What was found
AFTER ENGINE START CREW REPORTED SMOKE IN THE COCKPIT COMING FROM THE CASPER VENTS. FOUND HYDRAULIC RETURN LINE B NUT LEAKING AT PYLON ON NR 1 ENGINE. SECURED AND OPERATED ENGINE WITH NO LEAKS REMOVED AND REPLACED NR 1 PACK COALESCER BAG PER MM 21-51-16-3. OPERATED PACKS USING ENGINE BLEED AIR WITH NO SKYDROL VAPOR. COMPLETED PROCEDURE FOR CLEARING CONTAMINATION FROM A/C PACKS PER AMM 21-50-00-3. CLEANED COALESCER BAGS PER AMM 21-51-16-3. OK FOR SERVICE.