AN ACR FLC CLBED THROUGH THEIR ASSIGNED ALT WHILE PERFORMING A NOISE ABATEMENT DEP.

Narrative

ACFT WAS INITIALLY CLRED FOR TKOF; AND TO CLB AND MAINTAIN 5000 FT. CREW WAS EXTREMELY BUSY PERFORMING THE VERY DIFFICULT AND IN MY OPINION DANGEROUS SPECIAL PROC FROM THE ORANGE COUNTY ARPT. IT REQUIRES EXTENSIVE NONSTANDARD VERT AND LATERAL MANEUVERS IN ORDER TO COMPLY WITH LCL NOISE ABATEMENT POLICY. AFTER COMPLETING MOST OF THESE MANEUVERS; I (COPLT) NOTICED THE CAPT WAS CLBING THROUGH 7500 FT. I LOOKED AT THE ALT WINDOW ON THE MCP AND DISCOVERED IT WAS NOW SET TO READ 10000 FT. AFTER QUESTIONING THE CAPT IF WE HAD BEEN CLRED TO THE HIGHER ALT; HE SAID NO; NOT AS FAR AS HE KNEW. HE QUICKLY LEVELED THE ACFT OFF AT APPROX 7500 FT; AND I CALLED THE TWR (OR DEP CTL) AND ASKED THEM IF WE WERE CLRED TO 10000 FT. HE RESPONDED BY SAYING; 'YOU ARE CLRED TO 10000 FT.' THERE WAS NO CONFLICT WITH ANY OTHER ACFT IN THE AREA; BUT THIS MATTER WAS STILL VERY UNSETTLING TO BOTH OF US. AFTER MUCH DISCUSSION LATER; WE BELIEVE WE HAVE DISCOVERED THE CULPRIT. AFTER AIRSPD AND ALT HAVE BEEN SET INITIALLY ON THE FORWARD PANEL (MCP); ANY TYPE OF PWR (ELECTRICAL) INTERRUPTION WILL CAUSE BOTH THESE 'WINDOWS' TO DEFAULT TO 100 KTS AND 10000 FT. WE HAD SUCH AN INTERRUPTION SHORTLY BEFORE PUSHBACK FROM THE GATE. WHEN SWITCHING FROM EXTERNAL PWR TO OUR OWN APU PWR; THE CAPT ACCIDENTALLY DISCONNECTED EXTERNAL PWR FROM THE ACFT BEFORE THE APU WAS UP AND RUNNING AND READY TO TAKE OVER THE JOB OF PWRING THE ACFT SYS. WHEN THIS HAPPENED THE ACFT WAS TOTALLY UNPWRED (EXCEPT FOR BATTERY) FOR A FEW SECONDS. HE QUICKLY RESELECTED EXTERNAL PWR; AND ALL ELECTRICAL SYS WERE AGAIN PWRED. WHAT WE DID NOT REALIZE IS THAT THE AIRSPD AND ALT 'WINDOWS' HAD DEFAULTED TO 100 KTS AND 10000 FT. THE AIRSPD MISTAKE WAS CAUGHT ON TAXI OUT (VIA CHKLIST); BUT THE ALT APPARENTLY WAS NOT. IF WE BOTH HAD NOT BEEN SO EXTREMELY OCCUPIED WITH PERFORMING THIS RIDICULOUS SPECIAL TKOF PROC; I'M CERTAIN WE BOTH WOULD HAVE CAUGHT IT!