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B727 flight crew with omega navigation advises ATC, lax approach, that navigation signals for IAP-ILS approach procedure-STAR are not being received. Approach controller offers flight assist, radar vectoring.
| Attributes | |
| ACN | 355860 |
| Time | |
| Date | 199611 |
| Day | Sat |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : lax |
| State Reference | CA |
| Altitude | msl bound lower : 1500 msl bound upper : 15000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : lax |
| Operator | common carrier : air carrier |
| Make Model Name | B727 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | descent : approach descent other |
| Route In Use | arrival other enroute : on vectors enroute : direct |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : flight engineer pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 160 flight time total : 12000 flight time type : 4000 |
| ASRS Report | 355860 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 360 flight time total : 5000 flight time type : 80 |
| ASRS Report | 354377 |
| Events | |
| Anomaly | aircraft equipment problem : less severe non adherence : published procedure non adherence other other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance controller : provided flight assist flight crew : overcame equipment problem other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation other |
Narrative:
This is an automation-ATC handling problem. We were en route slc to lax, approximately 70 mi southwest of mlf when we were cleared direct to civet, civet 1 arrival to lax. We used omega navigation to proceed direct to civet. Although we could receive lax VOR (113.6) we did not receive lax localizer-DME (109.9) and were unable to adequately define civet or fly the arrival (no DME -- can't make stepdowns, no ldc -- can't define inbound course). We informed the controller of the situation and he offered us radar vectors to a visual final. We accepted. Omega is normally switched off in the terminal area because of poor accuracy, we had left it on as a backup to radar vectors and the lax VOR. We started receiving lax DME at about 37 DME but still did not have reliable localizer data on either side of the cockpit. The controller worked with us to bring us in lax. He did a fine job. At approximately 13 DME on the first officer side only, our ILS localizer displacement began to jive with the controller's instructions. The controller offered us the inboard runway visual approach. We accepted and dialed in that ILS frequency as well. As I dialed in my ILS, I noticed that omega was still supplying data to my HSI. I immediately pushed the omega switch light to de-select it. The so then stated, 'well, that is the very next item on our approach checklist.' flying into the sun while landing west at lax in the afternoon, it was difficult to see the omega radio-navigation switch light position in the bright sunlight. This radio-navigation switch light was far too dim. I wrote it up in the aircraft logbook for lamp replacement. This situation could have been worse. Thank goodness we had informed the controller approaching civet that we had inadequate data available for the arrival and were accepting radar vectors to the field while we tried to work out why our displays were not right. The first officer's display should have indicated or received lax (109.9) at least by civet. It did not. The so should have actively assisted us in dynamically working our approach checklist. I should have noted the omega still directing my displays. Splitting the navigation with the right side verifying with raw data what the left side does. Processed data should have worked. This time it did not. We followed a strategy of 'elegant degradation,' eventually relying on controller instructions and visual approach.
Original NASA ASRS Text
Title: B727 FLC WITH OMEGA NAV ADVISES ATC, LAX APCH, THAT NAV SIGNALS FOR IAP-ILS APCH PROC-STAR ARE NOT BEING RECEIVED. APCH CTLR OFFERS FLT ASSIST, RADAR VECTORING.
Narrative: THIS IS AN AUTOMATION-ATC HANDLING PROB. WE WERE ENRTE SLC TO LAX, APPROX 70 MI SW OF MLF WHEN WE WERE CLRED DIRECT TO CIVET, CIVET 1 ARR TO LAX. WE USED OMEGA NAV TO PROCEED DIRECT TO CIVET. ALTHOUGH WE COULD RECEIVE LAX VOR (113.6) WE DID NOT RECEIVE LAX LOC-DME (109.9) AND WERE UNABLE TO ADEQUATELY DEFINE CIVET OR FLY THE ARR (NO DME -- CAN'T MAKE STEPDOWNS, NO LDC -- CAN'T DEFINE INBOUND COURSE). WE INFORMED THE CTLR OF THE SIT AND HE OFFERED US RADAR VECTORS TO A VISUAL FINAL. WE ACCEPTED. OMEGA IS NORMALLY SWITCHED OFF IN THE TERMINAL AREA BECAUSE OF POOR ACCURACY, WE HAD LEFT IT ON AS A BACKUP TO RADAR VECTORS AND THE LAX VOR. WE STARTED RECEIVING LAX DME AT ABOUT 37 DME BUT STILL DID NOT HAVE RELIABLE LOC DATA ON EITHER SIDE OF THE COCKPIT. THE CTLR WORKED WITH US TO BRING US IN LAX. HE DID A FINE JOB. AT APPROX 13 DME ON THE FO SIDE ONLY, OUR ILS LOC DISPLACEMENT BEGAN TO JIVE WITH THE CTLR'S INSTRUCTIONS. THE CTLR OFFERED US THE INBOARD RWY VISUAL APCH. WE ACCEPTED AND DIALED IN THAT ILS FREQ AS WELL. AS I DIALED IN MY ILS, I NOTICED THAT OMEGA WAS STILL SUPPLYING DATA TO MY HSI. I IMMEDIATELY PUSHED THE OMEGA SWITCH LIGHT TO DE-SELECT IT. THE SO THEN STATED, 'WELL, THAT IS THE VERY NEXT ITEM ON OUR APCH CHKLIST.' FLYING INTO THE SUN WHILE LNDG W AT LAX IN THE AFTERNOON, IT WAS DIFFICULT TO SEE THE OMEGA RADIO-NAV SWITCH LIGHT POS IN THE BRIGHT SUNLIGHT. THIS RADIO-NAV SWITCH LIGHT WAS FAR TOO DIM. I WROTE IT UP IN THE ACFT LOGBOOK FOR LAMP REPLACEMENT. THIS SIT COULD HAVE BEEN WORSE. THANK GOODNESS WE HAD INFORMED THE CTLR APCHING CIVET THAT WE HAD INADEQUATE DATA AVAILABLE FOR THE ARR AND WERE ACCEPTING RADAR VECTORS TO THE FIELD WHILE WE TRIED TO WORK OUT WHY OUR DISPLAYS WERE NOT RIGHT. THE FO'S DISPLAY SHOULD HAVE INDICATED OR RECEIVED LAX (109.9) AT LEAST BY CIVET. IT DID NOT. THE SO SHOULD HAVE ACTIVELY ASSISTED US IN DYNAMICALLY WORKING OUR APCH CHKLIST. I SHOULD HAVE NOTED THE OMEGA STILL DIRECTING MY DISPLAYS. SPLITTING THE NAV WITH THE R SIDE VERIFYING WITH RAW DATA WHAT THE L SIDE DOES. PROCESSED DATA SHOULD HAVE WORKED. THIS TIME IT DID NOT. WE FOLLOWED A STRATEGY OF 'ELEGANT DEGRADATION,' EVENTUALLY RELYING ON CTLR INSTRUCTIONS AND VISUAL APCH.
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.