An MD80 crew while flying the pdz arrival to lax experienced an FMS navigation error.

Attributes
ACN	519789
Time
Date	200107
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	intersection : tejay
State Reference	CA
Aircraft 1
Controlling Facilities	tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Flight Phase	descent : approach ground : preflight
Route In Use	arrival star : pdz.pdz 4
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : sct.tracon
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	519789
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	non adherence : published procedure non adherence : clearance other spatial deviation
Independent Detector	other controllera other flight crewa other flight crewb
Resolutory Action	flight crew : returned to intended or assigned course
Consequence	faa : reviewed incident with flight crew other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

Location: pdz 4 arrival, landing runway 25L. At tejay, approach called traffic ahead over arnes. While looking for the traffic, I noticed we had turned direct hunda from tejay. I directed the first officer to come right and I put arnes back in. First officer turned right to arnes and wisely went to raw data to intercept the localizer. Unfortunately, the turn to arnes set up for an overshoot of the runway 25L localizer. The first officer continued the left turn to reintercept. Approach asked us to confirm reintercepting. No loss of separation was noted. Apparently the first officer had selected the ILS runway 25L on the arrival page of the gfms sometime on the arrival. This caused the deletion of key arrival points. It re-emphasizes the need to verbalize all changes to the predep routing so that both crew members concur with the new routing. The first officer was not aware of the corruption of the arrival route caused by the selection of the ILS. The short term solution is not to select the ILS. But it highlights what I believe is a problem. All 4 landing rtes on the pdz 4 go over arnes. So why would the selection of any of them cause this point to be deleted. The same holds true for arrs into dfw. Selection of the ILS can delete all arrival points inside the feeder fix. Even if you are not going to fly over all of them -- what harm is done by not automatically deleting them?

Original NASA ASRS Text

Title: AN MD80 CREW WHILE FLYING THE PDZ ARR TO LAX EXPERIENCED AN FMS NAV ERROR.

Narrative: LOCATION: PDZ 4 ARR, LNDG RWY 25L. AT TEJAY, APCH CALLED TFC AHEAD OVER ARNES. WHILE LOOKING FOR THE TFC, I NOTICED WE HAD TURNED DIRECT HUNDA FROM TEJAY. I DIRECTED THE FO TO COME R AND I PUT ARNES BACK IN. FO TURNED R TO ARNES AND WISELY WENT TO RAW DATA TO INTERCEPT THE LOC. UNFORTUNATELY, THE TURN TO ARNES SET UP FOR AN OVERSHOOT OF THE RWY 25L LOC. THE FO CONTINUED THE L TURN TO REINTERCEPT. APCH ASKED US TO CONFIRM REINTERCEPTING. NO LOSS OF SEPARATION WAS NOTED. APPARENTLY THE FO HAD SELECTED THE ILS RWY 25L ON THE ARR PAGE OF THE GFMS SOMETIME ON THE ARR. THIS CAUSED THE DELETION OF KEY ARR POINTS. IT RE-EMPHASIZES THE NEED TO VERBALIZE ALL CHANGES TO THE PREDEP ROUTING SO THAT BOTH CREW MEMBERS CONCUR WITH THE NEW ROUTING. THE FO WAS NOT AWARE OF THE CORRUPTION OF THE ARR RTE CAUSED BY THE SELECTION OF THE ILS. THE SHORT TERM SOLUTION IS NOT TO SELECT THE ILS. BUT IT HIGHLIGHTS WHAT I BELIEVE IS A PROB. ALL 4 LNDG RTES ON THE PDZ 4 GO OVER ARNES. SO WHY WOULD THE SELECTION OF ANY OF THEM CAUSE THIS POINT TO BE DELETED. THE SAME HOLDS TRUE FOR ARRS INTO DFW. SELECTION OF THE ILS CAN DELETE ALL ARR POINTS INSIDE THE FEEDER FIX. EVEN IF YOU ARE NOT GOING TO FLY OVER ALL OF THEM -- WHAT HARM IS DONE BY NOT AUTOMATICALLY DELETING THEM?

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.