Narrative:

We were cleared to 14000 ft and reset the altimeters passing FL180. ATC had assigned 250 KTS and maximum rate down. Speed brakes were extended and ATC was told we were at maximum rate for the speed. ATC revised our cleared altitude to 15000 ft. This was set in the altitude alert and verified at 17000 ft. During this period a flight attendant was admitted to the cockpit, we were struck by lightning, entered moderate turbulence, and a very tense ATC environment existed as several aircraft were in the same cell. As we approached 16000 ft, the speed brake was retracted. The autoplt did not level the aircraft at 15000 ft and there was no altitude alert warning. As the first officer's altimeter went through 15000 ft, the first officer disconnected the autoplt and advanced the throttles. The aircraft began climbing with a minimum altitude of 14700 ft. We received a TCASII TA and a call from ATC and the captain said we need to get down to 15000 ft. A quick check of his standby altimeter confirmed agreement with the first officer and 15000 ft was captured manually. It was discovered that the captain's primary altimeter setting had been set to 30.31 instead of 29.31. The turbulence, lightning and ATC workload contributed to the distraction. The flight attendant was unaware of the workload and we did not know he was bringing up a maintenance form. Supplemental information from acn 398961: flight attendant knocked on door due to problem passenger during altimeter setting. Altimeter was 29.31, captain inadvertently set 30.31 on one altimeter and 29.31 on the other. Callback conversation with reporter acn 398960 revealed the following information: the reporter stated that the autoplt on the B757 and B767 is in concert with the captain's altimeter so that any errors set in that altimeter would affect the altitude that the aircraft would capture during automatic capture operation. The altimeter was showing 16000 ft when they were actually at 15000 ft so it was not in a 'capture' mode yet. The altitude alert chime also works off the captain's altimeter so the crew did not get that warning. The airline normally has the cabin attendant bring up the cabin maintenance log for review and signature. The flight attendant came in at the wrong time, just as they hit the turbulence and lightning.

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Original NASA ASRS Text

Title: A B757 FLC FAILS TO LEVEL OFF AT 15000 FT WHILE IN DSCNT. SOME CONFUSION DURING INCLEMENT WX IN SETTING THE CAPT'S ALTIMETER CORRECTLY.

Narrative: WE WERE CLRED TO 14000 FT AND RESET THE ALTIMETERS PASSING FL180. ATC HAD ASSIGNED 250 KTS AND MAX RATE DOWN. SPD BRAKES WERE EXTENDED AND ATC WAS TOLD WE WERE AT MAX RATE FOR THE SPD. ATC REVISED OUR CLRED ALT TO 15000 FT. THIS WAS SET IN THE ALT ALERT AND VERIFIED AT 17000 FT. DURING THIS PERIOD A FLT ATTENDANT WAS ADMITTED TO THE COCKPIT, WE WERE STRUCK BY LIGHTNING, ENTERED MODERATE TURB, AND A VERY TENSE ATC ENVIRONMENT EXISTED AS SEVERAL ACFT WERE IN THE SAME CELL. AS WE APCHED 16000 FT, THE SPD BRAKE WAS RETRACTED. THE AUTOPLT DID NOT LEVEL THE ACFT AT 15000 FT AND THERE WAS NO ALT ALERT WARNING. AS THE FO'S ALTIMETER WENT THROUGH 15000 FT, THE FO DISCONNECTED THE AUTOPLT AND ADVANCED THE THROTTLES. THE ACFT BEGAN CLBING WITH A MINIMUM ALT OF 14700 FT. WE RECEIVED A TCASII TA AND A CALL FROM ATC AND THE CAPT SAID WE NEED TO GET DOWN TO 15000 FT. A QUICK CHK OF HIS STANDBY ALTIMETER CONFIRMED AGREEMENT WITH THE FO AND 15000 FT WAS CAPTURED MANUALLY. IT WAS DISCOVERED THAT THE CAPT'S PRIMARY ALTIMETER SETTING HAD BEEN SET TO 30.31 INSTEAD OF 29.31. THE TURB, LIGHTNING AND ATC WORKLOAD CONTRIBUTED TO THE DISTR. THE FLT ATTENDANT WAS UNAWARE OF THE WORKLOAD AND WE DID NOT KNOW HE WAS BRINGING UP A MAINT FORM. SUPPLEMENTAL INFO FROM ACN 398961: FLT ATTENDANT KNOCKED ON DOOR DUE TO PROB PAX DURING ALTIMETER SETTING. ALTIMETER WAS 29.31, CAPT INADVERTENTLY SET 30.31 ON ONE ALTIMETER AND 29.31 ON THE OTHER. CALLBACK CONVERSATION WITH RPTR ACN 398960 REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT THE AUTOPLT ON THE B757 AND B767 IS IN CONCERT WITH THE CAPT'S ALTIMETER SO THAT ANY ERRORS SET IN THAT ALTIMETER WOULD AFFECT THE ALT THAT THE ACFT WOULD CAPTURE DURING AUTO CAPTURE OP. THE ALTIMETER WAS SHOWING 16000 FT WHEN THEY WERE ACTUALLY AT 15000 FT SO IT WAS NOT IN A 'CAPTURE' MODE YET. THE ALT ALERT CHIME ALSO WORKS OFF THE CAPT'S ALTIMETER SO THE CREW DID NOT GET THAT WARNING. THE AIRLINE NORMALLY HAS THE CABIN ATTENDANT BRING UP THE CABIN MAINT LOG FOR REVIEW AND SIGNATURE. THE FLT ATTENDANT CAME IN AT THE WRONG TIME, JUST AS THEY HIT THE TURB AND LIGHTNING.

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.