A C172 TRAINING FLT ENDS WITH A HARD LNDG WHICH DAMAGES THE ACFT AT TKI; TX.

Narrative

I WAS PRACTICING LNDGS WITH A STUDENT AT MCKINNEY ARPT; RWY 17. WE HAD A GOOD 1.5 HRS OF TRAINING AND I DECIDED TO TAKE MY STUDENT BACK IN THE PATTERN. HE HAD BEEN HAVING VARIOUS PROBS WITH THE LNDG PHASE; INCLUDING PITCH ATTITUDE AND THE FLARE. HE HAD BEEN DOING WELL WITH HIS PITCH IN THE PREVIOUS ATTEMPTS; AND I HAD FELT IT WAS TIME TO MOVE ON TO THE FLARES. WE HAD GOTTEN PAST THE POINT IN THIS PART OF THE LNDG WHERE I WAS HELPING HIM WITH THE YOKE AND I WAS TALKING HIM THROUGH IT. ON OUR THIRD LNDG; MY STUDENT DEVELOPED A HIGH GLIDE PATH ON FINAL; AND I INSTRUCTED HIM THAT IN ORDER TO MAINTAIN AIRSPD HE WOULD HAVE TO LOWER THE NOSE MORE IN ORDER TO KEEP FROM STALLING. OVER THE THRESHOLD; HE PITCHED FORWARD VERY EXCESSIVELY AND PROGRESSIVELY DOWN THROUGH GND EFFECT. I PUT BACK PRESSURE IN TO PREVENT A 'WHEELBARROW' LNDG. BECAUSE OF THE EXCESSIVE AIRSPD AND AMOUNT OF BACK PRESSURE; THE PLANE BOUNCED BACK UP ABOVE THE RWY ABOUT HALF OF A WINGSPAN. WE DID HAVE SUFFICIENT AIRSPD TO ATTEMPT ANOTHER FLARE; SO I GUIDED HIM THROUGH ANOTHER; TALKING HIM THROUGH IT. MY STUDENT ABRUPTLY PUT THE PLANE IN ABOUT A 10 DEG PITCH; BRINGING US BEHIND THE PWR CURVE CAUSING IT TO SINK RAPIDLY. AS WE SANK THROUGH GND EFFECT HE BROUGHT THE NOSE UP EVEN FURTHER; INCREASING OUR DSCNT. I REPEATEDLY CALLED FOR PWR AND 'FULL PWR' AS WE DID SO; THE STUDENT DID NOT RESPOND. I THEN CALLED 'MY PLANE' AND WAS ABLE TO APPLY FULL PWR JUST AS THE ACFT HIT THE GND. THE PLANE'S WINDSHIELD COLLAPSED ON US (THERE WAS A CRACK THAT WAS SUBSTANTIAL THAT WE FOUND IN THE WINDSHIELD) AND THE R MAIN GEAR SUFFERED DAMAGE FROM THE IMPACT ON THE GND. CONTRIBUTING FACTORS/JUDGEMENTS/DECISIONS/OTHER FACTORS: THE STUDENT WAS 65 YRS OLD AND HAD DELAYED REACTION TIME; THE STUDENT DID NOT PASS HIS EYESIGHT PORTION OF HIS MEDICAL; THE DAY AFTER (PITCH AND FLARE ATTITUDES); THE EFFECTIVE USE OF FULL PWR; INSTEAD OF 'GAR'; REACTION TIME BY THE INSTRUCTOR IN TAKING PLANE -- INSTRUCTOR PUTTING TOO MUCH FAITH IN STUDENT. SHOULD A MEDICAL BE REQUIRED BEFORE STARTING FLT TRAINING? IN CONCLUSION I BELIEVE THAT RISKS ARE INCLUDED IN TEACHING ANYONE TO FLY AND LAND. BY ASSUMING A TRAINING LEVEL BY JUST EVALUATING PREVIOUS LESSONS AND TRIALS; YOU CAN NEVER BE TOO RIGHT ON THE PERCEPTIONS OF A STUDENT. CORRECTIVE ACTIONS WERE TAKEN AS FAR AS MY STANDARDIZATION. I RECEIVED RECURRENT TRAINING ON ABORTING LNDGS AND GOING AROUND; WHICH WAS NO PROB. MY STUDENT AND I HAVE DISCUSSED AND TRAINED EXCLUSIVELY NOW ON GO AROUND DECISIONS AND LNDG CHARACTERISTICS.