Date: 201812
Local time of day: 0601-1200
Location: IAH.Airport, TX
Flight conditions: VMC
Aircraft: B737 Next Generation Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class B IAH
ATC / advisory: TRACON I90
Aircraft component: Headset
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Situational Awareness
Anomaly: ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented
Contributing factors: Equipment / Tooling; Human Factors
Primary problem: Human Factors

Narrative: We were assigned different airspeeds than published per LINKK1 arrival in to Houston. Examples were 'delete airspeed restrictions; maintain 250 knots; cross fix at 6;000 [feet]; [and] then cleared for ILS 27'. We were then asked if we were going to be able to cross SYYKO at 3;000 [feet]; which I replied let me check to confirm. We were told to cancel approach clearance and given a heading and an altitude; and re-cleared for the ILS 27. I replied to ATC we were given an altitude of 6;000 [feet] and cleared for the approach which I interpreted incorrectly to mean we could maintain 6;000 [feet] until intercepting the localizer and we would descend on the glideslope at that point. I did question the First Officer (Pilot Flying) if he was going to descend via the altitudes on the approach and did not get a response. I should have spoken up louder to confirm his plan or questioned ATC before ATC questioned us. I believe a major contributor to this event was the loudness of the flight deck and one pilot (me) wearing a noise canceling headset (much better ATC communications) and the First Officer wearing the company provided headset which in my opinion is highly inadequate. From my experience; pilots that wear them have a much harder time hearing ATC communications. The company provided headset is terrible in my opinion and unacceptable; First Officer stated he did not hear 'cleared for the ILS 27' but I do believe ATC cleared us to cross a fix at 6;000 [feet] and cleared for the ILS 27 and I read it back as instructed by ATC. I questioned the First Officer but as I was questioning him; we were asked by ATC if we could make the next restriction; then taken off the approach. First Officer stated to me he did not hear cleared for the approach. I believe ATC could have been more clear; maybe state resume descent via arrival; descend via the approach; something maybe to be more clear. Part of the confusion from my part was ATC modifying the arrival speed; altitudes; then cleared or the approach. Saying that; I think I should have spoken up to ATC to confirm and spoken louder to the First Officer to confirm his intent.




Synopsis: B737NG Captain reported a missed crossing restriction after ATC altered the approach clearance.