# Sikorsky S-61N

- Type: Aircraft model (FAA registry)
- Registry code: 8142104
- Manufacturer (registry): SIKORSKY
- Model: S-61N
- Aircraft type: Rotorcraft
- Category: Rotorcraft
- Engines: 2 · Turbo-shaft
- Seats: 28
- Weight class: 12,500 to 19,999 lb
- Cruise speed: 112 mph
- Certification: Type certificated
- Data sheet: [TCDS 1H15](https://openairdocs.org/tcds/1H15) (OpenAirDocs)
- Holder: Sikorsky Aircraft
- Registered aircraft: 45
- Page: https://openairdocs.org/model/sikorsky-s-61n

Model codes come from the FAA registry's reference file. ADs are matched to them by model name and maker.

## ADs that may apply (OpenAirDocs)

Matched to this model by model name and maker. Each AD's applicability may narrow it by serial number, part number or equipment.

- [AD 2026-15-17](https://openairdocs.org/ad/2026-15-17): Main Rotor Gearbox · Glacier Helicopter CH-3E, S-61A, S-61D and 12 more. Effective Sep 10, 2026
- [AD 2026-11-05](https://openairdocs.org/ad/2026-11-05): Rotorcraft flight control; Rotorcraft servo system · Carson Helicopters S-61L, SH-3H, CH-3E and 11 more. Effective Jul 9, 2026
- [AD 2023-11-07](https://openairdocs.org/ad/2023-11-07): Ground Proximity System · Airbus Helicopters 47, 206, 210 and 237 more. Effective Jun 22, 2023
- [AD 2022-05-10](https://openairdocs.org/ad/2022-05-10): Cabin Equipment/Furnishings · Airbus Helicopters AS332L, AS332L1, AS332L2 and 57 more. Effective Apr 20, 2022
- [AD 2021-05-19](https://openairdocs.org/ad/2021-05-19): Tail Rotor Control System · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective May 7, 2021
- [AD 2013-06-51](https://openairdocs.org/ad/2013-06-51): Equipment/Furnishings · Agusta A109, A109A, A109A II and 43 more. Effective Jul 15, 2013
- [AD 2013-05-17](https://openairdocs.org/ad/2013-05-17): Aircraft Fuel Filter/Strainer · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Apr 26, 2013
- [AD 2007-01-05](https://openairdocs.org/ad/2007-01-05): Main gearbox input left and right freewheel unit (IFWU) assembly · Sikorsky S-61L, S-61N, S-61NM and 1 more. Effective Feb 14, 2007
- [AD 2004-15-22](https://openairdocs.org/ad/2004-15-22): Bearing chip detector · Sikorsky S-61L, S-61N, S-61NM and 1 more. Effective Sep 7, 2004
- [AD 2002-20-05](https://openairdocs.org/ad/2002-20-05): Rescue hoists · Agusta A109, A109A, A109A II and 31 more. Effective Nov 7, 2002
- [AD 2000-13-06](https://openairdocs.org/ad/2000-13-06): Web Fittings · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Jul 18, 2000
- [AD 98-26-02](https://openairdocs.org/ad/98-26-02): Shaft · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Jan 20, 1999
- [AD 97-19-06](https://openairdocs.org/ad/97-19-06): Blade Trailing Edge Pocket Assemblies · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Oct 6, 1997
- [AD 91-12-01](https://openairdocs.org/ad/91-12-01): Sleeve & Spindle Assemblies · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Jul 8, 1991
- [AD 90-01-04](https://openairdocs.org/ad/90-01-04): Main Rotor Hub Upper Plate · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Feb 5, 1990
- [AD 89-04-01 R3](https://openairdocs.org/ad/89-04-01-R3): Truss Tube Assemblies · Sikorsky S-61N and S-61NM. Effective Feb 5, 1990
- [AD 89-07-09](https://openairdocs.org/ad/89-07-09): Main Rotor Gearbox · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Apr 20, 1989
- [AD 85-18-05 R2](https://openairdocs.org/ad/85-18-05-R2): Main Rotor Blades · Sikorsky S-61A, S-61L, S-61N and 3 more. Effective Feb 8, 1989
- [AD 87-15-11](https://openairdocs.org/ad/87-15-11): Gearbox Brackets · Sikorsky S-61A, S-61L, S-61N and 3 more. Effective Aug 10, 1987
- [AD 86-23-08](https://openairdocs.org/ad/86-23-08): Main Rotor Hub Lower Plate · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Apr 21, 1987
- [AD 84-25-01](https://openairdocs.org/ad/84-25-01): Main Gearbox Inspection · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Jan 19, 1985
- [AD 84-11-03](https://openairdocs.org/ad/84-11-03): Possible Flange Failure · Sikorsky S-61A, S-61L and S-61N. Effective Jun 6, 1984
- [AD 84-01-51](https://openairdocs.org/ad/84-01-51): Rotary Wing Head Shaft Nut · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Mar 27, 1984
- [AD 74-20-07 R5](https://openairdocs.org/ad/74-20-07-R5): Main Rotor Blades · Sikorsky S-61A, S-61L, S-61N and 3 more. Effective Dec 30, 1983
- [AD 78-20-05 R4](https://openairdocs.org/ad/78-20-05-R4): Main Rotor Spindles · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective May 25, 1983
- [AD 80-17-07](https://openairdocs.org/ad/80-17-07): Horizontal Hinge Pins · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Aug 15, 1980
- [AD 78-05-07](https://openairdocs.org/ad/78-05-07): Main Landing Gear · Sikorsky S-61N. Effective Apr 13, 1978
- [AD 74-20-09](https://openairdocs.org/ad/74-20-09): Main Rotor Blades · Sikorsky S-61A, S-61L, S-61N and 2 more. Effective Feb 25, 1977
- [AD 76-06-01](https://openairdocs.org/ad/76-06-01): Hydraulic Pumps · Erickson Air-Crane S-64A, S-64E, S-64F and 12 more. Effective Mar 24, 1976
- [AD 76-03-02](https://openairdocs.org/ad/76-03-02): Fractures in Barrel Nuts · Sikorsky S-61L, S-61N, S-61NM and 1 more. Effective Feb 17, 1976
- [AD 75-26-10](https://openairdocs.org/ad/75-26-10): Component Replacement · Sikorsky S-61L, S-61N and S-61NM. Effective Jan 2, 1976
- [AD 68-19-07](https://openairdocs.org/ad/68-19-07): Rotor Blade Spindles · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Dec 23, 1975
- [AD 75-17-33](https://openairdocs.org/ad/75-17-33): Baggage Doors · Sikorsky S-61L, S-61N and S-61NM. Effective Oct 3, 1975
- [AD 75-12-01](https://openairdocs.org/ad/75-12-01): Main Rotor Blades · Sikorsky S-61L, S-61N, S-61NM and 1 more. Effective Jun 12, 1975
- [AD 74-25-05](https://openairdocs.org/ad/74-25-05): Main Rotor Blades · Sikorsky S-61L, S-61N, S-61NM and 1 more. Effective Nov 6, 1974
- [AD 74-25-06](https://openairdocs.org/ad/74-25-06): Takeoff Gross Weight Limitation · Sikorsky S-61L, S-61N and S-61NM. Effective Oct 16, 1974
- [AD 72-25-04](https://openairdocs.org/ad/72-25-04): Loss of Main Rotor Control · Sikorsky S-61A, S-61D, S-61L and 3 more. Effective Dec 15, 1972
- [AD 72-16-06](https://openairdocs.org/ad/72-16-06): Electrical Feeder Wire Gage · Sikorsky S-61A, S-61L, S-61N and 1 more. Effective Aug 10, 1972
- [AD 72-03-01](https://openairdocs.org/ad/72-03-01): Alum. Forgings Flight Control System · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Feb 1, 1972
- [AD 71-21-03](https://openairdocs.org/ad/71-21-03): Link in Servo Valve Input Linkage · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Oct 7, 1971
- [AD 71-05-01](https://openairdocs.org/ad/71-05-01): Main Landing Gear Axle · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Feb 23, 1971
- [AD 68-20-08](https://openairdocs.org/ad/68-20-08): Functional Test of AFCS · Sikorsky S-61A, S-61L and S-61N. Effective Jan 14, 1971
- [AD 70-15-01](https://openairdocs.org/ad/70-15-01): Cabin Heater Blower · Sikorsky S-61A, S-61L, S-61N and 1 more. Effective Jul 22, 1970
- [AD 70-09-03](https://openairdocs.org/ad/70-09-03): Tail Gear Box Pitch Beams · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective May 8, 1970
- [AD 70-08-03](https://openairdocs.org/ad/70-08-03): Heater Inlet Check Valve · Sikorsky S-61A, S-61L, S-61N and 1 more. Effective Mar 17, 1970
- [AD 68-21-06](https://openairdocs.org/ad/68-21-06): Deactivate AFCS · Sikorsky S-61A, S-61L and S-61N. Effective Oct 24, 1968
- [AD 67-29-05](https://openairdocs.org/ad/67-29-05): Rotary Wing Hub Hinge Pins · Sikorsky S-61A, S-61D, S-61E and 5 more. Effective Oct 30, 1967
- [AD 66-19-04](https://openairdocs.org/ad/66-19-04): Tail Rotor Blades · Sikorsky S-58A, S-58B, S-58BT and 20 more. Effective Aug 14, 1966
- [AD 65-08-02](https://openairdocs.org/ad/65-08-02): Main Rotor Blades · Orlando Helicopter Airways HRS-1/CH-19, HRS-3/H-19B, S-55 and 11 more. Effective Apr 9, 1965
- [AD 85-15-05](https://openairdocs.org/ad/85-15-05): Main Rotor Horn Eyebolt/Eyebolt Assembly · Sikorsky S-61L, S-61N and S-61NM

Historical (superseded or no longer in force):

- [AD 2021-23-13](https://openairdocs.org/ad/2021-23-13) (historical): Ground Proximity System · Airbus Helicopters K-225, K-190A, K-240 and 237 more. Effective Dec 9, 2021
- [AD 2015-20-12](https://openairdocs.org/ad/2015-20-12) (historical): Main Rotor Gearbox · Carson Helicopters SH-3H, SH-3H, CH-3E and 13 more. Effective Nov 24, 2015
- [AD 97-10-04](https://openairdocs.org/ad/97-10-04) (historical): Blade Trailing Edge Pocket Assemblies · Sikorsky S-61A, S-61D, S-61E and 5 more

All 56: https://openairdocs.org/model/sikorsky-s-61n/ads.md

## Registered aircraft (45)

- [N138AR](https://openairdocs.org/aircraft/N138AR): [Amentum Services Inc](https://openairdocs.org/faa-owner/AMENTUM%20SERVICES%20INC), [West Palm Beach, FL](https://openairdocs.org/faa-place/FL/West%20Palm%20Beach), built 1977, S/N 61767
- [N161CG](https://openairdocs.org/aircraft/N161CG): [Csc Delaware Trust Co Trustee](https://openairdocs.org/faa-owner/CSC%20DELAWARE%20TRUST%20CO%20TRUSTEE), [Wilmington, DE](https://openairdocs.org/faa-place/DE/Wilmington), built 1968, S/N 61363
- [N232AC](https://openairdocs.org/aircraft/N232AC): [Amentum Services Inc](https://openairdocs.org/faa-owner/AMENTUM%20SERVICES%20INC), [West Palm Beach, FL](https://openairdocs.org/faa-place/FL/West%20Palm%20Beach), built 1969, S/N 61470
- [N261CG](https://openairdocs.org/aircraft/N261CG): [Csc Delaware Trust Co Trustee](https://openairdocs.org/faa-owner/CSC%20DELAWARE%20TRUST%20CO%20TRUSTEE), [Wilmington, DE](https://openairdocs.org/faa-place/DE/Wilmington), built 1985, S/N 61257
- [N408FS](https://openairdocs.org/aircraft/N408FS): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1966, S/N 61361
- [N408UD](https://openairdocs.org/aircraft/N408UD): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1974, S/N 61772
- [N408WC](https://openairdocs.org/aircraft/N408WC): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1977, S/N 61764
- [N410GH](https://openairdocs.org/aircraft/N410GH): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1975, S/N 61749
- [N448JS](https://openairdocs.org/aircraft/N448JS): [Bank Of Utah Trustee](https://openairdocs.org/faa-owner/BANK%20OF%20UTAH%20TRUSTEE), [Salt Lake City, UT](https://openairdocs.org/faa-place/UT/Salt%20Lake%20City), built 1968, S/N 61428
- [N471WR](https://openairdocs.org/aircraft/N471WR): [Coulson Aviation USA Inc](https://openairdocs.org/faa-owner/COULSON%20AVIATION%20USA%20INC), [Portland, OR](https://openairdocs.org/faa-place/OR/Portland), built 1969, S/N 61471
- [N476AW](https://openairdocs.org/aircraft/N476AW): [Construction Helicopters LLC](https://openairdocs.org/faa-owner/CONSTRUCTION%20HELICOPTERS%20LLC), [Howell, MI](https://openairdocs.org/faa-place/MI/Howell), built 1971, S/N 61476
- [N614CK](https://openairdocs.org/aircraft/N614CK): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1974, S/N 61715
- [N617CK](https://openairdocs.org/aircraft/N617CK): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1962, S/N 61164
- [N619CK](https://openairdocs.org/aircraft/N619CK): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), S/N 61808
- [N61NH](https://openairdocs.org/aircraft/N61NH): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1970, S/N 61474
- [N61NW](https://openairdocs.org/aircraft/N61NW): [US Leaseco Inc](https://openairdocs.org/faa-owner/US%20LEASECO%20INC), [Aurora, OR](https://openairdocs.org/faa-place/OR/Aurora), built 1974, S/N 61719
- [N621CK](https://openairdocs.org/aircraft/N621CK): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), S/N 61364
- [N623CK](https://openairdocs.org/aircraft/N623CK): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1977, S/N 61762
- [N625CK](https://openairdocs.org/aircraft/N625CK): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1963, S/N 61-216
- [N626CK](https://openairdocs.org/aircraft/N626CK): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1963, S/N 61220
- [N627CK](https://openairdocs.org/aircraft/N627CK): [Southern Aircraft Consultancy Inc Trustee](https://openairdocs.org/faa-owner/SOUTHERN%20AIRCRAFT%20CONSULTANCY%20INC%20TRUSTEE), [Casper, WY](https://openairdocs.org/faa-place/WY/Casper), built 1980, S/N 61824
- [N629CK](https://openairdocs.org/aircraft/N629CK): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1975, S/N 61751
- [N631CK](https://openairdocs.org/aircraft/N631CK): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), S/N 61753
- [N703HG](https://openairdocs.org/aircraft/N703HG): [Construction Helicopters LLC](https://openairdocs.org/faa-owner/CONSTRUCTION%20HELICOPTERS%20LLC), [Howell, MI](https://openairdocs.org/faa-place/MI/Howell), built 1972, S/N 61703
- [N712HG](https://openairdocs.org/aircraft/N712HG): [Construction Helicopters LLC](https://openairdocs.org/faa-owner/CONSTRUCTION%20HELICOPTERS%20LLC), [Howell, MI](https://openairdocs.org/faa-place/MI/Howell), built 1973, S/N 61712
- [N718HG](https://openairdocs.org/aircraft/N718HG): [Construction Helicopters LLC](https://openairdocs.org/faa-owner/CONSTRUCTION%20HELICOPTERS%20LLC), [Howell, MI](https://openairdocs.org/faa-place/MI/Howell), S/N 61718
- [N745AW](https://openairdocs.org/aircraft/N745AW): [Coulson Aviation USA Inc](https://openairdocs.org/faa-owner/COULSON%20AVIATION%20USA%20INC), [Portland, OR](https://openairdocs.org/faa-place/OR/Portland), S/N 61745
- [N7563W](https://openairdocs.org/aircraft/N7563W): [Withrotor Aviation Inc](https://openairdocs.org/faa-owner/WITHROTOR%20AVIATION%20INC), [Lakeview, OR](https://openairdocs.org/faa-place/OR/Lakeview), S/N 61752
- [N760HT](https://openairdocs.org/aircraft/N760HT): [U S Leaseco Inc](https://openairdocs.org/faa-owner/U%20S%20LEASECO%20INC), [Aurora, OR](https://openairdocs.org/faa-place/OR/Aurora), built 1978, S/N 61811
- [N761HG](https://openairdocs.org/aircraft/N761HG): [Construction Helicopters LLC](https://openairdocs.org/faa-owner/CONSTRUCTION%20HELICOPTERS%20LLC), [Howell, MI](https://openairdocs.org/faa-place/MI/Howell), built 1977, S/N 61761
- [N762HT](https://openairdocs.org/aircraft/N762HT): [US Leaseco Inc](https://openairdocs.org/faa-owner/US%20LEASECO%20INC), [Aurora, OR](https://openairdocs.org/faa-place/OR/Aurora), built 1976, S/N 61755
- [N765AW](https://openairdocs.org/aircraft/N765AW): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1976, S/N 61765
- [N773WC](https://openairdocs.org/aircraft/N773WC): [Integrity Aircraft Title Holdings LLC](https://openairdocs.org/faa-owner/INTEGRITY%20AIRCRAFT%20TITLE%20HOLDINGS%20LLC), [Portland, OR](https://openairdocs.org/faa-place/OR/Portland), built 1978, S/N 61807
- [N775HG](https://openairdocs.org/aircraft/N775HG): [Construction Helicopters LLC](https://openairdocs.org/faa-owner/CONSTRUCTION%20HELICOPTERS%20LLC), [Howell, MI](https://openairdocs.org/faa-place/MI/Howell), built 1977, S/N 61775
- [N804AR](https://openairdocs.org/aircraft/N804AR): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1964, S/N 61222
- [N825WL](https://openairdocs.org/aircraft/N825WL): [Heligroup Fire LLC](https://openairdocs.org/faa-owner/HELIGROUP%20FIRE%20LLC), [Missoula, MT](https://openairdocs.org/faa-place/MT/Missoula), built 1980, S/N 61825
- [N826WC](https://openairdocs.org/aircraft/N826WC): [Construction Helicopters LLC](https://openairdocs.org/faa-owner/CONSTRUCTION%20HELICOPTERS%20LLC), [Howell, MI](https://openairdocs.org/faa-place/MI/Howell), built 1980, S/N 61826
- [N827HG](https://openairdocs.org/aircraft/N827HG): [Construction Helicopters LLC](https://openairdocs.org/faa-owner/CONSTRUCTION%20HELICOPTERS%20LLC), [Howell, MI](https://openairdocs.org/faa-place/MI/Howell), built 1980, S/N 61827
- [N833AR](https://openairdocs.org/aircraft/N833AR): [Croman Corp](https://openairdocs.org/faa-owner/CROMAN%20CORP), [White City, OR](https://openairdocs.org/faa-place/OR/White%20City), built 1974, S/N 61738
- [N904CH](https://openairdocs.org/aircraft/N904CH): [Construction Helicopters LLC](https://openairdocs.org/faa-owner/CONSTRUCTION%20HELICOPTERS%20LLC), [Howell, MI](https://openairdocs.org/faa-place/MI/Howell), built 1977, S/N 61777
- [N905CH](https://openairdocs.org/aircraft/N905CH): [Construction Helicopters LLC](https://openairdocs.org/faa-owner/CONSTRUCTION%20HELICOPTERS%20LLC), [Howell, MI](https://openairdocs.org/faa-place/MI/Howell), S/N 61711
- [N906CH](https://openairdocs.org/aircraft/N906CH): [Construction Helicopters LLC](https://openairdocs.org/faa-owner/CONSTRUCTION%20HELICOPTERS%20LLC), [Howell, MI](https://openairdocs.org/faa-place/MI/Howell), built 1971, S/N 61490
- [N907CH](https://openairdocs.org/aircraft/N907CH): [Heligroup Fire LLC](https://openairdocs.org/faa-owner/HELIGROUP%20FIRE%20LLC), [Missoula, MT](https://openairdocs.org/faa-place/MT/Missoula), built 1979, S/N 61819
- [N91158](https://openairdocs.org/aircraft/N91158): [US Leaseco Inc](https://openairdocs.org/faa-owner/US%20LEASECO%20INC), [Aurora, OR](https://openairdocs.org/faa-place/OR/Aurora), built 1968, S/N 61424
- [N968CL](https://openairdocs.org/aircraft/N968CL): [Clayton International Inc](https://openairdocs.org/faa-owner/CLAYTON%20INTERNATIONAL%20INC), [Peachtree City, GA](https://openairdocs.org/faa-place/GA/Peachtree%20City), built 1978, S/N 61816

## NTSB investigations (11)

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 GAA25WA145](https://openairdocs.org/ntsb/GAA25WA145), Jan 10, 2025: Sikorsky S-61N (N703HG), Sédjè, Benin, substantial damage
- [NTSB WPR22LA330](https://openairdocs.org/ntsb/WPR22LA330), Sep 1, 2022: Sikorsky S-61N (N617CK), Shady Cove, OR, substantial damage. Probable cause: A total loss of engine power due to the failure of the No. 2 engine’s stage 1 turbine blades as a result of an unreported hot start two days earlier.
- [NTSB ANC22FA018](https://openairdocs.org/ntsb/ANC22FA018), Feb 22, 2022: Sikorsky S-61N (N615CK), Kekaha, HI, destroyed, 4 fatal. Probable cause: The improper installation of the fore/aft primary servo by maintenance personnel, which resulted in the attaching hardware backing out and which subsequently rendered the helicopter uncontrollable.…
- [NTSB DCA20LA100](https://openairdocs.org/ntsb/DCA20LA100), Apr 20, 2020: Sikorsky S61 (N908CH), Camp Dwyer, Afghanistan, substantial damage. Probable cause: Fatigue cracking of the auxiliary servo cylinder’s pedal damper check valve housing and its bolts, which caused the sudden and uncommanded movement of the helicopter’s left pedal and a subsequent…
- [NTSB ERA16FA311](https://openairdocs.org/ntsb/ERA16FA311), Sep 6, 2016: Sikorsky S61 (N805AR), Palm Bay, FL, destroyed, 3 fatal. Probable cause: A dual loss of engine power for undetermined reasons after the pilot's improper decision to attempt another maneuver after recovering from a perceived compressor stall, rather than returning to the…
- [NTSB LAX08PA259](https://openairdocs.org/ntsb/LAX08PA259), Aug 6, 2008: Sikorsky S-61N (N612AZ), Weaverville, CA, destroyed, 9 fatal. Probable cause: The following actions by Carson Helicopters: 1) the intentional understatement of the helicopter's empty weight, 2) the alteration of the power available chart to exaggerate the helicopter's lift…
- [NTSB NYC08WA256](https://openairdocs.org/ntsb/NYC08WA256), Jul 19, 2008: Sikorsky S-61N (N91158), Cusco, Peru, substantial damage
- [NTSB SEA76FYA05](https://openairdocs.org/ntsb/SEA76FYA05), Jul 22, 1975: Sikorsky S-61L (N301Y), Garden Valley, ID, substantial damage
- [NTSB OAK73IP020](https://openairdocs.org/ntsb/OAK73IP020), Nov 17, 1973: Sikorsky S-61N (N4606G), Oakland, CA, incident, minor damage
- [NTSB OAK67A0043](https://openairdocs.org/ntsb/OAK67A0043), Oct 11, 1966: Sikorsky S-61N (N4606G), Mountain View, CA, substantial damage
- [NTSB OAK66A0054](https://openairdocs.org/ntsb/OAK66A0054), Jun 6, 1966: Sikorsky S-61N (N4606G), San Francisco, CA, substantial damage

## FAA accident and incident reports (10)

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [Accident 20220901012339A](https://openairdocs.org/incident/20220901012339A), Sep 1, 2022: Sikorsky S-61N (N617CK), Shady Cove, OR, Substantial damage. PIC stated that they were approximately 200' AGL and had just lifted off with a load of chokers as part of a logging operation. The pilot heard a pop pop pop…
- [Accident 20220222001029A](https://openairdocs.org/incident/20220222001029A), Feb 22, 2022: Sikorsky S-61N (N615CK), Kekaha, HI, Destroyed, 4 fatal. 02/22/2022: At approximately 10:20 HST an S61N, registration # N615CK, [privacy data omitted] was destroyed on ground impact at barking sands airport. The…
- [Accident 20200420022249A](https://openairdocs.org/incident/20200420022249A), Apr 20, 2020: Sikorsky S-61N (N908CH), Camp Dwyer, Substantial damage. On 20 April, 2020, at approximately 0800 local time, a Sikorsky S-61N, N908CH, experienced a loss of control in flight and rolled on its side during an…
- [Incident 20180919019159I](https://openairdocs.org/incident/20180919019159I), Sep 19, 2018: Sikorsky S-61N (N906CH), Fort Pierce, FL, No damage. Flying north bound about 15MN from fpr airport at 1500FT, MSL the aircraft hit a bird (seagull). The brid hit below the center windshield near the ILS antenna.…
- [Accident 20160906018209A](https://openairdocs.org/incident/20160906018209A), Sep 6, 2016: Sikorsky S-61N (N805AR), Palm Bay, FL, Destroyed, 3 fatal. On September 6, 2016, at approximately 1340 eastern daylight time, a Sikorsky S-61N, N805AR, was destroyed when it impacted the ground near Palm Bay, Florida.…
- [Incident 20120229011311I](https://openairdocs.org/incident/20120229011311I), Feb 29, 2012: Sikorsky S-61N (N408WC), Minor damage. N408WC landed at support base xenon 37AND was taxing to parking. One pilot had hands on controls the second pilot was reading afteer landing checklist. An army…
- [Accident 20080805857529A](https://openairdocs.org/incident/20080805857529A), Aug 5, 2008: Skrsky S61N (N612AZ), Redding, CA, Destroyed, 9 fatal. On August 5, 2008, at approximately 1940 pacific dayligt time, a Sikorsky S-61N helicopter, N612AZ, operated by carson helicopter servics inc., under contract…
- [Incident 19801019075309I](https://openairdocs.org/incident/19801019075309I), Oct 19, 1980: Skrsky S61A (N4240S), Mesa, AZ, Minor damage. Rotor blast damaged a small parked aircraft, controls not locked. Helicopter pilot felt clearance was sufficient.
- [Incident 19800801067189I](https://openairdocs.org/incident/19800801067189I), Aug 1, 1980: Skrsky S61A (N4240S), Portland, PA, Minor damage. Tow line for magnetometer broke causing it to fall to the ground.
- [Accident 19750722038639A](https://openairdocs.org/incident/19750722038639A), Jul 22, 1975: Skrsky S61L (N301Y), Garden Valley, ID, Substantial damage. Ext load logging opn. Lost ctl after sudden pitch up drg transition fm hover to fwd flt.

## Service difficulty reports (287, newest 50)

As reported by operators and repair stations, by the model named in the report.

- [SDR JTAA20260504001](https://openairdocs.org/sdr/JTAA20260504001), May 4, 2026: TRANSMISSION. FOD. DURING FLIGHT HAD LOW TRANSMISSION PRESSURE AND ELS SYSTEM KICKED ON. FOUND MGB LINER MATERIAL IN CHIP DETECTOR SCREEN OF MGB.
- [SDR 2026F00097](https://openairdocs.org/sdr/2026F00097), May 4, 2026: TRANSMISSION. FOD. DURING FLIGHT HAD LOW TRANSMISSION PRESSURE AND ELS SYSTEM KICKED ON. FOUND MGB LINER MATERIAL IN CHIP DETECTOR SCREEN OF MGB.
- [SDR 2024F00051](https://openairdocs.org/sdr/2024F00051), Mar 4, 2024: CABLE. CHAFED. #1 ENGINE FIRE LIGHT ILLUMINATED IN FLIGHT. R&R'D ENGINE FIRE LOOP CABLE.
- [SDR 2024FA0000139](https://openairdocs.org/sdr/2024FA0000139), Feb 7, 2024: DAMPER. CRACKED. AFTER THE SECOND GROUND TURN ON A/C 61703 FEBRUARY 06, 2024 THE DAMPER LISTED ABOVE CRACKED AT THE INBOARD SIDE OF THE DAMPER HOUSING. THE AIRCRAFT PERFORMED ON
- [SDR R9EA202008110101](https://openairdocs.org/sdr/R9EA202008110101), Jun 11, 2021: PUMP. FAILED. DURING EXTERNAL LIFT OPERATIONS AUX SERVO LIGHT ILLUMINATED AND LOST ALL AUX SERVO PRESSURE. AIRCRAFT RELEASED EXTERNAL LOAD IN HARBOR AND MADE SAFE LANDING AT 
- [SDR R9EA20200811001](https://openairdocs.org/sdr/R9EA20200811001), Jun 7, 2020: GEARBOX. FAILED. DURING FLIGHT, AIRCREW NOTICED LOW OIL PRESSURE TO THE MAIN GEAR BOX, NO LIGHT OR OTHER INDICATIONS NOTED. AIRCRAFT RETURNED TO BASE WITH NO OTHER DISCREPANCIES
- [SDR JTAA2019101120001](https://openairdocs.org/sdr/JTAA2019101120001), Oct 11, 2019: TRANS RECTIFIER. FAILED. ENCOUNTERED SMOKE IN THE COCKPIT WITH ACCOMPANYING DC GEN AND RECTIFIER WARNING LIGHTS ILLUMINATED. IDENTIFIED TRANSFORMER RECTIFIER WINDINGS HAD OVERHEATED AND
- [SDR R9EA20200306001](https://openairdocs.org/sdr/R9EA20200306001), Sep 17, 2019: CONNECTOR. CONTAMINATED. MAIN LANDING GEAR DID NOT RETRACT WHEN SELECTED. (ACTION TAKEN) MOISTURE FOUND IN MAIN LANDING GEAR PUMP MOTOR CANNON PLUG. CLEANED PLUG AND PERFORMED MAIN LAND
- [SDR JTAA201904230001](https://openairdocs.org/sdr/JTAA201904230001), Apr 19, 2019: CONNECTOR. MELTED. EXPERIENCED AN ELECTRICAL FAILURE THAT RESULTED IN 6 CIRCUIT BREAKERS TRIPPED AND ELECTRICAL CONNECTOR J3/P3 ON THE AVIONICS RELAY BOX TO SHOW MELTING ON ONE EN
- [SDR JTAA2018081000119](https://openairdocs.org/sdr/JTAA2018081000119), Aug 9, 2018: FIRE WARNING. FALSE ACTIVATION. CARRYING AN EXTERNAL LOAD, A NR 2 ENGINE FIRE INDICATED. THE LOAD WAS SET BACK DOWN AND AIRCRAFT LANDED. INSPECTED THE NR 2 ENGINE AND NO EVIDENCE OF FIRE. DETE
- [SDR 2018F00079](https://openairdocs.org/sdr/2018F00079), Jun 15, 2018: LINE. CRACKED. MAIN ROTOR GEARBOX EMERGENCY OIL LINE WAS LOSING OIL CAUSING INDICATION OF LOW GEARBOX OIL PRESSURE. THIS WAS CAUSE FOR AN EMERGENCY LANDING.
- [SDR 39LA20170702173](https://openairdocs.org/sdr/39LA20170702173), Jul 2, 2017: LINER. WORN. WHEN USING BRAKES, AIRCRAFT CONTINUED TO ROLL. REMOVED AND REPLACED THE WORN BRAKE LINERS IAW MM 32-43-1. BLED BRAKE SYSTEM IAW MM 32-43-0. OPS CHECKED GOOD.
- [SDR JYER20161207001](https://openairdocs.org/sdr/JYER20161207001), Dec 7, 2016: BEARING. MISMANUFACTURED. DURING ROUTINE OVERHAUL OF ACCESSORY DRIVE GEARBOX, THE LOWER BEARING INSTALLED ON BEVEL PINION GEAR WAS FOUND TO HAVE WHAT APPEARS TO BE A SMALLER BALL IN THE 
- [SDR 2016FA0000605](https://openairdocs.org/sdr/2016FA0000605), Dec 6, 2016: A/C PACK. INOPERATIVE. DURING A TRAINING FLIGHT, THE AUXILIARY SERVO SYSTEM WAS SECURED "OFF" WITH THE PILOT'S COLLECTIVE SWITCH DURING FLIGHT FOR TRAINING PURPOSES. AFTER THE MANEUVE
- [SDR 39LA20161205171](https://openairdocs.org/sdr/39LA20161205171), Dec 5, 2016: DOOR. DEPARTED. DURING CRUISE FLIGHT, THE CREW HEARD AND FELT A LOUD BANG AND NOTICED THAT THE PASSENGER AIRSTAIR DOOR HAD DEPARTED THE AIRCRAFT. AIRCRAFT CONTINUED FLIGHT AND 
- [SDR 39LA20161006170](https://openairdocs.org/sdr/39LA20161006170), Oct 6, 2016: WINDOW. DEPARTED. DURING CRUISE, THE CO-PILOT NOTICED THE SLIDING WINDOW ON THE RIGHT SIDE HAD DETACHED FROM THE AIRCRAFT AND WAS MISSING. LANDING WAS NORMAL. REMOVED REMAINING S
- [SDR 39LA20160914169](https://openairdocs.org/sdr/39LA20160914169), Sep 14, 2016: ENGINE. FLAMED OUT. UPON TAKEOFF, THE CREW REPORTED THAT THE NR 2 ENGINE SHUTDOWN. UPON LANDING, THE AIRCRAFT WAS SHUTDOWN WHILE THE PASSENGERS WERE EVACUATED. MAINTENANCE PERFORME
- [SDR 39LA20160906168](https://openairdocs.org/sdr/39LA20160906168), Sep 6, 2016: ENGINE. FLAMED OUT. WHILE 4.3 HOURS INTO A CONOP, THE CREW HAD JUST TAKEN OFF ENROUTE. WHILE TRANSITIONING TO FORWARD FLIGHT AT APPROXIMATELY 75 FT, THE CREW FELT THE ACFT YAW LT, 
- [SDR JTAA2016F00175](https://openairdocs.org/sdr/JTAA2016F00175), Aug 26, 2016: ENGINE. DAMAGED. THE SIC NOTICED THE ENGINE INSTRUMENT INDICATIONS WERE DISPLAYING IRREGULAR INDICATIONS WHILE OVER A LAKE FILLING A WATER BUCKET. NR 2 ENGINE ROLLED BACK TO IDL
- [SDR 39LA20160825167](https://openairdocs.org/sdr/39LA20160825167), Aug 25, 2016: PUMP. LEAKING. REPORTED A VERY INTENSE FUEL ODOR RETURNING DEPARTURE AT THE END OF AN 8 HOUR CONOP. DURING REFUELINGS THROUGHOUT THE DAY, OCCASIONAL DROPS OF FUEL WERE NOTICED
- [SDR 39LA20160817166](https://openairdocs.org/sdr/39LA20160817166), Aug 17, 2016: DRAIN. PLUGGED. DURING THE FIRST 3.6 HRS OF FLIGHT, 7 LEGS REPORTED, THE CREW DETECTED AN OVERWHELMING ODOR OF JET FUEL IN THE COCKPIT AND CABIN DURING CLIMBS AND DESCENTS. THE
- [SDR 39LA20160512156](https://openairdocs.org/sdr/39LA20160512156), May 12, 2016: FIRE LOOP. FAULTY. AFTER TAKEOFF, THE NR 2 ENG FIRE INDICATOR & FIRE T HANDLE ILLUMINATED. THE CREW CHIEF ON BOARD VISUALLY VERIFIED THAT NO FIRE EXISTED. NO EMER WAS DECLARED & T
- [SDR 39LA20160426155](https://openairdocs.org/sdr/39LA20160426155), Apr 26, 2016: SKIN PANEL. CORRODED. INTERGRANULAR CORROSION FOUND ON AFT LOWER SKIN OF ACFT, LOCATED AT AREA OF FS 292 - 323, WL 85, BL 35R OUTER RT SIDE OF AFT FUEL BAY. CORROSION MOSTLY LEVEL 1.
- [SDR 39LA20160414154](https://openairdocs.org/sdr/39LA20160414154), Apr 14, 2016: HYDRAULIC LINE. BLOWN. AFTER TAKEOFF & DURING CLIMB OUT, THE PRIMARY HYDRAULICS BEGAN TO FLUCTUATE. THE MASTER CAUTION & PRIMARY HYD LIGHT ILLUMINATED. EMERGENCY PROCEDURES PERFORMED.
- [SDR 39LA20160412153](https://openairdocs.org/sdr/39LA20160412153), Apr 12, 2016: RELAY. FAILED. AFTER LANDING, AN ODOR OF ELEC BURNING WAS DETECTED IN THE COCKPIT. THERE WERE NO UNUSUAL INDICATIONS ON COCKPIT GAUGES TO INDICATE ELEC MALFUNCTION. ACFT EMER 
- [SDR 39LA20160410152](https://openairdocs.org/sdr/39LA20160410152), Apr 10, 2016: RELAY. BURNED OUT. ON SHORT FINAL, THE ALTERNATE BATTERY OFF LIGHT ILLUMINATED. THERE WAS ALSO A SMELL OF BURNING PLASTIC. LANDING ACCOMPLISHED WITH NO OTHER PROBLEMS. TROUBLE SHO
- [SDR JYER20160209001](https://openairdocs.org/sdr/JYER20160209001), Feb 9, 2016: BEARING. WORN. ENGINE WAS REMOVED FROM AIRCRAFT DUE TO AN IN FLIGHT NR 2 ENGINE CHIP LIGHT. THE FRONT FRAME ACCESSORY DRIVE GEARBOX CHIP WAS REMOVED AND DETERMINED TO BE THE S
- [SDR 39LA20160204151](https://openairdocs.org/sdr/39LA20160204151), Feb 4, 2016: ACCESS PANEL. MISSING. THE FLIGHT CREW, DURING POST FLIGHT INSPECTION, DISCOVERED THAT THE AFT LT TRANSMISSION OIL COOLER ACCESS PANEL WAS MISSING.
- [SDR CA160126012](https://openairdocs.org/sdr/CA160126012), Jan 24, 2016: BLADE. CRACKED. (CAN) POST FLIGHT INSPECTION REVEALED A CRACK IN THE UNDER SIDE AND AFT FACE OF THE POCKET SKIN OF THE BLADE AT APPROXIMATELY 48" OTBD OF THE CUFF. MFG HAS BEEN
- [SDR 39LA20151206150](https://openairdocs.org/sdr/39LA20151206150), Dec 6, 2015: SERVO. LEAKING. DURING CRUISE FLIGHT, THE FLIGHT CREW SMELLED AN ODOR. THE CREW CHIEF DISCOVERED A HYD LEAK, THE DECISION WAS MADE TO DIVERT. THE FLIGHT CONTINUED WITHOUT FURTH
- [SDR 39LA20151117148](https://openairdocs.org/sdr/39LA20151117148), Nov 17, 2015: UNKNOWN. FUMES. APPROXIMATELY 2 MINUTES AFTER TAKEOFF, STRONG FUEL SMELL IN COCKPIT. FUMES APPEARED TO BE COMING THROUGH CABIN FLOOR, RETURNED.
- [SDR 39LA20151113149](https://openairdocs.org/sdr/39LA20151113149), Nov 13, 2015: FIRE LOOP. FAILED. ON FINAL APPROACH, THE NR 1 ENG FIRE WARNING LIGHT ILLUMINATED. THERE WAS NO FIRE OR OTHER INDICATIONS OF A FIRE, A NORMAL LANDING WAS PERFORMED. REPLACED NR 1 
- [SDR 39LA20150910144](https://openairdocs.org/sdr/39LA20150910144), Sep 10, 2015: ACCESS PANEL. MISSING. DURING POST FLIGHT INSPECTION, THE FLIGHT CREW DISCOVERED THAT THE LT SIDE TRANSMISSION MX PANEL WAS MISSING. REPLACED PANEL, REMOVED FROM THAT WAS INSPECTED & 
- [SDR 39LA20150903143](https://openairdocs.org/sdr/39LA20150903143), Sep 3, 2015: FIRE LOOP. OUT OF POSITION. DURING HOVER THE NR 1 ENG FIRE LIGHT ILLUMINATED, FALSE FIRE WARNING. REPOSITIONED FIRE LOOP SENSOR AWAY FROM NR 1 ENG EXHAUST PIPE IAW MM 4045-80 CHP 26.
- [SDR CA150827012](https://openairdocs.org/sdr/CA150827012), Aug 26, 2015: DAMPER. FAILED. (CAN) PERFORMED A MAIN ROTOR DAMPER TIMING TEST, WE HAVE FOUND THE DAMPER TO FAIL. UPON FURTHER INVESTIGATION IT WAS REMOVED DUE TO EXCESSIVE OIL LEAKAGE. THE D
- [SDR 39LA20150823141](https://openairdocs.org/sdr/39LA20150823141), Aug 23, 2015: ELEC CONNECTOR. SHORTED. DURING CRUISE THE FLIGHT CREW NOTICED AN ODOR THAT SMELLED LIKE AN ELEC FIRE. THE MASTER CAUTION FOR THE NR ONE GEN ILLUMINATED WITH THE AFCS SIMULTANEOUSLY SHU
- [SDR 39LA20150713140](https://openairdocs.org/sdr/39LA20150713140), Jul 13, 2015: GEARBOX. LOW PRESSURE. DURING CRUISE FLIGHT THE MASTER CAUTION WARNING LIGHT ILLUMINATED FOR THE TRANSMISSION LOW OIL PRESS WITH ASSOCIATED PRESS GAUGE READING OF 20 PSI. AN OFFSITE L
- [SDR CA150708013](https://openairdocs.org/sdr/CA150708013), Jul 7, 2015: PUMP. SEIZED. (CAN) DURING PREFLIGHT INSPECTION, MAIN ROTOR COULD NOT BE MANUALLY ROTATED IN THE DIRECTION OF ROTATION. UTILITY HYDRAULIC PUMP WAS FOUND TO BE SEIZED. AFTER P
- [SDR 39LA20150701139](https://openairdocs.org/sdr/39LA20150701139), Jul 1, 2015: UNKNOWN. MALFUNCTIONED. AFTER LANDING & DURING TAXI, NORMAL BRAKING WOULD NOT STOP THE ACFT.
- [SDR JYEA2015FA0000211](https://openairdocs.org/sdr/JYEA2015FA0000211), May 13, 2015: PRESSURE SWITCH. INTERMITTENT. WHEN TESTING HYD SYS USING MOGEN AND SELECTING PRIMARY OFF, IT WOULD NOT. AFTER THE THIRD SELECTION TO OFF, IT FINALLY TURNED OFF SECURING PRESSURE TO PRIMARY W
- [SDR 39LA20150329132](https://openairdocs.org/sdr/39LA20150329132), Mar 29, 2015: WINDOW. DEPARTED. DURING INITIAL CLIMB THE CREW CHIEF NOTIFIED THE PILOT THAT THE LT EMER EXIT WINDOW DEPARTED THE ACFT. INSTALLED SERVICEABLE WINDOW IAW MM CHAPTER 52.
- [SDR 39LA20150221108](https://openairdocs.org/sdr/39LA20150221108), Feb 21, 2015: SWITCH. FAILED. DURING FINAL APPROACH THE NR 2 ENG FIRE WARNING LIGHT IN THE T HANDLE WAS FLICKERING & STAYED ON AFTER LANDING. FOUND FIRE WARNING TEST SWITCH INOPERATIVE. R & 
- [SDR 39LA20150220107](https://openairdocs.org/sdr/39LA20150220107), Feb 20, 2015: CONNECTOR. DIRTY. DURING FINAL APPROACH THE NR 2 ENG FIRE WARNING LIGHT IN THE T HANDLE WAS FLICKERING WITH NO VISUAL SIGNS OF FIRE. CLEANED FORE & AFT ENG DECK FIRE LOOP CONNECT
- [SDR 39LA20141221104](https://openairdocs.org/sdr/39LA20141221104), Dec 21, 2014: ENGINE. MALFUNCTIONED. DURING LANDING AT A 10 FOOT HOVER ACFT EXPERIENCED A VIOLENT SHUTTER & A LOUD GRINDING SOUND FROM THE NR 1 ENG. T5 WENT ABOVE 958 DEGREES & THE ENG SHUTDOWN AUT
- [SDR CA141024019](https://openairdocs.org/sdr/CA141024019), Oct 24, 2014: GEARBOX. MAKING METAL. (CAN) PRIOR TO TAKEOFF FOR FIRST FLIGHT OF THE DAY, THE MAIN GEAR BOX CHIP LIGHT ILLUMINATED. HELICOPTER WAS SHUTDOWN AND METAL WAS FOUND IN THE OIL STRAINER "C
- [SDR 39LA20141023103](https://openairdocs.org/sdr/39LA20141023103), Oct 23, 2014: CONTROL PANEL. SHORTED. DURING CRUISE FLIGHT, SMOKE & ELEC FIRE SMELL ROSE NEAR THE CTR OF THE WINDSCREEN. FLIGHT CREW ELECTED TO RETURN TO DEPARTURE AIRPORT & SAFELY LANDED. UPON INSP
- [SDR 39LA2014072382](https://openairdocs.org/sdr/39LA2014072382), Jul 23, 2014: FIRE WARNING. FALSE ACTIVATION. DURING CRUISE FLIGHT THE NR 1 ENG FIRE WARNING LIGHT ILLUMINATED INTERMITTENTLY. IT WAS DETERMINED TO BE A FALSE FIRE WARNING & LANDED WITHOUT FURTHER INCIDENT.
- [SDR CA140624003](https://openairdocs.org/sdr/CA140624003), Jun 24, 2014: SHAFT. DAMAGED. (CAN) DURING MAIN GEAR BOX O/H, AND SUBSEQUENT INSPECTION OF THRU-SHAFT, RUN-OUT CHECK INDICATED A 0.012" BULGE AT THE FORWARD END. THIS MAY HAVE OCCURRED DURIN
- [SDR 39LA2014061171](https://openairdocs.org/sdr/39LA2014061171), Jun 11, 2014: CONTROL PANEL. FAILED. DURING TAKEOFF, THE PILOTS RADIO WAS INTERMITTENT DURING TRANSMISSIONS. RETURNED WITHOUT INCIDENT. REMOVED AUDIO CONTROL PANEL PN N301A-000, SN 61424 & INSTALLE
- [SDR CA140424014](https://openairdocs.org/sdr/CA140424014), Apr 17, 2014: HOUSING. CRACKED. (CAN) CRACKS WERE FOUND ON QTY 4 OF THE LUGS THAT ATTACH THE TOP HOUSING TO THE MAIN GEAR BOX. THE CRACKS EXTEND FROM OTBD EDGE TO SCREW HOLES THAT ATTACH A REW

All 287: https://openairdocs.org/model/sikorsky-s-61n/reports.md

## STCs that may be installed (OpenAirDocs) (107, first 50)

Approved for this model: the STC's model list names it on its data sheet, or a series that includes it. In force first, then newest. The registry doesn't record which STCs an aircraft has.

- [STC SR04465NY](https://openairdocs.org/stc/SR04465NY): Installation of the iPad Mount. Avio Design Group Inc
- [STC SR01858SE](https://openairdocs.org/stc/SR01858SE): Manufacture of the Isolair, Inc., Eliminator II Model 4600-S61 Fire Fighting System. Isolair Inc
- [STC SR00218IB](https://openairdocs.org/stc/SR00218IB): Installation of the Cockpit Door. Croman Corporation
- [STC SR00220IB](https://openairdocs.org/stc/SR00220IB): Installation of Replacement Avionics Shelves. Croman Corporation
- [STC SR00283SE](https://openairdocs.org/stc/SR00283SE): Removal of a 50 inch section from the forward fuselage between stations 110 and 160 and reinstallation of forward cabin with associated fabricated parts. Croman Corporation
- [STC SR00427SE](https://openairdocs.org/stc/SR00427SE): Fabrication and installation of a Helipro Model H9661N01-01, -03, -05, -07, -51, -53, -55, -57, -59 or -61 logging utility system. Croman Corporation
- [STC SR00814SE](https://openairdocs.org/stc/SR00814SE): Fabrication of reinforcement kit - aft fuselage station 493. For model S61A, applies to S/N 61094. For model S61NM, applies to S/N 66454. Croman Corporation
- [STC SR01264SE](https://openairdocs.org/stc/SR01264SE): Fabrication of Helipro replacement windshields. Croman Corporation
- [STC SH3319NM](https://openairdocs.org/stc/SH3319NM): Installation of Precise Flight Pulselite Control Unit in the Landing /Taxi Recognition Visual Control Light system,. Precise Flight Inc
- [STC SR02279AK](https://openairdocs.org/stc/SR02279AK): Installation of dual Rockwell Collins FDS 2000 flight displays, dual AHS 3000 attitude and heading reference systems, dual Garmin GNS 530 navigation systems and supporting avionics equipment. Croman Corporation
- [STC SR09236RC](https://openairdocs.org/stc/SR09236RC): Installation of a Modular Harness. Croman Corporation
- [STC SR04501CH](https://openairdocs.org/stc/SR04501CH): The certification of various configurations of cockpit side windows. CHI Aviation
- [STC SR01127SE](https://openairdocs.org/stc/SR01127SE): Modification of main rotor blade part number 61170-20201 in accordance with Master Drawing List RR 9633-08, Revision A, dated September 17, 2002, or later FAA approved revision. Retirement life for the modified main rotor blade, part number RR-61170-20201 is 21,200 total time in service. Park Technologies, LLC
- [STC SR00039IB](https://openairdocs.org/stc/SR00039IB): Installation of Coulson Aircrane Limited (CAL) Hoist Replacement Parts. Coulson Aircrane Ltd
- [STC SR09490RC](https://openairdocs.org/stc/SR09490RC): Installation of nine passenger seat configuration. McHenry Priestley Aviation LLC
- [STC SR00681SE](https://openairdocs.org/stc/SR00681SE): Fabrication of Onboard Systems Model 200-243-00 or 200-243-01 Cargo Hook Load Weigh System. Onboard Systems International
- [STC SR01552SE](https://openairdocs.org/stc/SR01552SE): Fabrication and installation of an external aerial liquid dispensing tank. Carson Helicopters Inc
- [STC SR04607NY](https://openairdocs.org/stc/SR04607NY): Installation of Garmin GTX Transponder System. Maxcraft Avionics Ltd
- [STC SR04609NY](https://openairdocs.org/stc/SR04609NY): Installation of Garmin HTAWS (Helicopter Terrain Awareness Warning System). Maxcraft Avionics Ltd
- [STC SR04483CH](https://openairdocs.org/stc/SR04483CH): Installation of NASI NREM18M Air Conditioning Module. National Aircraft Service Inc. (NASI)
- [STC SR00925DE](https://openairdocs.org/stc/SR00925DE): Installation of Garmin GTX 335/335R and GTX345/345R transponders to provide ADS-B Out and In functionality. Peregrine
- [STC SR04401NY](https://openairdocs.org/stc/SR04401NY): Increase of Out of Ground Effect (OGE) Hover Performance. Carson Helicopters Inc
- [STC SR04122NY](https://openairdocs.org/stc/SR04122NY): The Installation of Carson Helicopters, Inc. Composite Tail Rotor Blade and Pitch Sleeve, part number 428-600-1,. Carson Helicopters Inc
- [STC SR02596SE](https://openairdocs.org/stc/SR02596SE): Installation of Olympic Aero Services, Inc. Additional Telemetry Unit (ATU). OLYMPIC AERO SERVICES INC
- [STC SR02487NY](https://openairdocs.org/stc/SR02487NY): Increased Category A Performance for the Sikorsky S-61L, S-61N and S-61NM Helicopters. Carson Helicopters, Inc
- [STC SR02583SE](https://openairdocs.org/stc/SR02583SE): Installation of a 9 passenger seat configuration for side-facing seats. Croman Corporation
- [STC SR02507NY](https://openairdocs.org/stc/SR02507NY): Installation of a 600 pound capacity Goodrich AC rescue hoist system P/N 44311-10-2. Carson Helicopters, Inc
- [STC SR03664NY](https://openairdocs.org/stc/SR03664NY): Installation of the Engine Inlet Barrier Filter System (IBFS). Coulson Aircrane Ltd
- [STC SR02267SE](https://openairdocs.org/stc/SR02267SE): Fabrication of replacement transmission fittings. Croman Corporation
- [STC SR02394AK](https://openairdocs.org/stc/SR02394AK): Replacement of existing landing and/or hover light bulbs with Light Emitting Diode (LED) lighting system. Seaplanes North LLC
- [STC SR03310CH](https://openairdocs.org/stc/SR03310CH): Installation of NASI Air Conditioning Module. National Aircraft Service Inc
- [STC SH5125NM](https://openairdocs.org/stc/SH5125NM): Installation of Croman 10,000 lbs. cargo sling system and associated fuselage mounting hardpoints. Croman Corporation
- [STC SR02501LA](https://openairdocs.org/stc/SR02501LA): Removal of the Bendix 30E20-11-C 300 Amp Starter Generator and installation of the AMETEK Aerospace MG105A-1, 300 Amp Starter Generator. Carson Helicopters, Inc
- [STC SR01426SE](https://openairdocs.org/stc/SR01426SE): Fabrication and installation of components for a left seat pilot-in-command operation. Croman Corporation
- [STC SR01480SE](https://openairdocs.org/stc/SR01480SE): Fabrication and installation of an external firefighting tank. Carson Helicopters, Inc
- [STC SR02327AK](https://openairdocs.org/stc/SR02327AK): Manufacture side-facing seat mounting structure. Carson Helicopters, Inc
- [STC SR00319SE](https://openairdocs.org/stc/SR00319SE): Modification of Part Number S6137-23009-6 main transmission rear cover per. Croman Corporation
- [STC SR01534SE](https://openairdocs.org/stc/SR01534SE): Installation of the transmission input modification to the main gear box. Croman Corporation
- [STC SR02248SE](https://openairdocs.org/stc/SR02248SE): Installation of a Supplemental Lighting System. Aviation Specialties Unlimited Inc
- [STC SR01853NY](https://openairdocs.org/stc/SR01853NY): Installation of a SkyTrac ISAT-100 / ISAT-200 Airborne Position/Data Communicator. SkyTrac Systems Ltd
- [STC SR00465SE](https://openairdocs.org/stc/SR00465SE): Installation of a Mechanical Specialties Model 611 cargo hook. Mechanical Specialties Inc
- [STC SR09232RC](https://openairdocs.org/stc/SR09232RC): Installation of a ground inverter. Vector Aerospace Helicopter Services USA Inc
- [STC SR09233RC](https://openairdocs.org/stc/SR09233RC): Installation of a Solid State Voltage Regulator. Vector Aerospace Helicopter Services USA Inc
- [STC SR02190SE](https://openairdocs.org/stc/SR02190SE): Installation of steel transmission fitting fabricated in accordance with Croman Drawing S-6120-62113-CRO41, Revision D, dated January 8, 1982, or later Federal Aviation Administration (FAA) approved revision; installed in accordance with Croman Installation Instructions S-6120-62113-CRO41-Inst, Revision IR, dated August 10, 2011, or later FAA- approved revision. Croman Corporation
- [STC SR01771NY](https://openairdocs.org/stc/SR01771NY): Increase of Out of Ground Effect (OGE) Hover Performance. Carson Helicopters Inc
- [STC SR02335AK](https://openairdocs.org/stc/SR02335AK): Installation of two or three tank fuel quantity indicating systems when installed. Carson Helicopters, Inc
- [STC SR02336AK](https://openairdocs.org/stc/SR02336AK): Installation of an Integrated Cockpit Display System (ICDS) with an Attitude and Heading Reference System (AHRS) for Dual Pilot Instrument Flight Rules Category A and B operation in accordance with Vector Aerospace Helicopter Services Inc. Master Drawing List , HP 61-34-33-105, Revision A, dated February 28, 2011, or later FAA approved revision. Carson Helicopters, Inc
- [STC SR02999NY](https://openairdocs.org/stc/SR02999NY): Installation of Auxiliary External Torque Gauge and External Load Meter in accordance with VIH Aerospace Inc., Master Document List VS61-0715J-MDL, Revision A, Dated January 24, 2011, approved by Transport Canada Civil Aviation (TCAA) on February 15, 2011, or later TCCA approved revisions. VIH Aerospace Inc
- [STC SR02087SE](https://openairdocs.org/stc/SR02087SE): Limit the standard passenger seating configuration to 19 or less on the Sikorsky S-61N rotorcraft. Croman Corporation
- [STC SR02832CH](https://openairdocs.org/stc/SR02832CH): Installation of Brownlee seat track and SICMA TSO C39b or C127a Seats. VIH Cougar Helicopters Inc

All 107: https://openairdocs.org/model/sikorsky-s-61n/stcs.md

## PMA parts (OpenAirDocs) (over 1,000, first 50)

Current parts manufacturer approvals (PMA): parts the FAA has approved companies to make as replacements or modifications. Each record lists its models as free text; OpenAirDocs matched them to this model on its data sheet, so check the FAA record before relying on it. Newest first.

- [S6135-20059-106ACD](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID197460292520260806140631.0001): Packing. Aircraft Component Design LLC · PMA PQ2138NE · Replaces S6135-20059-106 · Jun 30, 2026
- [S6135-20059-109ACD](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID193521811720260806140631.0001): Packing. Aircraft Component Design LLC · PMA PQ2138NE · Replaces S6135-20059-109 · Jun 30, 2026
- [S6135-20059-103ACD](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID192315876020260806140630.0001): Packing. Aircraft Component Design LLC · PMA PQ2138NE · Replaces S6135-20059-103 · Jun 30, 2026
- [S6135-20059-105ACD](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID184486466020260806140631.0001): Packing. Aircraft Component Design LLC · PMA PQ2138NE · Replaces S6135-20059-105 · Jun 30, 2026
- [S6135-20059-101ACD](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID183102410220260806140630.0001): Packing. Aircraft Component Design LLC · PMA PQ2138NE · Replaces S6135-20059-101 · Jun 30, 2026
- [S6135-20059-107ACD](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID172759073920260806140631.0001): Packing. Aircraft Component Design LLC · PMA PQ2138NE · Replaces S6135-20059-107 · Jun 30, 2026
- [S6135-20059-102ACD](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID143172029820260806140630.0001): Packing. Aircraft Component Design LLC · PMA PQ2138NE · Replaces S6135-20059-102 · Jun 30, 2026
- [S6135-20697-1ACD](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID131002440420260806140632.0001): Packing. Aircraft Component Design LLC · PMA PQ2138NE · Replaces S6135-20697-1 · Jun 30, 2026
- [RS40C1A390000](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID172857139820260305155758.0001): HOSE ASSY. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces SS40C1A390000 · Feb 19, 2026
- [R1615-30113-005](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID150742166620251117194918.0001): SHIM. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S1615-30113-005 · Oct 22, 2025
- [RS4059-12-524](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID118634438020250916191108.0001): SPACER. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces SS4059-12-524 · Sep 2, 2025
- [RS40CT27D146185](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID136614728920250908142033.0001): HOSE ASSY. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces SS40CT27D146185 · Aug 29, 2025
- [MDL TD 031851](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID126524348320250508133547.0001): VA-1A( )AndAccessories. Electronics International Inc · PMA PQ0088NM · Modification part · Apr 10, 2025
- [R6135-20125-1](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID147330334320250303213556.0001): PLATE. Rotair Aerospace Corporation624 · PMA PQ0781NE · Replaces S6135-20125-1 · Feb 27, 2025
- [R6120-60916-9](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID139878254820250303213601.0001): FITTING ASSY. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S6120-60916-9 · Feb 20, 2025
- [RM-307-SA7](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID181256324620250130180912.0001): Outboard Mounting Assy. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces LM-307-SA7 · Jan 10, 2025
- [RM-307-SA6](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID145149444420250130171339.0001): Inboard Mounting Assy. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces LM-307-SA6 · Jan 10, 2025
- [R6188-20037-26](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID173764954820250106173101.0001): Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S6188-20037-26 · Dec 9, 2024
- [R6188-20037-28](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID142943021920250106173101.0001): Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S6188-20037-28 · Dec 9, 2024
- [R1615-30113-006](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID132635522820250106173306.0001): SHIM. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S1615-30113-006 · Dec 9, 2024
- [R6188-20037-23](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID115265640620250106173101.0001): Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S6188-20037-23 · Dec 9, 2024
- [R1615-30113-007](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID114835780120250106173307.0001): SHIM. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S1615-30113-007 · Dec 9, 2024
- [R6188-20037-21](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID112521366620250106173100.0001): Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S6188-20037-21 · Dec 9, 2024
- [R6135-66661-0](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID157007349120241024163556.0001): LINER. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S6135-66661-0 · Oct 21, 2024
- [R6135-20241-2](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID124935081120240815113906.0001): BUSHING. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S6135-20241-2 · Aug 1, 2024
- [R6135-20241-2](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID175185429520240726140503.0001): BUSHING. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S6135-20241-2 · May 21, 2024
- [SB5063-101ACD](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID173472979620230503123336.0001): Bearing, Spherical Plain, Self-Aligning. Aircraft Component Design LLC · PMA PQ2138NE · Replaces SB5063-101 · Apr 26, 2023
- [R6165-61517-101](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID115212629020230331175557.0001): Housing. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S6165-61517-101 · Mar 24, 2023
- [200-243-00200-243-01](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID100956162220220811112052.0001): E84 Load Weigh System, Sikorsky S-61. Onboard Systems International · PMA PQ0055NM · Modification part · Jul 28, 2022
- [SB2501-1ACD](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID187843990020220713192317.0001): Bearing, Inner Race Needle. Aircraft Component Design LLC · PMA PQ2138NE · Replaces SB2501-1 · Jul 8, 2022
- [R6135-20061](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID125048476520220616191118.0001): Liner. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S6135-20061 · Jun 6, 2022
- [No part number](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID127063789720220809130923.0001): Aviation Devices & Electronic Components LLC (Av-DEC) · PMA PQ3846SW · May 10, 2022
- [No part number](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID159924074320220809102553.0001): Aviation Devices & Electronic Components LLC (Av-DEC) · PMA PQ3846SW · Apr 18, 2022
- [R6126-50101-3](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID132576167820220405150347.0001): Rib. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S6126-50101-3 · Mar 25, 2022
- [R6126-50101-5](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID105703161620220405150348.0001): Rib. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces S6126-50101-5 · Mar 25, 2022
- [AG844000-15](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID137281346620220408135811.0001): Gasket – UHF/VHF Antenna. Aviation Devices & Electronic Components, LLC · PMA PQ03846SW · Modification part · Feb 8, 2022
- [AG728000-52](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID104771530620220408135729.0001): Gasket – Satcom Antenna. Aviation Devices & Electronic Components, LLC · PMA PQ03846SW · Modification part · Jan 26, 2022
- [AG627000-23](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID186622917920220408135709.0001): Gasket – Marker Beacon. Aviation Devices & Electronic Components, LLC · PMA PQ03846SW · Modification part · Dec 15, 2021
- [R61200-72537-104](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID315302721202112281301460.0001): Plate. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces 61200-72537-104 · Dec 7, 2021
- [R61200-72537-109](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID288630625120211228130148.0001): Plate. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces 61200-72537-109 · Dec 7, 2021
- [AG627000-12](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID134043999220220408140248.0001): Gasket – Marker Beacon Antenna. Aviation Devices & Electronic Components, LLC · PMA PQ03846SW · Modification part · Nov 17, 2021
- [AG358000-08](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID104102772720220408135823.0001): Gasket – ELT Antenna. Aviation Devices & Electronic Components, LLC · PMA PQ03846SW · Modification part · Nov 17, 2021
- [RS5086-05](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID872606088820211025121459.0001): Nut. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces SS5086-05 · Sep 27, 2021
- [RS5086-04](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID425300542220211025121438.0001): Nut. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces SS5086-04 · Sep 27, 2021
- [RS5086-06](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID324190023520211025121439.0001): Nut. Rotair Aerospace Corporation · PMA PQ0781NE · Replaces SS5086-06 · Sep 27, 2021
- [15400-15](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID993527888820211020151641.0001): Filler 28.50x1.88. Carson Helicopters, Inc. · PMA PQ4181NE · Modification part · Aug 23, 2021
- [15103-6](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID981965829020211020151614.0001): Strap (LHS). Carson Helicopters, Inc. · PMA PQ4181NE · Modification part · Aug 23, 2021
- [S6120-62276-2](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID978125076420211020151707.0001): Cover Assy. Carson Helicopters, Inc. · PMA PQ4181NE · Modification part · Aug 23, 2021
- [15500-52](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID967984721202110201516590.0001): Aft Hose Assy. Carson Helicopters, Inc. · PMA PQ4181NE · Modification part · Aug 23, 2021
- [15102-1](https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID967581602202110201516030.0001): Frame Segment Assy. Carson Helicopters, Inc. · PMA PQ4181NE · Modification part · Aug 23, 2021

All of them: https://openairdocs.org/model/sikorsky-s-61n/pma.md

## The same model under other registry codes

Amateur-built copies and renamed makers get their own codes.

- [Sikorsky/Carson Services S61N](https://openairdocs.org/model/sikorsky-carson-services-s61n): 0 registered aircraft, registry code 8142111

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OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.