AN ACR SAFETY DIRECTOR HAS NOTED THAT THE WORDING OF SNOW NOTAMS REGARDING GS PERFORMANCE IS VERY POOR.

Date: 1994-02 · Aircraft: B727 Undifferentiated or Other Model

Anomalies: other-runway-or-taxiway-excursion

Synopsis

AN ACR SAFETY DIRECTOR HAS NOTED THAT THE WORDING OF SNOW NOTAMS REGARDING GS PERFORMANCE IS VERY POOR.

Narrative

THIS IS ALMOST GOING TO BE AN UNBELIEVABLE STORY; AND I CAN BARELY BELIEVE THAT IT ALL CAME DOWN. THE EWR NOTAM WE READ IS QUOTED DIRECTLY FROM AN FAA ATC ORDER 7930.2E THAT HAS BEEN IN EFFECT FOR YRS AND; WE'RE TOLD; IS THE ONLY NOTAM THAT THE AIRWAYS FACILITIES MAINT FOLKS ARE ALLOWED TO ISSUE AND IS IN EFFECT SYS-SIDE. IT SAYS: ...DUE TO EFFECTS OF SNOW ON GS(;) MINIMUMS TEMPORARILY RAISED TO LOC ONLY CATEGORY C AND D ACFT. GS REMAINS IN SVC; HOWEVER; ANGLE MAY BE DIFFERENT THAN PUBLISHED. THIS MESSAGE WOULD BE GREATLY IMPROVED IF THEY WOULD MERELY ADD THE COMMA THAT I HAVE INDICATED BY (;) LIKE THEY USED AROUND HOWEVER; LATER IN THE MESSAGE. I HAVE TALKED TO EVERYBODY FROM THE ATA TO ATC TO REGION FLT STANDARDS; TO THE MAINTAINERS; ET AL. THERE'S NOTHING WRONG WITH ANYTHING OF THAT ILS; AND THE MONITORS WOULD ALARM FOR AN EXCURSION OF THE GS; EXCEPT THAT THE VARYING SNOW DRIFTS HT AND DENSITY MIGHT(!) CAUSE SOME ABERRATIONS OF THE SIGNAL CLOSE TO THE GND BUT OUT BEYOND THE MONITOR DEVICE ANTENNA; SO(!) JUST TO BE SAFE THEY WANT TO RAISE THE ILS MINIMUMS. TO DO THAT; THEY ONLY NEED TO SAY: ...MINIMUMS TEMPORARILY RAISED TO LOC ONLY CATEGORY C AND D ACFT DUE TO EFFECTS OF SNOW ON GS. THE REMAINDER OF THEIR MESSAGE IS TRITE; MISLEADING AND UNNECESSARY. OF COURSE; THE GS REMAINS IN SVC; SINCE IT IS NOT NOTAMED OUT. OF COURSE THE GS ANGLE MAY VARY BELOW MINIMUMS DUE TO THE IRREGULAR REFLECTIVE SURFACE OF THE SNOWBANK; BUT WHO CARES!; SINCE IT ONLY MIGHT OCCUR BELOW THE NEW; CONSERVATIVE MINIMUMS. (THIS IS NOT A NOTICE THAT HAS ANYTHING TO DO WITH OBSTACLE CLRNC AS WE MAY BE ALLOWED TO THINK.) WELL; WHAT DOES ALL THIS MEAN? PROBABLY NOTHING; EXCEPT THAT THE REGION FLT STANDARDS GUY UNDERSTANDS WHAT WE ARE SAYING AND PROMISES TO RUN IT UP THE FLAGPOLE. GOOD LUCK; AND WITH THAT WE CLOSE THIS WITH THE THOUGHT THAT THE ONLY WAY WE MIGHT INFLUENCE THIS CHANGE IS VIA THE NASA ASRS RPT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR IS THE SAFETY DIRECTOR FOR A UNITED STATES BASED AIR FREIGHT ACR. HE IS A RETIRED USAF AIR TFC CTLR. HE WAS WITH THE USAF SAFETY DIRECTORATE WHEN IT HELPED TO SET UP THE ASRS BACK IN THE OLD DAYS. HIS ACR HAS A SYS SIMILAR TO THE ASRS FOR INTERNAL RPTING INCIDENTS BY ITS PERSONNEL. THE RPTR WOULD LIKE TO SEE THE WORDING OF THE STANDARD SNOW NOTAM CHANGED SO THAT IT WOULD NOT LEAD PLTS TO THINK THAT THE GS IS OTS. HE HAS CALLED MANY PEOPLE IN THE FAA HAD BEEN TOLD THAT THIS IS THE WAY THAT IT IS. THE RPTR AND THIS ANALYST WOULD ALSO LIKE TO SEE THE FAA MAKE A COMPLETE SENTENCE TO READ 'DUE TO THE AFFECTS OF SNOW ON THE GS; ILS MINIMUMS ARE TEMPORARILY RAISED TO LOC ONLY MINIMUMS FOR CATEGORY C AND D ACFT. THE GS REMAINS IN SVC. HOWEVER; THE ANGLE MAY BE DIFFERENT FROM PUBLISHED.'

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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.