX-  0  0  0  ASSOC CROP CTL ACTIVITY   AGE 36, 6044 TOTAL HOURS,
                                       DAMAGE-SUBSTANTIAL  OT-  0  0  0                            25 IN TYPE, NOT
                                                                                                   INSTRUMENT RATED.
        DEPARTURE POINT             INTENDED DESTINATION
          MANITOWISH WATERS           LOCAL
        TYPE OF ACCIDENT                                         PHASE OF OPERATION
           COLLIDED WITH: TREES                                     IN FLIGHT: OTHER
        PROBABLE CAUSE(S)
           PILOT IN COMMAND - INADEQUATE PREFLIGHT PREPARATION AND/OR PLANNING
           PILOT IN COMMAND - SELECTED UNSUITABLE TERRAIN
           PILOT IN COMMAND - FAILED TO MAINTAIN ADEQUATE ROTOR R.P.M.
           TERRAIN - HIGH OBSTRUCTIONS
         SPECIAL DATA
          TOTAL HOURS IN CROP CONTROL -  900                       KIND OF OPERATION - DEFOLIATION (LIQUID)
          KIND OF CROP - FOREST-TREES                              TYPE OF CHEMICAL USED - LIQUID CHEMICAL-NONTOXIC
          PILOT' S SEAT BELT -UNKNOWN/NOT REPORTED                 GLOVES - NOT USED
          GOGGLES - NOT USED                                       CRASH HELMET - AVAILABLE USED
          COCKPIT CRASHPAD - NOT INSTALLED                         CRASH BAR - NOT INSTALLED
          TANK/HOPPER-LOCATION - SIDES                             TERRAIN-TYPE -LEVEL,FLAT
          ELEVATION-AREA BEING TREATED-FEET -  900                 SWATH RUN-HOW FLOWN - UPWIND
        REMARKS- MADE VER LFT OFF TO TREE TOP LVL LOST ROTOR RPM DURG ATMT ATTAIN TRANSLATIONAL LFT.SETTLD IN TREES
```

## Aircraft

- Registration: [N4252A](https://openairdocs.org/deregistered/N4252A-2017-03-15), registration cancelled 2017-03-15, S/N 117, built 1948 (OpenAirDocs)
- Reported make and model: BELL 47D1
- Registry model: [Bell 47D1](https://openairdocs.org/model/bell-47d1) (registry code 1180802) (OpenAirDocs)
- Registry engine: [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series) (registry code 41525, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Engines: reciprocating
- Damage: Substantial damage

## Other investigations on N4252A (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 MKC66A0065](https://openairdocs.org/ntsb/MKC66A0065), Jun 15, 1966: Bell 47D1 (N4252A), Maple Plain, MN, destroyed

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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