THE FLC HAD TO CYCLE THE ALT ALERTER THROUGH MANY ALTS BEFORE THE WARNING WOULD SILENCE. THE RPTR RESET THE ALT ALERTER TO WHAT HE THOUGHT WAS HIS ASSIGNED ALT BUT COULD NOT BE SURE.

Narrative

THIS FLT WAS THE FIRST IN A SERIES OF EARLY MORNING DEPS; (SHOW AT XA:00 AM EST). ON CLB OUT FROM DTW; THE FO WAS FLYING. AT APPROX 12000 FT MSL; THE ALT ALERTER BEGAN TO SOUND AURALLY. THIS WAS OBVIOUSLY IN ERROR BECAUSE WE WERE WELL BELOW OUR ASSIGNED ALT. AFTER DIALING THE ALERTER DOWN A FEW THOUSAND FT TO RESET IT; I PLACED IT ON 16000 FT; WHICH I UNDERSTOOD WAS OUR ASSIGNED ALT TO CLB TO. AT 16000 FT; THE FO LEVELED THE ACFT. CTR CTLR ASKED IF WE WERE AT 16000 FT AND I REPLIED 'AFFIRMATIVE; LEVELING 1-6 THOUSAND.' THE CTLR THEN REPLIED; 'OK; MAINTAIN 1-6 THOUSAND; ALTIMETER...' (SETTING NOT RECALLED). IT WAS THIS REMARK THAT LED US TO BELIEVE WE COULD HAVE POSSIBLY BEEN CLRED ONLY TO A LOWER ALT THAN 16000 FT. NEITHER MYSELF OR THE FO COULD RECALL BEING ASSIGNED A DIFFERENT ALT; OR EVEN BEING ASSIGNED 16000 FT; EVEN THOUGH IT IS OUR NORMAL CRUISE ALT AND IT WAS SET IN THE ALT ALERT DEVICE. BECAUSE THE CTLR TOLD US TO MAINTAIN 1-6 THOUSAND; NO CORRECTIVE ACTION WAS NECESSARY. AN INCONSISTENT ALT ALERT DEVICE; LACK OF QUALITY CREW REST; OR SIMPLE PLT ERROR ARE POSSIBLE CAUSES OF THIS INCIDENT; IF IN FACT ANY INCIDENT ACTUALLY OCCURRED. IT IS POSSIBLE THAT 16000 FT WAS OUR ASSIGNED ALT AND NO ERROR WAS MADE.