B747 CREW HAD PROBS EXTENDING BOTH THE LEADING AND TRAILING EDGE FLAPS.

Narrative

WE INITIALLY HAD A FAILURE OF THE LEADING EDGE FLAPS TO EXTEND NORMALLY. ALTERNATE EXTENSION OF THE LEADING EDGE FLAPS WAS ACCOMPLISHED. THEN ANOTHER PROB BECAME COGNIZANT. THE FLAP HANDLE WAS POSITIONED TO '5 DEGS' FOR THE ALTERNATE LEADING EDGE FLAP EXTENSION PROC. IT WAS INDICATING THE OUTBOARD TRAILING EDGE FLAPS WERE AT 0 DEGS; WHILE THE INBOARD TRAILING EDGE FLAPS WERE INDICATING 5 DEGS. THE FLAP HANDLE CTLS BOTH LEADING EDGE FLAPS AND TRAILING EDGE FLAPS; BUT THEY OPERATE DIFFERENTLY. THE LEADING EDGE FLAPS ARE PNEUMATICALLY OPERATED; THE TRAILING EDGE FLAPS ARE HYDRAULICALLY OPERATED. INBOARD TRAILING EDGE FLAPS HYD SYS #1; OUTBOARD TRAILING EDGE FLAPS HYD SYS #4. INITIALLY ACCOMPLISHED THE SPLIT TRAILING EDGE FLAPS PROC DOWN TO THE POINT OF 'FOR LNDG EXTEND OPERABLE TRAILING EDGE FLAPS TO 25 DEGS ON FLAP SPD SCHEDULE.' AT THIS POINT WE DISCONTINUED WITH THE SPLIT TRAILING EDGE FLAPS PROC AND COMMENCED THE 'ALTERNATE TRAILING EDGE FLAP OPS PROC. THIS SEEMED TO BE INCORRECT TO USE THE PROC DUE TO THE POSSIBILITY OF SYS PROTECTION FEATURES BEING COMPROMISED. THE OUTBOARD TRAILING EDGE WERE EVENTUALLY EXTENDED TO 25 DEGS; THE INBOARD TRAILING EDGE FLAPS WOULD ONLY EXTEND TO APPROX 8 DEGS. REVERTED BACK TO SPLIT TRAILING EDGE FLAP CHKLIST AND COMPLETED THAT IN ITS ENTIRETY. DECLARED AN EMER AND MADE AN UNEVENTFUL LNDG. RECOMMEND FOR FURTHER USE THAT THE ALTERNATE TRAILING EDGE FLAP OP CHKLIST CONTAIN IN BOLD LETTER CAUTION SOMETHING TO THE EFFECT 'IF ASYMMETRICAL/SPLIT TRAILING EDGE FLAP OCCURS DO NOT INITIATE THE ALTERNATE TRAILING EDGE FLAP OP. ACCOMPLISH THE ASYMMETRICAL/SPLIT TRAILING EDGE FLAPS PROC.' SUPPLEMENTAL INFO FROM ACN 473099: ON APCH FOR LNDG; THE LEADING EDGE FLAPS DID NOT EXTEND BY NORMAL MEANS. THE LEADING EDGE FLAPS WERE THEN EXTENDED BY THE ALTERNATE PROC. WHEN THE FLAP HANDLE WAS POSITIONED TO 5 DEGS; IT WAS DISCOVERED THAT THE OUTBOARD TRAILING EDGE FLAPS WERE STILL AT ZERO DEG AND INBOARD TRAILING EDGE FLAPS WERE AT THE CORRECT 5 DEG POS. SINCE THIS WAS A SPLIT FLAP CONDITION; THE ASYMMETRICAL TRAILING EDGE SPLIT FLAP PROC WAS ACCOMPLISHED TO THE STEP WHERE THE CHKLIST STATES 'FOR LNDG; EXTEND OPERABLE TRAILING EDGE FLAPS TO 25 DEGS ON FLAP SCHEDULE.' AT THIS POINT THE ALTERNATE TRAILING EDGE FLAP OP WAS COMPLETED; THE OUTBOARD TRAILING EDGE FLAPS LOWERED TO 25 DEGS AND AN UNEVENTFUL LNDG ACCOMPLISHED. AFTER RPTING THE INCIDENT TO OUR COMPANY WE WERE INFORMED THAT THE CORRECT PROC WOULD HAVE BEEN TO CONTINUE WITH THE ASYMMETRY/SPLIT TRAILING EDGE FLAP CHKLIST AND ATTEMPT TO LOWER THE OPERABLE FLAPS WITH NORMAL HYD PRESSURE. THEN FLY THE APCH AT VREF +25 WITH WHATEVER FLAPS RESULTED FROM THIS PROC. WE USED THE ALTERNATE METHOD BECAUSE OF THE AMBIGUOUS TERMINOLOGY IN THE CHKLIST. THE AFOREMENTIONED STEP IN THE ASYMMETRY/SPLIT TRAILING EDGE FLAPS PROC SHOULD READ 'FOR LNDG; LOWER OPERABLE TRAILING EDGE FLAPS HYDRAULICALLY TO 25 DEGS ON SCHEDULE USING THE FLAP HANDLE. DO NOT USE THE ALTERNATE TRAILING EDGE FLAP OP.' THIS REVISION TO THE AOM AND QRH SHOULD PREVENT ANY FUTURE CONFUSION IN THE EVENT OF ASYMMETRY/SPLIT TRAILING EDGE FLAPS SIT.