Schempp-Hirth VENTUS A/16.6 N8KS

Summary

On 31 May 1992 at about 23:00 local time, a Schempp-Hirth VENTUS A/16.6 registered N8KS, operated by ROY S. Cundiff, was involved in an accident near Tucson, Arizona, United States. One person was on board and one was seriously injured. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

31 May 1992 at 23:00

Classification

Accident

Location

Tucson, Arizona, United States

Coordinates

31.9003, -111.3600

Aircraft

Schempp-Hirth VENTUS A/16.6

Registration

N8KS

Category

Glider

Operator

ROY S. Cundiff

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

LAX92LA225

1 person was seriously injured.

THE INFLIGHT DISCONNECTION OF THE RIGHT AILERON 'OTELLIER COUPLER FITTING DUE TO LUBRICANTS ON THE COUPLER SLIDE LOCK PLATE, AND THE FAILURE OF THE GLIDER MANUFACTURER TO INCLUDE APPROPRIATE PRECAUTIONARY INFORMATION IN THE MAINTENANCE AND/OR FLIGHT MANUAL. FACTORS IN THE ACCIDENT WERE: THE FAILURE OF THE GLIDER AND FITTING MANUFACTURERS TO MANDATE FAIL/SAFE DEVICES FOR THE COUPLER FITTING, AND THE DESIGN OF THE GLIDER REGARDING THE FACILITATION OF THE COUPLER CONNECTIONS DURING THE GLIDER ASSEMBLY PROCESS.

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

Read the full NTSB narrative

AFTER 4.2 HOURS OF FLIGHT WHILE CRUISING AT 8,000 FT, THE RIGHT AILERON CONTROL SYSTEM 'OTELLIER FITTING DISCONNECTED. THE PILOT SAID THAT THE AILERON TRAIL POSITION IN THE AIRSTREAM CAUSED THE GLIDER TO ENTER A SPIRAL DIVE TO THE RIGHT WHICH COULD NOT BE STOPPED BY LEFT AILERON OR RUDDER. THE PILOT BAILED OUT ABOUT 1,000 FT AGL. THE GLIDER WAS ASSEMBLED ON 5/30/92 IN ACCORDANCE WITH THE FLT & MAINT MANUAL. THE GLIDER WAS THEN FLOWN FOR 4.6 HRS & PARKED OVERNIGHT. THE PILOT SAID HE LUBED THE MALE BALL FITTING PRIOR TO ASSEMBLY AS INSTRUCTED IN THE MANUAL & CLEANED & LUBED THE SLIDE LOCK PLATE WITH WD-40. THE FITTING MANUFACTURERS SAFETY MAINT INFO (NOT AVAILABLE TO PILOTS) REQUIRES THE BALL & SOCKET FITTINGS TO BE LUBED AT EACH ASSEMLBY, BUT CAUTION AGAINST ALLOWING LUBRICANTS ON THE SLIDE LOCK PLATE BECAUSE THE SLIDE 'MAY LOOSE ITS NONREVERSIBILITY' & CAUSE THE FITTING TO DISCONNECT. THE GLIDER MAINT AND FLT MANUAL DOES NOT CAUTION AGAINST LUBRICANTS ON THE SLIDE LOCK PLATE.

Quoted verbatim from the NTSB record.