ALTDEV.

Narrative

I WAS TUNING NAV RADIOS; FO WAS FLYING AT 11000 FT. HE THOUGHT HE HEARD A NEW ALT CLRNC TO A LOWER ALT AND STARTED A SLOW DSCNT. I NOTICED THE ALT CHANGE; AS DID SO; AT 200 FT LOW AND STARTED TO ADVISE FO OF THE DSCNT. A RECOVERY WAS STARTED BACK TO 11000 FT. APPROX 400 FT OF ALT LOSS WAS MAX DEV. ATC CTLR CALLED AT 10600 FT AS WE WERE RECOVERING BACK TO 11000 FT. REST OF FLT WAS NORMAL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR FLIES THE L-1011 ON INTL RTES. HE HAD NEVER BEFORE FLOWN WITH THE FO OF THIS INCIDENT. THIS 6 DAY TRIP INCLUDED 4 XINGS OF THE ATLANTIC. THE FO IS A CAPT THAT HAD TO DOWNGRADE BUT IS NOW UPGRADING AGAIN TO THE B-727. AS THE FO WORE 4 STRIPES; THE RPTR DIDN'T WATCH THE FO AS CLOSELY AS HE MIGHT HAVE. THE SO WARNED THE CAPT THAT 'SOME GUYS DON'T LIKE TO FLY WITH THE FO' AS 'HIS MIND IS NOT ALWAYS THERE.' THE FO IS FINISHING UP HIS THIRD DIVORCE. THE FO 'MAY BE THE TYPE THAT HAS TO TALK TO HIS CHIEF PLT NOW AND AGAIN.' IT IS 'IN FO'S NATURE TO BE A LITTLE HELTER SKELTER.' THE FO FAILED TO CHK WITH THE OTHER CREWMEN BEFORE HE LEFT HIS ALT. THE ALT ALERTER SOUNDED OFF PROPERLY. THE CAPT COULD HAVE PREVENTED THIS BY WATCHING THE FO MORE CLOSELY AND CONTINUOUSLY.