PLT OF CZECH AERO L39 MIL TRAINING JET HAS PRESSURIZATION LOSS WHEN CANOPY SEAL FAILS. HE DOES NOT DECLARE AN EMER BUT MAKES EMER DSCNT WHILE IN CONTACT WITH CTR.

Narrative

THIS ACFT IS IN THE EXPERIMENTAL/EXHIBITION CATEGORY AS A SINGLE ENG TANDEM SEATED TRAINER; BUILT IN THE CZECH REPUBLIC. THIS IS AN EXTREMELY RELIABLE ACFT AND OVER 3000 HAVE BEEN BUILT AND MANY ARE STILL FLYING. THIS ACFT HAD JUST COME OUT OF A MAJOR INSPECTION AND I WAS FERRYING THE ACFT TO THE PAINT FACILITY. PRESSURIZATION IS PROVIDED IN THIS ACFT BY VIRTUE OF AN AIR CYCLE MACHINE AND THE CANOPIES ARE SEALED WITH A RUBBER SEAL USING NITROGEN TO INFLATE THE SEAL. THE SVC CEILING ON THIS ACFT IS 36000 FT; HOWEVER I CHOSE TO REMAIN IN THE LOW 20'S JUST TO BE SURE. RANGE WAS NOT A FACTOR BECAUSE I HAD PUT ON ENOUGH FUEL TO PROVIDE A 50 MIN FUEL RESERVE AT THE LOWER ALT. ABOUT 100 MI OUT FROM LONGVIEW AND LEVEL AT 23000 FT WITH THE AUTOPLT ENGAGED; THE MASTER CAUTION ILLUMINATED INDICATING THE CABIN PRESSURE HAD RISEN BEYOND THE 10000 FT LIMIT. I IMMEDIATELY CONTACTED ZFW; INFORMED THEM I HAD A PRESSURIZATION FAILURE AND I WAS DSNDING FOR A LOWER ALT IMMEDIATELY. I DISENGAGED THE AUTOPLT AND TRIMMED THE ACFT FOR A DSCNT. I LOCATED MY OXYGEN MASK AND TOOK SEVERAL DEEP BREATHS AND THEN LEANED FORWARD IN MY HARNESS TO CHK AND SEE IF IN FACT THE CANOPY SEAL HAD FAILED. MY SUSPICIONS WERE CONFIRMED AS THE COCKPIT BECAME VERY NOISY AND COLD. MEANWHILE; ZFW WERE BEING LESS THAN HELPFUL WHILE CONTINUOUSLY CALLING OUT TFC RATHER THAN GIVING ME SOME SORT OF NEW HEADING SO THAT I COULD GET DOWN BELOW 14000 FT. I WAS FINALLY HANDED OFF TO THE NEXT CTR CTLR FOR LOWER AND WAS CLRED TO DSND TO 11000 FT FOR THE REMAINDER OF THE TRIP. CTR ASKED IF MY SIT WAS UNDER CTL AND I CONFIRMED THAT WITH THIS LOWER ALT; MY SIT WAS NO LONGER DANGEROUS. I DID NOT DECLARE AN EMER PRIOR TO MY DSCNT AND IN RETROSPECT STILL WOULDN'T HAVE DECLARED AN EMER; JUST FOR AN EMER DSCNT. IT WAS; HOWEVER; IN MY OPINION; IMPERATIVE TO GET DOWN TO A BREATHABLE ALT BEFORE MY SENSES WERE IMPAIRED. I DID NOT WAIT FOR THE CTLR TO CLR ME FOR A LOWER ALT PRIOR TO MY DSCNT. I MADE MY DECISION FOR IMMEDIATE DSCNT; AS I HAVE BEEN TRAINED IN THE CPR JETS; (LEAR; CITATION; DIAMOND JET) THAT I HOLD TYPE RATINGS IN AND CURRENTLY FLY. IF I WERE AT A LOWER ALT AND CTR WOULD ASK ME TO TURN TO HELP OUT AND AVOID AN ACFT ON AN EMER DSCNT; I WOULD COMPLY IMMEDIATELY AND WITHOUT ANY CONCERN FOR MY INCONVENIENCE; CONCERNED ONLY WITH THE FELLOW AIRMAN DEALING WITH AN INFLT PROB. THE FLT TERMINATED AT LONGVIEW; TX; WITHOUT FURTHER INCIDENT AND THE CANOPY SEALING SYS UNDER REPAIR.