Date: 201508
Local time of day: 0001-0600
Location: L30.TRACON, NV
Flight conditions: VMC
Light: Daylight
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Initial Approach
Airspace: Class B LAS
ATC / advisory: TRACON L30
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: Pilot Not Flying; First Officer
Anomaly: ATC Issue All Types; Conflict NMAC
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Airspace Structure; Procedure
Primary problem: Ambiguous

Narrative: We were on a heading of 070 passing 10;000 ft for 8;000 ft being vectored for a Visual Approach to Runway 01R approximately 25 miles south of Las Vegas. We received a TCAS alert within two miles off our nose without an altitude. Both of us scanned in front of the aircraft; and after just a few seconds we saw a glider pass directly over us going left to right approximately 200 ft above our altitude. We immediately reported this to Approach Control but they seemed unconcerned. Approach said they had numerous reports of glider activity south of the field but never warned us of it. They said because the gliders were outside of the Class B there was nothing they could do. We would have appreciated a heads up especially considering that the frequency was not busy at the time.   We see many warnings on ATIS that do not materialize. More of an effort should be made to warn Flight Crews of potential threats if they are in progress.


Second narrative: We were on the KEPEC on a clear day; nothing unusual and the radios were rather quiet. Descending out of 10;000 ft; some 25 miles south of 1R; we received a TCAS Alert (solid amber no altitude) about two miles at our 11 o'clock and appeared to be moving towards our nose. Both sets of eyes went out. Very soon after; I picked up a glider traveling south on a direct intercept patch approximately 200 ft-300 ft above our altitude. There was no time to react. The glider at the point of intersection began a left hand turn towards the east going belly up to us. It appeared quite clearly the glider never saw us. As the Pilot Monitoring I immediately radioed Approach. This was the second glider we had seen (first was approximately one minute earlier off our right wing and was no conflict). Approach came back very non-concerned saying 'yes; we've had numerous reports of gliders;' and when pressed further; the Controller stated there was nothing they could do for the gliders were outside Class B airspace. Knowing gliders were in the area with quiet radios it is unacceptable that Approach did not pass along this key piece of information to arriving Pilots? Had we hit; there would have been loss of life. If no one reports and follows through with this and the gliders continue to choose to operate in the path of arrival traffic to Las Vegas; it may be only a matter of time.


Synopsis: B737 Flight Crew experiences a NMAC with a glider at 10000 feet 25 NM south of LAS during arrival. ATC was aware of the gliders in the area but did not inform the crew. A TCAS TA was the first indication of traffic with no altitude indication.