FTW99FA001 · Bell 407
Petroleum Helicopters Bell 407 and Aerospatiale AS-355-F1 · Accident: midair collision en route
Event
- NTSB case
- FTW99FA001
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 1 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Aircraft 1 · Bell 407
- Aircraft type
- Bell 407
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N403PH
- Operator
- Petroleum Helicopters
- Onboard fatalities
- Unknown
- Route
- From VERMILION 331A, GM (no airport)To E. CAMERON 321A, GM (no airport)
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Midair collision
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Aircraft 2 · Aerospatiale AS-355-F1
- Aircraft type
- Aerospatiale AS-355
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N5792H
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Cameron, LA (no airport)To VERMILION 370, GM (no airport)
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Midair collision
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Pilot in command › Visual lookout, inadequate
- Pilot of other aircraft › Visual lookout, inadequate
Not plotted · Location withheld: coordinates are missing, conflicting, invalid, or have no accepted acquisition method. No substitute location has been invented.
NTSB narrative
The Bell 407 collided with an Aerospatiale AS-355-F1 while both helicopters were in cruise flight at 1,000 AGL over open ocean in the Gulf of Mexico. Both aircraft were being flown single pilot and were positioning flights between offshore platforms. The pilot of the Bell initiated an autorotation to the water and was rescued. The pilot of the Aerospatiale was fatally injured during the collision/water impact sequence and his helicopter impacted the water and sank into the ocean. Physical evidence on the recovered Bell wreckage indicated that the main rotor blades of the Aerospaciale struck the nose section of the Bell, removing the windshield, chin bubble and anti-torque pedals. The Bell's direct flight course was about 265 degrees. The Aerospatiale's direct course was about 155 degrees. The Bell pilot did not see the Aerospatiale until just before impact. The Helicopter Safety Advisory Conference (HSAC) had published a Recommended Practice (RP) in 1993 for standardized vertical separation of helicopters when flying in the offshore environment. Excerpts are: 'Helicopters operating enroute to and from offshore locations, below 3,000 feet, weather permitting, should use [the following] enroute altitudes; Magnetic Heading of 0 to 179 degrees - 750 feet or 1,750 feet, or 2,750 feet, Magnetic Heading of 180 to 359 degrees - 1,250 feet or 2,250 feet.' These recommended altitudes, if used, provide a minimum of 500 feet vertical clearance. Both operators, who are participating members in HSAC, did not have the HSAC-RP No. 93.1 included in their respective operations manuals. The RP's are recommended and not mandatory.
Probable cause
the failure of both pilots to see and avoid each other's aircraft during cruise flight. Factors were the failure of both pilots to use a known safety advisory recommendation and the failure of both operators to implement the recommendation as a company operating procedure.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record FTW99FA001
- Event ID
- 20001211X11250
- Case number
- FTW99FA001
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: a0ef6adecf0fc4736d91a405668e1c79a00556977502a9ebabe5b9a41f62a0c9; retrieved 2026-09-20T22:22:22.062Z.