Sail Plane
Flight Crew Commercial; Flight Crew Flight Instructor
Flight Crew Last 90 Days 13; Flight Crew Total 299; Flight Crew Type 104
Situational Awareness; Time Pressure
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Overcame Equipment Problem
Aircraft; Human Factors
Glider used for training flight had been disassembled for polishing and waxing. After assembly; student pilot and instructor rushed preflight inspection to fly ship before sunset and took off without total energy probe installed. Without TE (Total Energy) probe; no instruments (airspeed/altimeter/vertical speed) were operable. Missing probe was not corrected by assembly crew; pilots; instructor who signed off assembly check; or club safety manager at the flight line. Pilots noticed inoperable instruments in flight and landed safely without reference to instruments. Inadequate preflight inspection especially failure to follow written checklist is the most obvious cause. External pressure to fly also was a factor. The club instructing should also teach better ADM (Aeronautical Decision Making) for the go/no-go decision using the PAVE and IMSAFE checklists.
Grob glider instructor reported taking off without the total energy probe installed; so they were without all flight instruments.