B747 CREW DID NOT MEET A SID XING RESTR ON DEP AT LLBG.

Narrative

ON MAY/XX/99 ISRAELI ATC RPTED A COMPLAINT OF A NEAR MISS TO MY COMPANY; RPTED BY AN UNKNOWN TYPE GA ACFT DURING OUR DEP FROM THE TEL AVIV; BEN GURION ARPT. CONDITIONS ON DEP WERE VFR WITH HAZE. THE OUTSIDE AIR TEMP WAS 32 DEGS C AND RWY 30; DEENA 1F SPECIAL SID WAS ASSIGNED. AFTER REVIEWING THE PROC AND ACFT PERFORMANCE; WE DEPARTED RWY 30 USING MAX THRUST AND FLAPS 20 DEGS. USING COMPANY PRESCRIBED FLT PROFILES; FLAPS WERE RETRACTED TO FLAPS 10 DEGS AND THAT SETTING PLUS V2 +10 KTS AIRSPD MAINTAINED UNTIL REACHING 3000 FT MSL. AFTER DEP; THE OUTSIDE AIR TEMP INCREASED TO 38 DEGS C IN AN INVERSION AND A SIGNIFICANT REDUCTION IN PWR WAS MADE TO MAINTAIN ENG TEMPS AT THE MAX ALLOWABLE LIMITS. WITH A REDUCTION IN PWR CAME A DEGRADATION IN CLB PERFORMANCE. UPON REACHING 7 DME ON THE 270 DEG RADIAL OF THE BGN VOR; THE SID REQUIRES AN ALT OF 3000 FT MSL. THE ACFT HAD REACHED AN ALT OF 2500 FT MSL. NO TFC WAS SIGHTED BY THE CREW OR ISSUED BY ATC DURING THE SID PROC. AT APPROX 6 DME ON THE BGN VOR 270 DEG RADIAL; A TA WAS ISSUED BY THE TCASII FOR TFC AT 12 O'CLOCK; 1 MI; 500 FT BELOW. DUE TO THE ACFT BEING IN A MAX PERFORMANCE ATTITUDE AND PWR SETTINGS; LITTLE TO NO ADDITIONAL CLB RATE COULD BE ACHIEVED. THE OTHER TFC PASSED 700 FT BELOW ACCORDING TO THE TCASII TA ALERT. A SOLUTION TO AN UNEXPECTED PERFORMANCE LOSS AND ASSOCIATED DEGRADATION OF CLB MIGHT BE A NOTE ON THE SID INDICATING TEMP INVERSIONS ARE COMMON IN THE AREA; IF SUCH IS THE CASE. HOWEVER; IF STRICT ALT ADHERENCE IS REQUIRED; A BETTER SOLUTION MIGHT BE TO AUTOMATICALLY ISSUE A PRIOR LOWER ALT XING RESTR TO HVY ACFT OVER A PREDETERMINED MAX TKOF GROSS WT. THIS WOULD BE SAFER AND BETTER THAN RELYING ON FLC JUDGEMENT TO DEAL WITH EXISTING BUT UNKNOWN WX PHENOMENA.