ALTDEV ON INITIAL CLB AFTER LONG AND TEDIOUS WX DELAY.

Narrative

A RESERVE CREW WAS ASSIGNED TO A CONTINUOUS DUTY TRIP SEQUENCE. THE CREW HAD 5 HRS OF REST (BEHIND THE DOOR). THE FLT OUTBOUND WAS SCHEDULED TO DEPART AT APPROX XA00. AT DEP TIME THE WX WAS '0' OBSCURED AND '0' VISIBILITY (RVR OF 1600 FT OR 1/4 MI VISIBILITY WERE THE LEGAL REQUIREMENTS). TAXI CLRNC WAS OBTAINED OVER 1 HR LATE WITH OUR RVR RPTED OF 4000 FT. WAITING FOR TKOF CLRNC THE RVR DROPPED TO 700 FT AND REMAINED THERE FOR THE NEXT 90 MINS. WHEN THE VISIBILITY CAME UP TO MINIMUMS; CLRNC FOR TKOF WAS RECEIVED. UPON ROTATION; THE ANXIOUS PAX RESPONDED WITH LOUD HOOTS AND A ROUND OF APPLAUSE. THIS CAUSED A MOMENTARY DISTR TO THE PIC. AT 400 FT AGL; THE PIC COMMENCED WITH A 40 DEG TURN TO THE L. DURING THE TURN THE PIC NOTICED ABOUT A 75-100 FT DROP IN ALT AND IMMEDIATELY APPLIED CORRECTIVE ACTION. THE FO LATER RPTED A 350 FT DROP IN ALT IN A 3 SECOND TIME FRAME. THE FO NEGLECTED TO MAKE ANY MANDATORY CALLOUTS; ALERTING THE PIC OF ANY ALTDEVS. CONTRIBUTING FACTORS: LACK OF SLEEP COUPLED WITH A LONG DELAY AND LACK OF FOOD. MOMENTARY DISTR WITH NOISE IN BACK. NO CREW COORD; NO CALLOUTS FROM THE PNF.