 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Inbound from a pacific flight; B757-200 suffers INS navigation degredation approaching sxc on leena arrival.
| Attributes | |
| ACN | 802145 |
| Time | |
| Date | 200808 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : sxc.vortac |
| State Reference | CA |
| Altitude | msl single value : 17000 |
| Aircraft 1 | |
| Controlling Facilities | tracon : sct.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other vortac |
| Flight Phase | descent : intermediate altitude |
| Route In Use | arrival star : leena |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Experience | flight time last 90 days : 150 flight time total : 9000 flight time type : 500 |
| ASRS Report | 802145 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : approach |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : crossing restriction not met other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | controller : provided flight assist flight crew : overcame equipment problem |
| Supplementary | |
| Problem Areas | Aircraft Flight Crew Human Performance |
| Primary Problem | Aircraft |
Narrative:
We were on leena 4 arrival cleared to cross 15 mi west of sxc at 12000 ft. At approximately 17000 ft; socal approach asked if we will make our crossing restr. Xchking the FMC and doublechk with mental math; the answer was affirmative. A couple mins later the controller asked again. At this time the PNF asked what mileage controller was showing. The mileage differed by 9-10 mi. Shortly thereafter; we were given a vector for descent to the southeast. At this time the PNF checked the onboard computer versus raw data and the raw data indeed showed the discrepancy the controller showed. Next we were cleared direct sli with no additional requests.
Original NASA ASRS Text
Title: INBOUND FROM A PACIFIC FLT; B757-200 SUFFERS INS NAV DEGREDATION APCHING SXC ON LEENA ARRIVAL.
Narrative: WE WERE ON LEENA 4 ARR CLRED TO CROSS 15 MI W OF SXC AT 12000 FT. AT APPROX 17000 FT; SOCAL APCH ASKED IF WE WILL MAKE OUR XING RESTR. XCHKING THE FMC AND DOUBLECHK WITH MENTAL MATH; THE ANSWER WAS AFFIRMATIVE. A COUPLE MINS LATER THE CTLR ASKED AGAIN. AT THIS TIME THE PNF ASKED WHAT MILEAGE CTLR WAS SHOWING. THE MILEAGE DIFFERED BY 9-10 MI. SHORTLY THEREAFTER; WE WERE GIVEN A VECTOR FOR DSCNT TO THE SE. AT THIS TIME THE PNF CHKED THE ONBOARD COMPUTER VERSUS RAW DATA AND THE RAW DATA INDEED SHOWED THE DISCREPANCY THE CTLR SHOWED. NEXT WE WERE CLRED DIRECT SLI WITH NO ADDITIONAL REQUESTS.
Data retrieved from NASA's ASRS site as of May 2009 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.