Narrative:

Even though satcom said 'available' on VMC; when I tried to call dispatch on it; it quickly failed. This is what it did to me the other night: airborne; north of ZZZZ; circuit breakers were pulled and reset; and this process repeated several times. In each instance; the satcom said 'available' and then failed when actually used. The mechanic came to aircraft and stated; 'captain; this satcom never works at the gate area; but will work in the air; I promise you.' I then asked him if he had ever been in the air and watched tested then outside the ramp area of ZZZZ? He said 'no.' now; I know that he knows (we all know) that there is a documented reception problem (just by me and other capts) in ZZZZ with the satcom. And yet; we still have mechanics coming up to crews with misleading and manipulative statements like this: 'it will work in the air; I guarantee it!' this bothers me far more than the current satcom reception problems. There is now a trust issue here. I then told him I would write up the satcom 'anyway' and not take the aircraft unless I could get a 'clear HF' contact with dispatch. To my amazement; that night we did. However; this is not always the case. One frequency worked good. The other frequencys both higher and lower; did not. Had the HF radio not worked; I would have canceled the flight. Satcom circuit breakers were all pulled and collared and it was deferred. ACARS did not work for most of the flight. HF checks were accomplished hourly en route and all worked on set frequency.

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Original NASA ASRS Text

Title: AN AIR CARRIER PILOT REPORTS THAT SATCOM DOES NOT WORK IN MOST AREAS OF SOUTH AMERICA. AIR CARRIER MAINTENANCE INSISTS SATCOM WORKS IN FLIGHT BUT REPORTER BELIEVES THAT IT WILL NOT.

Narrative: EVEN THOUGH SATCOM SAID 'AVAILABLE' ON VMC; WHEN I TRIED TO CALL DISPATCH ON IT; IT QUICKLY FAILED. THIS IS WHAT IT DID TO ME THE OTHER NIGHT: AIRBORNE; N OF ZZZZ; CIRCUIT BREAKERS WERE PULLED AND RESET; AND THIS PROCESS REPEATED SEVERAL TIMES. IN EACH INSTANCE; THE SATCOM SAID 'AVAILABLE' AND THEN FAILED WHEN ACTUALLY USED. THE MECH CAME TO ACFT AND STATED; 'CAPT; THIS SATCOM NEVER WORKS AT THE GATE AREA; BUT WILL WORK IN THE AIR; I PROMISE YOU.' I THEN ASKED HIM IF HE HAD EVER BEEN IN THE AIR AND WATCHED TESTED THEN OUTSIDE THE RAMP AREA OF ZZZZ? HE SAID 'NO.' NOW; I KNOW THAT HE KNOWS (WE ALL KNOW) THAT THERE IS A DOCUMENTED RECEPTION PROB (JUST BY ME AND OTHER CAPTS) IN ZZZZ WITH THE SATCOM. AND YET; WE STILL HAVE MECHS COMING UP TO CREWS WITH MISLEADING AND MANIPULATIVE STATEMENTS LIKE THIS: 'IT WILL WORK IN THE AIR; I GUARANTEE IT!' THIS BOTHERS ME FAR MORE THAN THE CURRENT SATCOM RECEPTION PROBS. THERE IS NOW A TRUST ISSUE HERE. I THEN TOLD HIM I WOULD WRITE UP THE SATCOM 'ANYWAY' AND NOT TAKE THE ACFT UNLESS I COULD GET A 'CLEAR HF' CONTACT WITH DISPATCH. TO MY AMAZEMENT; THAT NIGHT WE DID. HOWEVER; THIS IS NOT ALWAYS THE CASE. ONE FREQ WORKED GOOD. THE OTHER FREQS BOTH HIGHER AND LOWER; DID NOT. HAD THE HF RADIO NOT WORKED; I WOULD HAVE CANCELED THE FLT. SATCOM CIRCUIT BREAKERS WERE ALL PULLED AND COLLARED AND IT WAS DEFERRED. ACARS DID NOT WORK FOR MOST OF THE FLT. HF CHKS WERE ACCOMPLISHED HRLY ENRTE AND ALL WORKED ON SET FREQ.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.