Narrative:

I was acting as flight instructor in the rear seat of the glider (scheibe sf-34) with the student pilot flying the aircraft from the front seat. Runway 26 was in use for takeoff and landing. Surface wind was from the south at about 5-10 KTS. The landing incident occurred on the last of 4 patterns and lndgs. The student flew a normal pattern to roll out on the extended runway centerline and then used a mild slip with the left wing low to correct for the left crosswind. The student planned for a touchdown just beyond the 1000 ft runway marker and on the right half (downwind side) of the runway. His descent rate was within normal range and the longitudinal axis of the glider was aligned with its track along the runway. At touchdown; the attachment bolts for the landing gear shock struts failed and the landing gear collapsed into the gear well. I took control of the glider and it slid to a gradual stop on the right side of the runway near the intersection of taxiway D. No one was injured during the incident. Because of turbulence or a slightly incomplete flare; touchdown was firm but no harder than I have experienced with other students who are learning to land the glider. Prior to touchdown; a safe landing was never seriously in doubt and I did not feel it necessary to assist on the controls. I do not feel that the touchdown was firm enough that it should have caused any damage. Landing gear failure at the shock strut attachment points has occurred previously in this glider and may indicate a need for more frequent inspections or a change in the components.

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Original NASA ASRS Text

Title: SCHEIBE SF34 GLIDER PLT HAS THE LNDG GEAR COLLAPSE DURING LNDG.

Narrative: I WAS ACTING AS FLT INSTRUCTOR IN THE REAR SEAT OF THE GLIDER (SCHEIBE SF-34) WITH THE STUDENT PLT FLYING THE ACFT FROM THE FRONT SEAT. RWY 26 WAS IN USE FOR TKOF AND LNDG. SURFACE WIND WAS FROM THE S AT ABOUT 5-10 KTS. THE LNDG INCIDENT OCCURRED ON THE LAST OF 4 PATTERNS AND LNDGS. THE STUDENT FLEW A NORMAL PATTERN TO ROLL OUT ON THE EXTENDED RWY CTRLINE AND THEN USED A MILD SLIP WITH THE L WING LOW TO CORRECT FOR THE L XWIND. THE STUDENT PLANNED FOR A TOUCHDOWN JUST BEYOND THE 1000 FT RWY MARKER AND ON THE R HALF (DOWNWIND SIDE) OF THE RWY. HIS DSCNT RATE WAS WITHIN NORMAL RANGE AND THE LONGITUDINAL AXIS OF THE GLIDER WAS ALIGNED WITH ITS TRACK ALONG THE RWY. AT TOUCHDOWN; THE ATTACHMENT BOLTS FOR THE LNDG GEAR SHOCK STRUTS FAILED AND THE LNDG GEAR COLLAPSED INTO THE GEAR WELL. I TOOK CTL OF THE GLIDER AND IT SLID TO A GRADUAL STOP ON THE R SIDE OF THE RWY NEAR THE INTXN OF TXWY D. NO ONE WAS INJURED DURING THE INCIDENT. BECAUSE OF TURB OR A SLIGHTLY INCOMPLETE FLARE; TOUCHDOWN WAS FIRM BUT NO HARDER THAN I HAVE EXPERIENCED WITH OTHER STUDENTS WHO ARE LEARNING TO LAND THE GLIDER. PRIOR TO TOUCHDOWN; A SAFE LNDG WAS NEVER SERIOUSLY IN DOUBT AND I DID NOT FEEL IT NECESSARY TO ASSIST ON THE CTLS. I DO NOT FEEL THAT THE TOUCHDOWN WAS FIRM ENOUGH THAT IT SHOULD HAVE CAUSED ANY DAMAGE. LNDG GEAR FAILURE AT THE SHOCK STRUT ATTACHMENT POINTS HAS OCCURRED PREVIOUSLY IN THIS GLIDER AND MAY INDICATE A NEED FOR MORE FREQUENT INSPECTIONS OR A CHANGE IN THE COMPONENTS.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.