|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Altitude||msl single value : 35000|
|Operator||common carrier : air carrier|
|Make Model Name||B757-200|
|Operating Under FAR Part||Part 121|
|Flight Phase||descent : approach|
|Affiliation||company : air carrier|
|Function||flight crew : first officer|
|Qualification||pilot : atp|
pilot : commercial
pilot : flight engineer
pilot : multi engine
|Experience||flight time last 90 days : 70|
flight time total : 4430
flight time type : 1270
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Anomaly||other anomaly other|
|Independent Detector||other flight crewa|
|Resolutory Action||none taken : anomaly accepted|
Four adverse items continually occur during operations into clark, philippines. 1) weak ATIS. ATIS at clark is transmitted on the VOR frequency (113.1). The transmission seems to be weaker than all other ATIS broadcasts in southeast asia. As a result, pilots are spending inordinate amounts of time trying to decipher the ATIS close in to the field. Additionally, the tower controller indicated that during periods of bad WX, xmissions are even weaker. 2) garbled ATIS. Clark's ATIS computer generated voice is extremely slow speaking, and it is difficult to understand numbers and other phrases, particularly when the aircraft is beyond 50 NM from the field. Even at the field, certain phrases are impossible to understand. 3) sporadic ACARS WX information from clark. After approximately midnight, clark local time, timely and accurate taf's and metar's from clark are almost nonexistent. Generally, within about 30 mins of landing, ACARS WX information comes back up. 4) tower frequency has a low frequency buzz in the background of controller xmissions, sometimes garbling reception. The combination of these above items makes for a possible hazardous approach into clark. For example, on sep/thu/03, we were unable to receive ACARS WX data going into clark. Approximately 30 mins out, we got ACARS data indicating that visibility at crk was 4000 meters. ATIS was garbled, but seemed to parallel what we were seeing on ACARS. While shooting the approach the WX looked 'suspect,' and approach/tower was queried. Tower indicated that his visibility was 100 meters, and RVR was 1000 meters. Minimums for the approach were .8 KM, so the approach was continued, and we broke out right at minimums. Another flight prior to us had difficulty understanding the tower when requesting the WX. It may be possible to help communications at clark, philippines by: 1) change ATIS voice software at clark. A more understandable voice will help pilots to understand ATIS information, even if the transmission is weak. 2) determine why ACARS WX at clark stops being transmitted after midnight. 3) eliminate crk tower transmitter buzz.
Original NASA ASRS Text
Title: A B757 FLT CREW EXPRESSES THEIR CONCERN ABOUT ATIS AND ACARS RECEPTION AT CRK.
Narrative: FOUR ADVERSE ITEMS CONTINUALLY OCCUR DURING OPS INTO CLARK, PHILIPPINES. 1) WEAK ATIS. ATIS AT CLARK IS XMITTED ON THE VOR FREQ (113.1). THE XMISSION SEEMS TO BE WEAKER THAN ALL OTHER ATIS BROADCASTS IN SE ASIA. AS A RESULT, PLTS ARE SPENDING INORDINATE AMOUNTS OF TIME TRYING TO DECIPHER THE ATIS CLOSE IN TO THE FIELD. ADDITIONALLY, THE TWR CTLR INDICATED THAT DURING PERIODS OF BAD WX, XMISSIONS ARE EVEN WEAKER. 2) GARBLED ATIS. CLARK'S ATIS COMPUTER GENERATED VOICE IS EXTREMELY SLOW SPEAKING, AND IT IS DIFFICULT TO UNDERSTAND NUMBERS AND OTHER PHRASES, PARTICULARLY WHEN THE ACFT IS BEYOND 50 NM FROM THE FIELD. EVEN AT THE FIELD, CERTAIN PHRASES ARE IMPOSSIBLE TO UNDERSTAND. 3) SPORADIC ACARS WX INFO FROM CLARK. AFTER APPROX MIDNIGHT, CLARK LCL TIME, TIMELY AND ACCURATE TAF'S AND METAR'S FROM CLARK ARE ALMOST NONEXISTENT. GENERALLY, WITHIN ABOUT 30 MINS OF LNDG, ACARS WX INFO COMES BACK UP. 4) TWR FREQ HAS A LOW FREQ BUZZ IN THE BACKGROUND OF CTLR XMISSIONS, SOMETIMES GARBLING RECEPTION. THE COMBINATION OF THESE ABOVE ITEMS MAKES FOR A POSSIBLE HAZARDOUS APCH INTO CLARK. FOR EXAMPLE, ON SEP/THU/03, WE WERE UNABLE TO RECEIVE ACARS WX DATA GOING INTO CLARK. APPROX 30 MINS OUT, WE GOT ACARS DATA INDICATING THAT VISIBILITY AT CRK WAS 4000 METERS. ATIS WAS GARBLED, BUT SEEMED TO PARALLEL WHAT WE WERE SEEING ON ACARS. WHILE SHOOTING THE APCH THE WX LOOKED 'SUSPECT,' AND APCH/TWR WAS QUERIED. TWR INDICATED THAT HIS VISIBILITY WAS 100 METERS, AND RVR WAS 1000 METERS. MINIMUMS FOR THE APCH WERE .8 KM, SO THE APCH WAS CONTINUED, AND WE BROKE OUT RIGHT AT MINIMUMS. ANOTHER FLT PRIOR TO US HAD DIFFICULTY UNDERSTANDING THE TWR WHEN REQUESTING THE WX. IT MAY BE POSSIBLE TO HELP COMS AT CLARK, PHILIPPINES BY: 1) CHANGE ATIS VOICE SOFTWARE AT CLARK. A MORE UNDERSTANDABLE VOICE WILL HELP PLTS TO UNDERSTAND ATIS INFO, EVEN IF THE XMISSION IS WEAK. 2) DETERMINE WHY ACARS WX AT CLARK STOPS BEING XMITTED AFTER MIDNIGHT. 3) ELIMINATE CRK TWR XMITTER BUZZ.
Data retrieved from NASA's ASRS site as of July 2007 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.