B737 fails to make crossing restr during descent in ZLC airspace.

Attributes
ACN	431193
Time
Date	199903
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	intersection : bearr
State Reference	UT
Altitude	msl bound lower : 16000 msl bound upper : 20000
Environment
Flight Conditions	VMC
Weather Elements	Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zlc.artcc
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	other other vortac
Flight Phase	descent : approach
Route In Use	arrival star : bear 3
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 4000 flight time type : 14
ASRS Report	431193
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : flight engineer pilot : instrument pilot : multi engine pilot : atp
Experience	flight time last 90 days : 180 flight time total : 18000 flight time type : 5000
ASRS Report	431001
Events
Anomaly	altitude deviation : crossing restriction not met non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	none taken : insufficient time
Supplementary
Problem Areas	Flight Crew Human Performance Weather
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

FMS was set up with en route flight planned route, including the bearr 3 arrival into salt lake city. Planned altitude at bearr was 16000 ft, as per note in flight plan. Planned descent at 300 KTS. ATC gave pilot's discretion to FL240, while we were at FL290 due to expected turbulence. I was flying at mach .73 due to occasional turbulence. The FL240 was entered into FMS but not engaged. Upon next frequency change, the controller gave restr at bearr of 16000 ft, 250 KIAS. This was entered into FMS and engaged. Aircraft started descent due to previously entered FL240. Altitude hold engaged to prevent descent because the ride wasn't bad yet and it was too early to descend. Shortly thereafter, the ride got worse and VNAV was engaged and aircraft started down about 50 mi prior to the top of descent point on the FMS. At about 2 mi from top of descent, I switched to the progress page and saw that we were almost at bearr intersection, while still at FL200, 280 KIAS. I am new to FMS aircraft and until this occurrence everything worked as expected. I failed to back up FMS by calculating my own top of descent point and did not notice what it was planning its top of descent on. All my inputs into the FMS looked good, but it is possible due to the timing of inputs that I confused it.

Original NASA ASRS Text

Title: B737 FAILS TO MAKE XING RESTR DURING DSCNT IN ZLC AIRSPACE.

Narrative: FMS WAS SET UP WITH ENRTE FLT PLANNED RTE, INCLUDING THE BEARR 3 ARR INTO SALT LAKE CITY. PLANNED ALT AT BEARR WAS 16000 FT, AS PER NOTE IN FLT PLAN. PLANNED DSCNT AT 300 KTS. ATC GAVE PLT'S DISCRETION TO FL240, WHILE WE WERE AT FL290 DUE TO EXPECTED TURB. I WAS FLYING AT MACH .73 DUE TO OCCASIONAL TURB. THE FL240 WAS ENTERED INTO FMS BUT NOT ENGAGED. UPON NEXT FREQ CHANGE, THE CTLR GAVE RESTR AT BEARR OF 16000 FT, 250 KIAS. THIS WAS ENTERED INTO FMS AND ENGAGED. ACFT STARTED DSCNT DUE TO PREVIOUSLY ENTERED FL240. ALT HOLD ENGAGED TO PREVENT DSCNT BECAUSE THE RIDE WASN'T BAD YET AND IT WAS TOO EARLY TO DSND. SHORTLY THEREAFTER, THE RIDE GOT WORSE AND VNAV WAS ENGAGED AND ACFT STARTED DOWN ABOUT 50 MI PRIOR TO THE TOP OF DSCNT POINT ON THE FMS. AT ABOUT 2 MI FROM TOP OF DSCNT, I SWITCHED TO THE PROGRESS PAGE AND SAW THAT WE WERE ALMOST AT BEARR INTXN, WHILE STILL AT FL200, 280 KIAS. I AM NEW TO FMS ACFT AND UNTIL THIS OCCURRENCE EVERYTHING WORKED AS EXPECTED. I FAILED TO BACK UP FMS BY CALCULATING MY OWN TOP OF DSCNT POINT AND DID NOT NOTICE WHAT IT WAS PLANNING ITS TOP OF DSCNT ON. ALL MY INPUTS INTO THE FMS LOOKED GOOD, BUT IT IS POSSIBLE DUE TO THE TIMING OF INPUTS THAT I CONFUSED IT.

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.