Air carrier aircraft approachs other traffic deviating WX in las ZLA airspace.

Attributes
ACN	413180
Time
Date	199809
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : las
State Reference	NV
Altitude	msl bound lower : 14000 msl bound upper : 16000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other cruise other
Route In Use	enroute airway : zla
Flight Plan	IFR
Aircraft 2
Make Model Name	Starship Model 2000
Operating Under FAR Part	other : unknown
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp pilot : instrument
Experience	flight time last 90 days : 160 flight time total : 12000 flight time type : 3300
ASRS Report	413180
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : airborne less severe other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Miss Distance	horizontal : 750 vertical : 150
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

We were level at 16000 ft MSL, deviating around buildups. All of a sudden we saw a twin (beech starship) pass right to left in front of us -- close -- and he appeared to be co- altitude. We immediately looked at the TCASII display, and it indicated 14000 ft, 2000 ft below us! That's not what it looked like. We asked center to verbally confirm with the other pilot that he was at 14000 ft, which he did. We then looked at our own altimeters, etc, and could not determine any reason for the discrepancy. Both of us are convinced we were very close to being co-altitude. We could see the type and color of the other aircraft.

Original NASA ASRS Text

Title: ACR ACFT APCHS OTHER TFC DEVIATING WX IN LAS ZLA AIRSPACE.

Narrative: WE WERE LEVEL AT 16000 FT MSL, DEVIATING AROUND BUILDUPS. ALL OF A SUDDEN WE SAW A TWIN (BEECH STARSHIP) PASS R TO L IN FRONT OF US -- CLOSE -- AND HE APPEARED TO BE CO- ALT. WE IMMEDIATELY LOOKED AT THE TCASII DISPLAY, AND IT INDICATED 14000 FT, 2000 FT BELOW US! THAT'S NOT WHAT IT LOOKED LIKE. WE ASKED CTR TO VERBALLY CONFIRM WITH THE OTHER PLT THAT HE WAS AT 14000 FT, WHICH HE DID. WE THEN LOOKED AT OUR OWN ALTIMETERS, ETC, AND COULD NOT DETERMINE ANY REASON FOR THE DISCREPANCY. BOTH OF US ARE CONVINCED WE WERE VERY CLOSE TO BEING CO-ALT. WE COULD SEE THE TYPE AND COLOR OF THE OTHER ACFT.

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.