# NTSB CHI75AC009: Bell 47J-2A, N8525F, Detroit, MI, July 18, 1974

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Closed
- Date: July 18, 1974
- Place: Detroit, MI · DETROIT, MI
- Location: 42.3314° N, 83.0458° W: Placed by OpenAirDocs: center of Detroit, MI, within about 7 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=42.3314&lon=-83.0458&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report July 30, 1974
- Report: Brief approved by the director
- NTSB case key (mKey): 128120
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI75AC009
- Page: https://openairdocs.org/ntsb/CHI75AC009

## NTSB brief

```
----------------------------------------------------------------------------------------------------------------------------
 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA
                                                               F  S M/N     PURPOSE
----------------------------------------------------------------------------------------------------------------------------
3-1927  74/7/18    DETROIT,MICH        BELL 47J-2A         CR-  0  0  1  COMMERCIAL                COMMERCIAL, AGE 47, 8305
        TIME - 2300                    N8525F              PX-  0  0  0  AIR TAXI-CARGO            TOTAL HOURS, 50 IN TYPE,
                                       DAMAGE-DESTROYED    OT-  0  0  0                            NOT INSTRUMENT RATED.
        NAME OF AIRPORT - DETROIT CITY
        DEPARTURE POINT             INTENDED DESTINATION
          PERRYSBURG,OHIO             DETROIT,MICH
        TYPE OF ACCIDENT                                         PHASE OF OPERATION
           PROPELLER/ROTOR FAILURE: TAIL ROTOR                      IN FLIGHT: NORMAL CRUISE
           COLLISION WITH GROUND/WATER: UNCONTROLLED                LANDING: POWER-OFF AUTOROTATIVE LANDING
        PROBABLE CAUSE(S)
           ROTORCRAFT - TRANSMISSION ROTOR DRIVE SYSTEM: TAIL ROTOR DRIVE SHAFT ASSEMBLY
           MISCELLANEOUS ACTS,CONDITIONS - LACK OF LUBRICATION-SPECIFIC PART,NOT SYSTEM
           PILOT IN COMMAND - FAILED TO MAINTAIN DIRECTIONAL CONTROL
           PILOT IN COMMAND - IMPROPER OPERATION OF FLIGHT CONTROLS
        EMERGENCY CIRCUMSTANCES - FORCED LANDING OFF AIRPORT ON LAND
        REMARKS- TAIL ROTOR DRIVE SHORT SHAFT FAILED DUE TO SLIP JOINT COUPLING RUNNING DRY OF GREASE.
```

## Aircraft

- Registration: [N8525F](https://openairdocs.org/deregistered/N8525F-1989-03-14), registration cancelled 1989-03-14, S/N 3319 (OpenAirDocs)
- Reported make and model: BELL 47J-2A
- Registry model: [Bell 47J-2A](https://openairdocs.org/model/bell-47j-2a) (registry code 1181106) (OpenAirDocs)
- Category: Helicopter
- Engines: reciprocating
- Damage: Destroyed
- Airport: Detroit City

## 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 19740718021559A](https://openairdocs.org/incident/19740718021559A), Jul 18, 1974: Bell 47J2A, Detroit, MI, Destroyed. Tail rotor drive short shaft failed due to slip joint coupling running dry of grease.

## Other investigations on N8525F (2)

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 CHI73AC053](https://openairdocs.org/ntsb/CHI73AC053), Dec 5, 1972: Bell 47J-2A (N8525F), Richmond, MI, substantial damage
- [NTSB UNK67X0138](https://openairdocs.org/ntsb/UNK67X0138), Jul 13, 1967: Bell 47J-2 (N8525F), Yukon, Canada, 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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