Narrative:

Near midair experience by commercial airline flight departing slc for las. Medium large transport climbing through 13500' MSL encountered small aircraft on identical heading southeast of slc. Air carrier reduced rate of climb to avoid collision, passing 50-100' directly below small aircraft. Slc approach control called traffic prior to event; however, no altitude was reported. Subsequent conversation with ATC revealed small aircraft was transmitting squawk intermittently. When you are able to differentiate aircraft type, color and striping, you're too close for comfort at 300K. Aside from requiring mode C xponders and mandating their use by all who fly, cockpit vigilance is the only recommendation made by this pilot.

Related reports:

Google
 

Original NASA ASRS Text

Title: NMAC.

Narrative: NEAR MIDAIR EXPERIENCE BY COMMERCIAL AIRLINE FLT DEPARTING SLC FOR LAS. MLG CLBING THROUGH 13500' MSL ENCOUNTERED SMA ON IDENTICAL HDG SE OF SLC. ACR REDUCED RATE OF CLB TO AVOID COLLISION, PASSING 50-100' DIRECTLY BELOW SMA. SLC APCH CTL CALLED TFC PRIOR TO EVENT; HOWEVER, NO ALT WAS RPTED. SUBSEQUENT CONVERSATION WITH ATC REVEALED SMA WAS XMITTING SQUAWK INTERMITTENTLY. WHEN YOU ARE ABLE TO DIFFERENTIATE ACFT TYPE, COLOR AND STRIPING, YOU'RE TOO CLOSE FOR COMFORT AT 300K. ASIDE FROM REQUIRING MODE C XPONDERS AND MANDATING THEIR USE BY ALL WHO FLY, COCKPIT VIGILANCE IS THE ONLY RECOMMENDATION MADE BY THIS PLT.

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.