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Heading track deviation when aircraft's autoplt captures the wrong localizer during radar vectoring for IAP ILS approach.
| Attributes | |
| ACN | 208037 |
| Time | |
| Date | 199204 |
| Day | Mon |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : iad |
| State Reference | VA |
| Altitude | msl bound lower : 2000 msl bound upper : 3000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : iad tower : abq |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Transport, Low Wing, 2 Turboprop Eng |
| Navigation In Use | ils localizer & glide slope : idlx Other Other |
| Flight Phase | descent : approach |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 230 flight time total : 4600 flight time type : 1900 |
| ASRS Report | 208037 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : less severe non adherence : clearance other anomaly other other spatial deviation |
| Independent Detector | other controllera other flight crewa |
| Resolutory Action | controller : issued new clearance other other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation other |
Narrative:
On approach to iad, we were given a southwest vector (approximately 240-250 degrees) to intercept the 19R localizer at iad. From our position, this meant flying diagonally across the 19L localizer, also in use. I was the PF, and at the time, the autoplt digital afcs with EFIS was engaged. When cleared on the southwest vector to intercept the 19R localizer, I armed the system for capture. The captain confirmed the correct frequencys both tuned and idented. The system captured the beam, and initiated a 40-50 degree left turn to the inbound course (190 degrees). The CDI needle showed a fly right indication, but I did not think this unusual, given our distance out. Several seconds later, the approach controller said she showed us 'intercepting the 19L localizer.' the captain confirmed that we had the correct frequencys tuned for the right side, but the controller went ahead and cleared us on the 19L approach. We re-tuned the radios and continued without incident. Afterward, I recalled being told of similar instances by other company pilots of the autoplt system capturing the beam of a parallel runway when flying across it, even though the correct navigation frequency was used. Judging from the few aircraft on the frequency, I do not believe this caused a conflict. In the future, I will be sure to monitor the autoplt's behavior more closely.
Original NASA ASRS Text
Title: HDG TRACK DEV WHEN ACFT'S AUTOPLT CAPTURES THE WRONG LOC DURING RADAR VECTORING FOR IAP ILS APCH.
Narrative: ON APCH TO IAD, WE WERE GIVEN A SW VECTOR (APPROX 240-250 DEGS) TO INTERCEPT THE 19R LOC AT IAD. FROM OUR POS, THIS MEANT FLYING DIAGONALLY ACROSS THE 19L LOC, ALSO IN USE. I WAS THE PF, AND AT THE TIME, THE AUTOPLT DIGITAL AFCS WITH EFIS WAS ENGAGED. WHEN CLRED ON THE SW VECTOR TO INTERCEPT THE 19R LOC, I ARMED THE SYS FOR CAPTURE. THE CAPT CONFIRMED THE CORRECT FREQS BOTH TUNED AND IDENTED. THE SYS CAPTURED THE BEAM, AND INITIATED A 40-50 DEG L TURN TO THE INBOUND COURSE (190 DEGS). THE CDI NEEDLE SHOWED A FLY R INDICATION, BUT I DID NOT THINK THIS UNUSUAL, GIVEN OUR DISTANCE OUT. SEVERAL SECONDS LATER, THE APCH CTLR SAID SHE SHOWED US 'INTERCEPTING THE 19L LOC.' THE CAPT CONFIRMED THAT WE HAD THE CORRECT FREQS TUNED FOR THE R SIDE, BUT THE CTLR WENT AHEAD AND CLRED US ON THE 19L APCH. WE RE-TUNED THE RADIOS AND CONTINUED WITHOUT INCIDENT. AFTERWARD, I RECALLED BEING TOLD OF SIMILAR INSTANCES BY OTHER COMPANY PLTS OF THE AUTOPLT SYS CAPTURING THE BEAM OF A PARALLEL RWY WHEN FLYING ACROSS IT, EVEN THOUGH THE CORRECT NAV FREQ WAS USED. JUDGING FROM THE FEW ACFT ON THE FREQ, I DO NOT BELIEVE THIS CAUSED A CONFLICT. IN THE FUTURE, I WILL BE SURE TO MONITOR THE AUTOPLT'S BEHAVIOR MORE CLOSELY.
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.