Narrative:

We were initially cleared J87 for pgs lynds 1 arrival into las. On a subsequent frequency, we were cleared direct drk, direct pgs, then lynsy 1 arrival. We were then reclred the lynds 1 arrival, pgs transition. After drk, we were turned towards pgs instead of following the drk transition. There was some confusion as to whether we were to follow the drk 7 pgs transition. Well, apparently we were on the wrong transition as the controller gave us a 'turn 15 degrees left of heading,' and then eventually back on the transition. I believe these LNAV arrs, in particular, are an accident waiting to happen, because of several reasons. First of all, the company has provided us with no training on how to utilize the LNAV for departure/arrs. The confusion on exactly how to fly them is troublesome. Also, I understand that the FAA has provided very little or insignificant training to the ATC folks. Second, there is not standardization in the procedures, particularly in regards to the verbal phraseology. One day a certain phase might mean one thing to one controller, and have a different meaning to another. Again, sounds like a training/standardization issue to the ATC folks. Third, there are many 'gotchas' in the arrs. In particular are the altitudes at various waypoints. Between the hard altitudes, the soft altitudes, at or above, at or below, the 'descend via' clearance, there is much confusion on both the pilot's part and the ATC controller's part on exactly when the aircraft is legal to descend or not. Overall, I would say 2 things could significantly improve the safety of LNAV in las. First, there needs to be better training for pilots and ATC folks in how to utilize LNAV. Second, there needs to be much better standardization, particularly phraseology, so everybody is on the same page.

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Original NASA ASRS Text

Title: LAS VEGAS ARRS FOUND CONFUSING AND DIFFICULT TO USE BY B737 PLT WHO PERCEIVES THAT ATC IS ALSO HAVING DIFFICULTY USING THEM EFFECTIVELY.

Narrative: WE WERE INITIALLY CLRED J87 FOR PGS LYNDS 1 ARR INTO LAS. ON A SUBSEQUENT FREQ, WE WERE CLRED DIRECT DRK, DIRECT PGS, THEN LYNSY 1 ARR. WE WERE THEN RECLRED THE LYNDS 1 ARR, PGS TRANSITION. AFTER DRK, WE WERE TURNED TOWARDS PGS INSTEAD OF FOLLOWING THE DRK TRANSITION. THERE WAS SOME CONFUSION AS TO WHETHER WE WERE TO FOLLOW THE DRK 7 PGS TRANSITION. WELL, APPARENTLY WE WERE ON THE WRONG TRANSITION AS THE CTLR GAVE US A 'TURN 15 DEGS L OF HDG,' AND THEN EVENTUALLY BACK ON THE TRANSITION. I BELIEVE THESE LNAV ARRS, IN PARTICULAR, ARE AN ACCIDENT WAITING TO HAPPEN, BECAUSE OF SEVERAL REASONS. FIRST OF ALL, THE COMPANY HAS PROVIDED US WITH NO TRAINING ON HOW TO UTILIZE THE LNAV FOR DEP/ARRS. THE CONFUSION ON EXACTLY HOW TO FLY THEM IS TROUBLESOME. ALSO, I UNDERSTAND THAT THE FAA HAS PROVIDED VERY LITTLE OR INSIGNIFICANT TRAINING TO THE ATC FOLKS. SECOND, THERE IS NOT STANDARDIZATION IN THE PROCS, PARTICULARLY IN REGARDS TO THE VERBAL PHRASEOLOGY. ONE DAY A CERTAIN PHASE MIGHT MEAN ONE THING TO ONE CTLR, AND HAVE A DIFFERENT MEANING TO ANOTHER. AGAIN, SOUNDS LIKE A TRAINING/STANDARDIZATION ISSUE TO THE ATC FOLKS. THIRD, THERE ARE MANY 'GOTCHAS' IN THE ARRS. IN PARTICULAR ARE THE ALTS AT VARIOUS WAYPOINTS. BTWN THE HARD ALTS, THE SOFT ALTS, AT OR ABOVE, AT OR BELOW, THE 'DSND VIA' CLRNC, THERE IS MUCH CONFUSION ON BOTH THE PLT'S PART AND THE ATC CTLR'S PART ON EXACTLY WHEN THE ACFT IS LEGAL TO DSND OR NOT. OVERALL, I WOULD SAY 2 THINGS COULD SIGNIFICANTLY IMPROVE THE SAFETY OF LNAV IN LAS. FIRST, THERE NEEDS TO BE BETTER TRAINING FOR PLTS AND ATC FOLKS IN HOW TO UTILIZE LNAV. SECOND, THERE NEEDS TO BE MUCH BETTER STANDARDIZATION, PARTICULARLY PHRASEOLOGY, SO EVERYBODY IS ON THE SAME PAGE.

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.