A B737-300 PIC turns off the localizer for runway 25L too soon when reading 6 DME on bld VOR instead...

Attributes
ACN	504500
Time
Date	200103
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : las.vortac
State Reference	NV
Altitude	msl single value : 8000
Environment
Flight Conditions	VMC
Weather Elements	other
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : l30.tracon
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer only : 25l other other vortac
Route In Use	approach : circling approach : instrument non precision approach : visual arrival star : nootn
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 220 flight time total : 11000 flight time type : 6500
ASRS Report	504500
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued alert controller : issued new clearance
Consequence	faa : reviewed incident with flight crew other
Supplementary
Problem Areas	Environmental Factor Airspace Structure Flight Crew Human Performance Weather Chart Or Publication
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Inbound to las on nootn 3, landing runways 1L&right. Instructed to intercept runway 25L localizer, track inbound to 6 mi from las and then turn 190 degrees downwind runway 1L. Instead of turning at 6 NM from las to 190 degrees, started turn at 6 NM off of boulder city VOR. After approximately 30 degrees of turn, approach asked what we were doing, said 'turning 190 degrees,' at which time they gave fly 230 degrees. I confirmed that I had heard the instructions correctly and then realized I was on the wrong NAVAID. Approach said 'no problem or conflict.' were told to look for B767 to follow visual runway 14. Uneventful approach and landing. Factors: main factor of course, wrong NAVAID. Contributory factors: used LNAV to track inbound runway 25L localizer, both pilots had been on bld VOR to monitor LNAV course tracking on nootn arrival. Turning inbound, first officer was updating information to reflect runway 1L/right instead of normal runway 25L, therefore, he was in the computer and not monitoring navigation at that moment. When established on runway 25L localizer using LNAV, switched to 111.75 and VOR/localizer to track inbound of new DME. Failed to switch second frequency to 116.9, read 6 DME off 116.7 and the rest is history. Flight conditions were clear with reduced visibility in haze and sun directly in your eyes (ie, could not see las airport or city -- basically IMC). Could it happen again? You bet. Using LNAV to navigation on nootn told to intercept a non DME localizer and turn at a point off a VOR which frequency is .20 different from NAVAID previously used. Yes it would be nice if bld 116.7 and las 116.9 frequencys were not easily misinterped because of their similar first 3 numbers. Bottom line: me -- the PF -- screwed up, kept expecting to see the airport and didn't and used wrong NAVAID. My backup -- the first officer was in the computer and also on bld VOR so when I turned at 6 DME it looked right to him.

Original NASA ASRS Text

Title: A B737-300 PIC TURNS OFF THE LOC FOR RWY 25L TOO SOON WHEN READING 6 DME ON BLD VOR INSTEAD OF THE REQUIRED 6 DME OFF THE VOR AT LAS, NV.

Narrative: INBOUND TO LAS ON NOOTN 3, LNDG RWYS 1L&R. INSTRUCTED TO INTERCEPT RWY 25L LOC, TRACK INBOUND TO 6 MI FROM LAS AND THEN TURN 190 DEGS DOWNWIND RWY 1L. INSTEAD OF TURNING AT 6 NM FROM LAS TO 190 DEGS, STARTED TURN AT 6 NM OFF OF BOULDER CITY VOR. AFTER APPROX 30 DEGS OF TURN, APCH ASKED WHAT WE WERE DOING, SAID 'TURNING 190 DEGS,' AT WHICH TIME THEY GAVE FLY 230 DEGS. I CONFIRMED THAT I HAD HEARD THE INSTRUCTIONS CORRECTLY AND THEN REALIZED I WAS ON THE WRONG NAVAID. APCH SAID 'NO PROB OR CONFLICT.' WERE TOLD TO LOOK FOR B767 TO FOLLOW VISUAL RWY 14. UNEVENTFUL APCH AND LNDG. FACTORS: MAIN FACTOR OF COURSE, WRONG NAVAID. CONTRIBUTORY FACTORS: USED LNAV TO TRACK INBOUND RWY 25L LOC, BOTH PLTS HAD BEEN ON BLD VOR TO MONITOR LNAV COURSE TRACKING ON NOOTN ARR. TURNING INBOUND, FO WAS UPDATING INFO TO REFLECT RWY 1L/R INSTEAD OF NORMAL RWY 25L, THEREFORE, HE WAS IN THE COMPUTER AND NOT MONITORING NAV AT THAT MOMENT. WHEN ESTABLISHED ON RWY 25L LOC USING LNAV, SWITCHED TO 111.75 AND VOR/LOC TO TRACK INBOUND OF NEW DME. FAILED TO SWITCH SECOND FREQ TO 116.9, READ 6 DME OFF 116.7 AND THE REST IS HISTORY. FLT CONDITIONS WERE CLR WITH REDUCED VISIBILITY IN HAZE AND SUN DIRECTLY IN YOUR EYES (IE, COULD NOT SEE LAS ARPT OR CITY -- BASICALLY IMC). COULD IT HAPPEN AGAIN? YOU BET. USING LNAV TO NAV ON NOOTN TOLD TO INTERCEPT A NON DME LOC AND TURN AT A POINT OFF A VOR WHICH FREQ IS .20 DIFFERENT FROM NAVAID PREVIOUSLY USED. YES IT WOULD BE NICE IF BLD 116.7 AND LAS 116.9 FREQS WERE NOT EASILY MISINTERPED BECAUSE OF THEIR SIMILAR FIRST 3 NUMBERS. BOTTOM LINE: ME -- THE PF -- SCREWED UP, KEPT EXPECTING TO SEE THE ARPT AND DIDN'T AND USED WRONG NAVAID. MY BACKUP -- THE FO WAS IN THE COMPUTER AND ALSO ON BLD VOR SO WHEN I TURNED AT 6 DME IT LOOKED RIGHT TO HIM.

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.

A B737-300 PIC turns off the localizer for runway 25L too soon when reading 6 DME on bld VOR instead of the required 6 DME off the VOR at las, nv.