Narrative:

While on a flight from the spirit of st louis (sus) to la cross (lse) airport I was given a climb to FL230 by center and I climbed to FL250. The individual in the back seat was a military enlisted man with no flight training. During our climb out the aircraft experienced several flashing displays, including a flashing heads up display (HUD). While this sometimes happens as a result of cycling generators or a power interruption, this particular problem was later diagnosed as a failed combined stores computer (csc) and the aircraft was placed in a 'down' status until the component was repaired. The displays were readable and never permanently lost but I mention this because it added a dimension not typically dealt with on a routine flight. As a result of this csc failure I was unable to change radio frequencys via the normal up front control (ufc) push pad method. Instead I was forced to use a backup method that is only used with a failed ufc. I was able to change frequencys and control the radios. However, this alternate method added yet another dimension not typically seen on a routine flight. We received the clearance to climb to FL230 while in overcast conditions. Shortly after receiving and confirming this clearance we experienced a high-pitched squeal over the ics (intercom system) which made inter-cockpit communication impossible. I could hear radio xmissions at the time but only with the radio volumes at the maximum intensity level and even then they were difficult to understand. It was while troubleshooting this particular problem that I climbed through FL230. Shortly after reaching FL250 and clear of the visible moisture, our headset noise subsided and we received the call from ATC asking us to report our altitude. At this point, because of the cockpit headset noise, I am unsure as to whether this was the first call that ATC made with regard to the deviation. I immediately realized the error and descended back to FL230. We followed up the flight by making a call to ZKC and discussed the matter. I provided my name and address to the controller but having never experienced this before I failed to get his name as a reference. I was told that there were no other aircraft involved and that he was planning on submitting the appropriate paperwork. I believe that the primary factor involved was related to being overloaded in the cockpit during climb out. Flying a single seat jet with intermittently flashing displays, changing frequencys via a non-standard method and trying to troubleshoot and deal with the almost unbearable squeal coming across the headset certainly must have had something to do with my altitude deviation. This, however, is no excuse for climbing through FL230. It is during times like these that I need to fall back on the rule of thumb that we all learn early on in our careers, 'aviate, navigation, and communicate.' my concern in this scenario should have been climb to FL230, level off, and now deal with any problems that may exist in the cockpit.

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Original NASA ASRS Text

Title: AN ALT OVERSHOOT, ALTDEV WHEN A MIL PLT EXPERIENCES MULTIPLE MALFUNCTIONS WITH HIS HUD, FREQ SELECTOR AND INTERCOM WHILE CLBING TO FL230 ON FREQ WITH ZKC, MO.

Narrative: WHILE ON A FLT FROM THE SPIRIT OF ST LOUIS (SUS) TO LA CROSS (LSE) ARPT I WAS GIVEN A CLB TO FL230 BY CTR AND I CLBED TO FL250. THE INDIVIDUAL IN THE BACK SEAT WAS A MIL ENLISTED MAN WITH NO FLT TRAINING. DURING OUR CLBOUT THE ACFT EXPERIENCED SEVERAL FLASHING DISPLAYS, INCLUDING A FLASHING HEADS UP DISPLAY (HUD). WHILE THIS SOMETIMES HAPPENS AS A RESULT OF CYCLING GENERATORS OR A PWR INTERRUPTION, THIS PARTICULAR PROB WAS LATER DIAGNOSED AS A FAILED COMBINED STORES COMPUTER (CSC) AND THE ACFT WAS PLACED IN A 'DOWN' STATUS UNTIL THE COMPONENT WAS REPAIRED. THE DISPLAYS WERE READABLE AND NEVER PERMANENTLY LOST BUT I MENTION THIS BECAUSE IT ADDED A DIMENSION NOT TYPICALLY DEALT WITH ON A ROUTINE FLT. AS A RESULT OF THIS CSC FAILURE I WAS UNABLE TO CHANGE RADIO FREQS VIA THE NORMAL UP FRONT CTL (UFC) PUSH PAD METHOD. INSTEAD I WAS FORCED TO USE A BACKUP METHOD THAT IS ONLY USED WITH A FAILED UFC. I WAS ABLE TO CHANGE FREQS AND CTL THE RADIOS. HOWEVER, THIS ALTERNATE METHOD ADDED YET ANOTHER DIMENSION NOT TYPICALLY SEEN ON A ROUTINE FLT. WE RECEIVED THE CLRNC TO CLB TO FL230 WHILE IN OVCST CONDITIONS. SHORTLY AFTER RECEIVING AND CONFIRMING THIS CLRNC WE EXPERIENCED A HIGH-PITCHED SQUEAL OVER THE ICS (INTERCOM SYS) WHICH MADE INTER-COCKPIT COM IMPOSSIBLE. I COULD HEAR RADIO XMISSIONS AT THE TIME BUT ONLY WITH THE RADIO VOLUMES AT THE MAX INTENSITY LEVEL AND EVEN THEN THEY WERE DIFFICULT TO UNDERSTAND. IT WAS WHILE TROUBLESHOOTING THIS PARTICULAR PROB THAT I CLBED THROUGH FL230. SHORTLY AFTER REACHING FL250 AND CLR OF THE VISIBLE MOISTURE, OUR HEADSET NOISE SUBSIDED AND WE RECEIVED THE CALL FROM ATC ASKING US TO RPT OUR ALT. AT THIS POINT, BECAUSE OF THE COCKPIT HEADSET NOISE, I AM UNSURE AS TO WHETHER THIS WAS THE FIRST CALL THAT ATC MADE WITH REGARD TO THE DEV. I IMMEDIATELY REALIZED THE ERROR AND DSNDED BACK TO FL230. WE FOLLOWED UP THE FLT BY MAKING A CALL TO ZKC AND DISCUSSED THE MATTER. I PROVIDED MY NAME AND ADDRESS TO THE CTLR BUT HAVING NEVER EXPERIENCED THIS BEFORE I FAILED TO GET HIS NAME AS A REF. I WAS TOLD THAT THERE WERE NO OTHER ACFT INVOLVED AND THAT HE WAS PLANNING ON SUBMITTING THE APPROPRIATE PAPERWORK. I BELIEVE THAT THE PRIMARY FACTOR INVOLVED WAS RELATED TO BEING OVERLOADED IN THE COCKPIT DURING CLBOUT. FLYING A SINGLE SEAT JET WITH INTERMITTENTLY FLASHING DISPLAYS, CHANGING FREQS VIA A NON-STANDARD METHOD AND TRYING TO TROUBLESHOOT AND DEAL WITH THE ALMOST UNBEARABLE SQUEAL COMING ACROSS THE HEADSET CERTAINLY MUST HAVE HAD SOMETHING TO DO WITH MY ALTDEV. THIS, HOWEVER, IS NO EXCUSE FOR CLBING THROUGH FL230. IT IS DURING TIMES LIKE THESE THAT I NEED TO FALL BACK ON THE RULE OF THUMB THAT WE ALL LEARN EARLY ON IN OUR CAREERS, 'AVIATE, NAV, AND COMMUNICATE.' MY CONCERN IN THIS SCENARIO SHOULD HAVE BEEN CLB TO FL230, LEVEL OFF, AND NOW DEAL WITH ANY PROBS THAT MAY EXIST IN THE COCKPIT.

Data retrieved from NASA's ASRS site as of July 2007 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.