Date: 201407
Local time of day: 1201-1800
Location: IAH.Airport, TX
Flight conditions: VMC
Light: Daylight
Aircraft: Medium Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class E ZHU
ATC / advisory: Center ZHU
Second aircraft: Small Transport; Low Wing; 2 Turbojet Eng
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Distraction
Second reporter function: Pilot Flying; First Officer
Anomaly: ATC Issue All Types; Conflict NMAC; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance
Result: Flight Crew Returned To Clearance
Contributing factors: Aircraft; Procedure
Primary problem: Procedure

Narrative: While on the climbout from IAH on the WYLSN ONE Departure; we were given a clearance to climb and maintain 16;000 feet. At 16;000 feet with the autopilot engaged; I noticed on my TCAS an aircraft at our two o'clock 400 feet above. I told my First Officer and ask him if he had that aircraft in sight. He said he did not. Right before inquiring with ATC we got a Resolution Advisory 'RA'. I 'TCS' overrode the autopilot and followed our escape guidance and we descended about 500-800 feet.While I was executing the escape maneuver I told my First Officer to notify ATC and tell them that we got a RA and that we were complying and descending. After we were cleared of conflict I started the climb to 16;000 feet and I told my First Officer to notify ATC that we were climbing back to our assigned altitude of 16;000 feet. I inquired about the incident with ATC and he said that he showed the traffic being at 16;500 feet and us being at 16;000 feet. Not once prior or after the incident did ATC informed us about traffic only when we inquired. That aircraft also reported having us on his TCAS 300 feet below. We continued the flight without any further incident. ATC needs to keep the required separation between airplanes in controlled airspace.


Second narrative: 10-15 minutes after takeoff and level at 16;000 feet. With no advanced/prior notice from ATC; the TCAS said 'Traffic.'  The other aircraft appeared to be at our 1 to 2 o'clock and on an intercept with us on the TCAS.  With 2-5 seconds the target then changed to RED and we got the 'Traffic; DESCEND!' RA with guidance on PFD.  Captain TCS'd the yoke and followed the guidance down; descending to 15;000 feet.  During the descent I continued to look for the traffic (which I did not see) and noticed we were within 300 feet.  I called out to ATC to notify them of the RA.  The other aircraft was a business jet; they also called out an RA to Climb. When TCAS cleared we returned to our assigned altitudes and queried ATC.  The business jet put the miss at 300 feet; we thought it was possibly 200 feet to 300 feet; either way the Controller said they calculated 'at 500 feet' or something to that effect with what we sensed was only slight concern.  ATC had no answers to why this happened to either inquiry by the business jet or us.


Synopsis: Pilot report of a NMAC with a TCAS RA in which they responded to and resolved.  ATC never issued a traffic call; even though the Controller observed the traffic.