MBB BO-105C N91070

Summary

On 18 September 1995 at about 14:40 local time, a MBB BO-105C registered N91070 was involved in an incident near Lafayette, Louisiana, United States. 2 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

18 September 1995 at 14:40

Classification

Incident

Location

Lafayette, Louisiana, United States

Coordinates

30.1593, -92.0304

Aircraft

MBB BO-105C

Registration

N91070

Category

Helicopter

Engines

2

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Unknown

Phase of flight

Not recorded

Aircraft damage

Not recorded

Weather

VMC

Light

Day

NTSB number

FTW95IA397

Nobody was injured.

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).

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.