Mbb BK 117 A-4 accident near Lafayette, Louisiana, May 25, 1993
On May 25, 1993 at about 2:14 pm local time, a Mbb BK 117 A-4 (helicopter), registered N401PH, was substantially damaged in an accident near Lafayette, Louisiana (Lafayette Regional airport). It was a flight of an unrecorded kind under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
CYCLIC CONTROL ROD MOVEMENT WAS RESTRICTED DUE TO IMPROPER INSTALLATION OF THE LATERAL CYCLIC CONTROL ROD BY COMPANY MAINTENANCE PERSONNEL.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 25, 1993 · about 2:14 pm local time
- Place
- Lafayette, Louisiana · Lafayette Regional
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Mbb BK 117 A-4
- Registration
- N401PH · registry record · serial 7050
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
AFTER EXPORTATION FROM CANADA, MBB BK 117 HELICOPTER WAS BEING RE-ASSEMBLED & MODIFIED FROM MODEL A-3 TO MODEL A-4; 24 HOUR/DAY SCHEDULE WAS USED TO EXPEDITE MODIFICATION FOR USE AS AIR AMBULANCE. SHIFT CHANGE OCCURRED DURING MAINTENANCE ON VERTICAL CONTROL TUBES; WHEN COMPLETED, HELICOPTER WAS FLOWN ON TEST FLIGHT. NO ANOMALIES OF FLIGHT CONTROLS WERE NOTED UNTIL FLARING TO HOVER BEFORE LANDING. PILOT SAID THAT WHILE POWER WAS BEING APPLIED, CYCLIC & PEDALS WERE MANIP- ULATED ACCORDINGLY. LEFT MOVEMENT OF CYCLIC WAS REQUIRED TO OVERCOME (ROLL &) DRIFT TO RIGHT. AT THAT TIME, THE PILOT NOTED INSUFFICIENT CYCLIC CONTROL & THE HELICOPTER CONTINUED TO ROLL RIGHT UNTIL THE MAIN ROTOR BLADES STRUCK THE GROUND. THE HELICOPTER THEN IMPACTED ON ITS RIGHT SIDE & SLID TO A STOP. AN INVESTIGATION REVEALED THE LATERAL & COLLECTIVE UPPER ADJUSTABLE CONTROL RODS HAD BEEN INTERCHANGED & COLOR CODING REPAINTED. THE INTERCHANGE OF CONTROL RODS RESULTED IN A MISRIGGED SWASHPLATE WITH A HIGHER PRESET COLLECTIVE PITCH & A RIGHT TILT OF THE SWASHPLATE.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: helicopter; rotorcraft: helicopter
- Flight time: 16,268 hours in all; 21 in this make and model; 177 in the last 90 days; 93 in the last 30 days; 9,030 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 2,128 hours
- Last inspection: 100-hour inspection, May 24, 1993; 1 hours since
- Maximum gross weight: 6,283 lb
- Seats: 5
- Landing gear: fixed
- Engine: Lycoming LTS 101-650B1 (turboshaft); 0 hours total
- Operator: Petroleum Helicopters, INC.
The flight
- Departed from: LFT at 2:06 pm
- Destination: LFT
- Runway 11, 5,201 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 060° at 5 knots
- Visibility: 7 statute miles
- Sky: broken clouds at 25,000 ft; scat at 5,000 ft
- Temperature: 77°F (25°C), dew point 66°F (19°C)
- Altimeter: 30.00 inHg
- Observation at 1:51 pm from LFT, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.