# NTSB investigations: Franklin 6V4 series

A list on [Franklin 6V4 series](https://openairdocs.org/engine/franklin-6v4-series.md).

Matched to the registry by N-number and event date, newest first.

Page 1 of 6 · 285 investigations

- [NTSB WPR26LA247](https://openairdocs.org/ntsb/WPR26LA247.md): Bell 47G · Springtown, TX · Accident · Serious injuries · Class 4 · Limited · Final report · Jul 3, 2026 · N7985A · Substantial damage
  > The pilot’s failure to maintain clearance from trees while in a low hover.
- [NTSB WPR21LA077](https://openairdocs.org/ntsb/WPR21LA077.md): Bell 47D · Marana, AZ · Accident · Minor injuries · Class 4 · Limited · Final report · Jan 1, 2021 · N74823 · Substantial damage
  > The pilot's failure to maintain helicopter control, which resulted in a hard landing.
- [NTSB CEN17LA264](https://openairdocs.org/ntsb/CEN17LA264.md): Bell 47D1 · Big Lake, MN · Accident · No injuries · Limited investigation · Final report · Jul 6, 2017 · N153B · Substantial damage
  > The failure of the metal core assembly within a wooden main rotor blade due to undetected corrosion and fatigue, which caused the wooden blade to separate from the rotor mast.
- [NTSB CEN17LA113](https://openairdocs.org/ntsb/CEN17LA113.md): Bell-Transworld Helicopters 47D1 · Archer City, TX · Accident · Serious injuries · Limited investigation · Final report · Feb 9, 2017 · N2875F · Substantial damage
  > The total loss of engine power due to fuel starvation, which resulted from the pilot’s inadvertent positioning of the mixture control to the “fuel cutoff” position.
- [NTSB GAA15CA221](https://openairdocs.org/ntsb/GAA15CA221.md): Bell 47D1 · Clanton, AL · Accident · No injuries · Data collection · Final report · Aug 11, 2015 · N74823 · Substantial damage
  > The student pilot's abrupt cyclic and collective inputs during the approach to land which resulted in abnormal runway contact and a subsequent tail boom strike by the main rotor blades.
- [NTSB WPR14LA180](https://openairdocs.org/ntsb/WPR14LA180.md): Bell 47G · El Monte, CA · Accident · Minor injuries · Limited investigation · Final report · May 3, 2014 · N7895B · Substantial damage
  > A partial loss of engine power during climbout due to a malfunctioning magneto and spark plugs.
- [NTSB ERA14LA099](https://openairdocs.org/ntsb/ERA14LA099.md): Bell 47D1 · Pell City, AL · Accident · Minor injuries · Limited investigation · Final report · Jan 21, 2014 · N93067 · Substantial damage
  > The pilot’s use of an improper clutch engagement procedure, which resulted in clutch glazing, slippage, and, ultimately, the in-flight disengagement of the clutch and a loss of rotor rpm. Contributing to the accident were the installation of a light-weight…
- [NTSB ERA13LA390](https://openairdocs.org/ntsb/ERA13LA390.md): Continental Copters 47G · Sandy Hook, KY · Accident · No injuries · Limited investigation · Final report · Aug 31, 2013 · N6356X · Substantial damage
  > The in-flight disengagement of the tail rotor extension shaft from the tail rotor gearbox, resulting in a loss of tail rotor control.
- [NTSB ERA13LA308](https://openairdocs.org/ntsb/ERA13LA308.md): Hiller UH-12A · Florence, AL · Accident · Serious injuries · Limited investigation · Final report · Jun 29, 2013 · N6331D · Substantial damage
  > The student pilot’s failure to maintain control of the helicopter while landing, which resulted in a tail rotor ground strike and collision with terrain.
- [NTSB CEN13LA396](https://openairdocs.org/ntsb/CEN13LA396.md): Bell 47D1 · Lake Ozark, MO · Accident · No injuries · Limited investigation · Final report · Jun 28, 2013 · N78900 · Substantial damage
  > The improper rebuild and maintenance of the helicopter and inadequate subsequent inspections, which resulted in undetected fuel contamination and a subsequent total loss of engine power during cruise flight.
- [NTSB WPR12LA244](https://openairdocs.org/ntsb/WPR12LA244.md): Hiller UH-12B · Pasco, WA · Accident · No injuries · Limited investigation · Final report · Jun 4, 2012 · N93467 · Substantial damage
  > The pilot's failure to maintain the helicopter's rotor rpm while maneuvering at a low altitude over a fruit orchard.
- [NTSB WPR12LA029](https://openairdocs.org/ntsb/WPR12LA029.md): Bell 47D1 · San Diego, CA · Accident · No injuries · Limited investigation · Final report · Nov 8, 2011 · N4251A · Substantial damage
  > The flight instructor's inadequate supervision of the student pilot during a simulated autorotation and the pilots’ failure to use carburetor heat while operating at reduced engine power while in carburetor icing conditions, which resulted in a loss of engine…
- [NTSB WPR11LA469](https://openairdocs.org/ntsb/WPR11LA469.md): Bell 47D1 · Ahwahnee, CA · Accident · Serious injuries · Limited investigation · Final report · Sep 27, 2011 · N9158R · Substantial damage
  > The pilot’s failure to maintain adequate main rotor rpm during the landing approach, which resulted in a loss of control.
- [NTSB ERA10CA262](https://openairdocs.org/ntsb/ERA10CA262.md): Hiller UH12 · Sarasota, FL · Accident · Minor injuries · Data collection · Final report · May 9, 2010 · N116S · Substantial damage
  > The pilot's delayed remedial action to maintain main rotor rpm, which resulted in a loss of lift and hard landing.
- [NTSB ERA10CA001](https://openairdocs.org/ntsb/ERA10CA001.md): Bell 47D1 · Dorrance, PA · Accident · No injuries · Data collection · Final report · Oct 2, 2009 · N74004 · Substantial damage
  > A total loss of engine power due to fuel exhaustion for undetermined reasons.
- [NTSB DFW07WA062](https://openairdocs.org/ntsb/DFW07WA062.md): Hiller UH-12B · Panama City, Panama · Accident · Serious injuries · Foreign investigation · Jan 25, 2007 · N727JR · Substantial damage
- [NTSB LAX06LA030](https://openairdocs.org/ntsb/LAX06LA030.md): Bell 47D1 · Rancho Murieta, CA · Accident · Serious injuries · Limited investigation · Final report · Nov 10, 2005 · N16356 · Substantial damage
  > a separation of the tail rotor assembly due to the reverse bending fatigue fracture of a tail rotor pitch change link bolt, resulting in a loss of control of the helicopter, and a hard landing during the uncontrolled descent.
- [NTSB LAX05LA112](https://openairdocs.org/ntsb/LAX05LA112.md): Hiller UH-12B · Thermal, CA · Accident · No injuries · Limited investigation · Final report · Mar 12, 2005 · N5311V · Substantial damage
  > the pilot's inadequate in-flight planning and failure to refuel the helicopter, which resulted in fuel exhaustion.
- [NTSB LAX05LA022](https://openairdocs.org/ntsb/LAX05LA022.md): Bell 47D1 · San Martin, CA · Accident · No injuries · Limited investigation · Final report · Oct 31, 2004 · N903B · Substantial damage
  > A loss of power for undetermined reasons.
- [NTSB ANC04LA027](https://openairdocs.org/ntsb/ANC04LA027.md): Hiller UH-12B · Bradenton, FL · Accident · No injuries · Limited investigation · Final report · Feb 22, 2004 · N5304V · Substantial damage
  > The pilot's inadequate in-flight planning/decision which resulted in fuel exhaustion. Also causal was the pilot's failure to maintain adequate rotor speed, resulting in a hard landing.
- [NTSB NYC03LA069](https://openairdocs.org/ntsb/NYC03LA069.md): Bell 47D · Princetown, NY · Accident · Minor injuries · Limited investigation · Final report · Mar 23, 2003 · N74120 · Substantial damage
  > The student's failure to maintain control while executing a takeoff to a hover, and the flight instructor's delayed remedial action. A factor in the accident was the muddy ground.
- [NTSB FTW02LA044](https://openairdocs.org/ntsb/FTW02LA044.md): Bell 47G · Ardmore, OK · Accident · No injuries · Limited investigation · Final report · Dec 1, 2001 · N5226 · Substantial damage
  > the flight instructor's selection of an unsuitable area for practicing a full touchdown autorotation, which resulted in a nose over. A contributing factor was the soft ground.
- [NTSB ATL01LA108](https://openairdocs.org/ntsb/ATL01LA108.md): Bell 47G · Berry, AL · Accident · No injuries · Limited investigation · Final report · Sep 7, 2001 · N6327D · Substantial damage
  > The failure of the main rotor system stabilizer damper control horn assembly, resulting in an uncontrolled descent and subsequent collision with a tree and terrain.
- [NTSB CHI01FA231](https://openairdocs.org/ntsb/CHI01FA231.md): World Helicopters 47D1 · Ballard, MO · Accident · 2 fatal · Field investigation · Final report · Jul 22, 2001 · N17301 · Destroyed
  > The pilot's improper preflight planning which resulted in fuel exhaustion, and the pilot's subsequent improper autorotation.
- [NTSB LAX00LA288](https://openairdocs.org/ntsb/LAX00LA288.md): Bell 47D · Stockton, CA · Accident · No injuries · Limited investigation · Final report · Aug 5, 2000 · N39KH · Substantial damage
  > The pilot's inadequate planning by which he miscalculated fuel consumption which resulted in fuel exhaustion.
- [NTSB MIA00LA111](https://openairdocs.org/ntsb/MIA00LA111.md): Hiller UH-12B · Sanford, FL · Accident · Minor injuries · Limited investigation · Final report · Mar 17, 2000 · N5304V · Substantial damage
  > The pilot's improper collective and cyclic control usage during an emergency descent, following the onset of a 1 to 1 vibration for undetermined reasons, resulting in the helicopter landing hard and rolling over.
- [NTSB NYC00LA044](https://openairdocs.org/ntsb/NYC00LA044.md): Bell 47G · Coudersport, PA · Accident · No injuries · Limited investigation · Final report · Nov 27, 1999 · N940B · Substantial damage
  > The pilot's improper preflight planning and decision to attempt a takeoff with the passenger from the confined area.
- [NTSB ATL99LA108](https://openairdocs.org/ntsb/ATL99LA108.md): Hiller UH12-C · Venice, FL · Accident · No injuries · Limited investigation · Final report · Jul 16, 1999 · N5317V · Substantial damage
  > Loss of engine power due to fuel starvation as a result of the passenger inadvertently shutting off the fuel supply.
- [NTSB CHI99LA012](https://openairdocs.org/ntsb/CHI99LA012.md): Hiller UH-12C · Clinton, IA · Accident · No injuries · Limited investigation · Final report · Oct 24, 1998 · N9739C · Substantial damage
  > the failure of the 90 degree gearbox for reasons undetermined. Factors were the failure of the gearbox, and it not being possible for the pilot to maintain control of the aircraft.
- [NTSB MIA98LA254](https://openairdocs.org/ntsb/MIA98LA254.md): Bell 47-D1 · Oxford, MS · Accident · Minor injuries · Limited investigation · Final report · Sep 29, 1998 · N755E · Substantial damage
  > The pilot's failure to maintain directional control due to vibration from the main rotor blade for undetermined reasons. A related finding was the improper repair of a crack in the laminant of the blue main rotor blade by other maintenance personnel.
- [NTSB MIA98LA170](https://openairdocs.org/ntsb/MIA98LA170.md): Bell 47G · Bunnell, FL · Accident · No injuries · Limited investigation · Final report · May 28, 1998 · N182JR · Substantial damage
  > The pilot-in-command(CFI) failure to maintain control of the aircraft.
- [NTSB FTW98LA144](https://openairdocs.org/ntsb/FTW98LA144.md): Bell 47D1 · Jeanerette, LA · Accident · Minor injuries · Limited investigation · Final report · Mar 11, 1998 · N13012 · Substantial damage
  > The in-flight disconnect of the rotating scissors due to the separation of its hinge bolt.
- [NTSB MIA98LA051](https://openairdocs.org/ntsb/MIA98LA051.md): Bell 47D1 · Bunnell, FL · Accident · No injuries · Limited investigation · Final report · Jan 3, 1998 · N59326 · Substantial damage
  > the student pilot's improper planning/decision, which resulted in fuel exhaustion, loss of engine power, and a forced landing.
- [NTSB MIA97FA248](https://openairdocs.org/ntsb/MIA97FA248.md): Bell 47G · Saluda, SC · Accident · 2 fatal · Field investigation · Final report · Sep 19, 1997 · N70747 · Destroyed
  > in-flight collision with a tree, for undetermined reason(s).
- [NTSB ATL97LA121](https://openairdocs.org/ntsb/ATL97LA121.md): Bell 47-D1 · Holcomb, MS · Accident · No injuries · Limited investigation · Final report · Aug 11, 1997 · N908B · Substantial damage
  > The failure of the pilot to adequately see and avoid all obstructions while doing aerial application work.
- [NTSB FTW96LA192](https://openairdocs.org/ntsb/FTW96LA192.md): Bell 47D1 · Ardmore, OK · Accident · No injuries · Limited investigation · Final report · Apr 26, 1996 · N5226 · Substantial damage
  > the student's inadvertent dynamic rollover, and inadequate supervision by the flight instructor.
- [NTSB ATL96LA023](https://openairdocs.org/ntsb/ATL96LA023.md): Hiller 12C · N. Myrtle Beach, SC · Accident · No injuries · Limited investigation · Final report · Dec 18, 1995 · N234SM · Substantial damage
  > The pilot's improper operation of the flight controls during a practice autorotation, and the certified flight instructor's inadequate supervision of the operation
- [NTSB LAX96FA045](https://openairdocs.org/ntsb/LAX96FA045.md): Bell 47D1 · Shafter, CA · Accident · 2 fatal · Field investigation · Final report · Nov 12, 1995 · N78900 · Destroyed
  > the pilot misjudged the altitude and ground clearance while performing an unwarranted low altitude flight maneuver.
- [NTSB LAX95LA326](https://openairdocs.org/ntsb/LAX95LA326.md): Hiller UH-12C · Porterville, CA · Accident · Minor injuries · Limited investigation · Final report · Sep 6, 1995 · N1348Z · Substantial damage
  > the flight instructor's inadequate supervision of the flight; the dual student's improper use of the flight controls; and improper remedial action.
- [NTSB LAX95LA238](https://openairdocs.org/ntsb/LAX95LA238.md): Hiller UH-12C · Rio Vista, CA · Accident · No injuries · Limited investigation · Final report · Jul 3, 1995 · N1348Z · Substantial damage
  > The result of a chafing failure of the left anti-torque control cable while the aircraft was in flight. An inadequate preflight inspection by the pilot-in-command, and an inadequate 100-hour inspection by company maintenance personnel were factors in this…
- [NTSB ATL94LA172](https://openairdocs.org/ntsb/ATL94LA172.md): Bell 47D1 Wasp · Hazel Green, AL · Accident · No injuries · Limited investigation · Final report · Sep 13, 1994 · N908B · Substantial damage
  > Undetermined.
- [NTSB FTW94LA221](https://openairdocs.org/ntsb/FTW94LA221.md): Bell OH-13E · Mountain View, AR · Accident · No injuries · Limited investigation · Final report · Jul 3, 1994 · N39WL · Substantial damage
  > The fuel exhaustion as result of a struck fuel drain valve. Factors were the high density altitude, and the unsuitable terrain at the pilot's disposal for the forced landing.
- [NTSB FTW94LA193](https://openairdocs.org/ntsb/FTW94LA193.md): Bell 47H-1 · Tulsa, OK · Accident · No injuries · Limited investigation · Final report · Jun 4, 1994 · N2831B · Substantial damage
  > The pilot's failure to maintain rotor RPM, his delayed landing flare, and the improper touchdown.
- [NTSB FTW94LA166](https://openairdocs.org/ntsb/FTW94LA166.md): Bell 47G · Sulphur, OK · Accident · No injuries · Limited investigation · Final report · May 18, 1994 · N933B · Substantial damage
  > The loss of engine power due to the failure of an engine accessory oil pump gear. A factor was the lack of suitable terrain for the autorotation.
- [NTSB MIA94FA125](https://openairdocs.org/ntsb/MIA94FA125.md): Bell 47D1 · Marathon, FL · Accident · 2 fatal · Field investigation · Final report · Apr 22, 1994 · N9660 · Destroyed
  > Separation of the tail rotor gearbox and tail rotor blades for an undetermined reason. Factors related to the accident were: failure of maintenance personnel to follow the proper maintenance procedure after a previous tail rotor strike, and failure to conduct…
- [NTSB MIA93LA144](https://openairdocs.org/ntsb/MIA93LA144.md): Bell 47G · Panama City, FL · Accident · Minor injuries · Limited investigation · Final report · Jun 19, 1993 · N3628G · Substantial damage
  > Improper planning/decision by the pilot-in-command and his failure to maintain rotor RPM, which resulted in failure of the helicopter to attain effective translational lift. Factors related to the accident were: the fence & terrain conditions.
- [NTSB MIA93LA032](https://openairdocs.org/ntsb/MIA93LA032.md): Hiller UH-12C · New Smyrna Bch, FL · Accident · No injuries · Limited investigation · Final report · Dec 21, 1992 · N38767 · Substantial damage
  > The pilot-in-command's improper application of cyclic and collective pitch control during an autorotative landing.
- [NTSB SEA92LA141](https://openairdocs.org/ntsb/SEA92LA141.md): Bell-World 47D1 · Wenatchee, WA · Accident · No injuries · Limited investigation · Final report · Jun 29, 1992 · N17301 · Destroyed
  > Carburetor ice and the pilot in command's not being able to maintain clearance. Factors contributing to the accident were: carburetor icing conditions and tree(s).
- [NTSB MIA92LA102](https://openairdocs.org/ntsb/MIA92LA102.md): Bell 47-D-1 · Fayette, MS · Accident · Minor injuries · Limited investigation · Final report · Apr 2, 1992 · N322A · Substantial damage
  > The pilot in commands failure to insure the proper fuel quantity for the flight was placed on the aircraft and his failure to monitor fuel quantity during flight resulting in fuel exhaustion.
- [NTSB MIA92LA069](https://openairdocs.org/ntsb/MIA92LA069.md): Bell 47D1 · Cross City, FL · Accident · No injuries · Limited investigation · Final report · Jan 27, 1992 · N93067 · Substantial damage
  > Partial loss of engine power due to undetermined reasons and unsuitable terrain encountered during the autorotative landing.

Next page: https://openairdocs.org/engine/franklin-6v4-series/ntsb.md?page=2

## The whole list in SQL

Runs in DuckDB 1.2 or later on the release's Parquet files over HTTPS:

```sql
SELECT c."ntsbNumber", c."eventDate", c."eventType", c."eventCity", c."eventStateOrRegion", a.n_number, a."aircraftMake", a."aircraftModel", c."highestInjuryLevel", c."totalFatal", c."completionStatus", c.report_url
FROM 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a JOIN 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c ON c."mKey" = a.case_mkey
WHERE a.engine_model_code IN ('27033')
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/engine/franklin-6v4-series/ntsb

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