Mbb BO-105C incident near Lafayette, Louisiana, September 18, 1995
On September 18, 1995 at about 2:40 pm local time, a Mbb BO-105C (helicopter), registered N91070, was involved in an incident near Lafayette, Louisiana. 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
a short in the 'jam proof system' solenoid valve which prevented activation of the backup hydraulic system and resulting in a cyclic hardover. Factors were the contaminated hydraulic fluid and the resulting jammed actuator (longitudinal control slider).
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 18, 1995 · about 2:40 pm local time
- Place
- Lafayette, Louisiana · map
- Type
- Incident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Mbb BO-105C
- Registration
- N91070 · no longer on the register · serial S145
- Damage
- Not recorded
- Flight
- Flight of an unrecorded kind · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
While over 'Fast Lane,' a visual check point on the highway approach to the Lafayette Regional Airport, the helicopter 'abruptly and violently pitched nose down.' It took both pilots pulling aft on the cyclic to level the helicopter. Once control was re-established, the PIC saw that the 'hyd block' light was illuminated and the Mast Moment Indicator (MMI) limit light was on steady. The helicopter was landed without further incident. Examination and testing of the Tandem Hydraulic Unit found the System 1 hydraulic pump leaking internally. A nick and an abrasion were found in the edge of its longitudinal control slider. Metallic chips were found in the hydraulic high and low pressure filters, and one chip was found in a groove of the longitudinal control slider. The electrical portion of the 'jam-proof system,' which should activate the back-up hydraulic system two in case of a control slider jamming, only worked randomly. The connector was heavily corroded and the magnetic core of the solenoid valve had an internal short circuit.
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: flight instructor, commercial pilot
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 7,761 hours in all; 4,004 in this make and model
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 8,285 hours
- Last inspection: approved inspection programme, August 14, 1995; 33 hours since
- Maximum gross weight: 4,629 lb
- Seats: 6
- Landing gear: fixed
- Engine: Allison 250-C20 (turboshaft); 0 hours total
The flight
- Departed from: LFT at 12:30 pm
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: scat
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
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.