Date: 201811
Local time of day: 1201-1800
Location: IAH.Airport, TX
Flight conditions: Marginal
Weather elements / visibility: Cloudy; Turbulence
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B IAH
ATC / advisory: Tower IAH
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Time Pressure; Situational Awareness; Distraction; Communication Breakdown; Workload
Second reporter function: Captain; Pilot Flying
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Returned To Clearance; Flight Crew Became Reoriented
Contributing factors: Human Factors; Environment - Non Weather Related; Procedure; Weather
Primary problem: Weather

Narrative: Was told to keep speed up (present speed) all the way to VANNN (250 knots). First Officer asked to slow to 210 [knots] as per arrival; but was denied or told to keep present speed. We were at 250 knots (7;000 feet) until approximately VANNN and joining the localizer. From VANNN; we had three speed reductions essentially given in one radio call - 210 [knots] to MKAYE; 180 [knots] to KERNS; and 170 [knots] to JEPNI. With all of going on with speed reductions and aircraft configuring; there was a weather cell (seemed ominous to me) on the localizer course. Captain asked me to call for a weather deviation after he deviated left. The controller denied the deviation and we turned back to course - per his heading. I believe because our speed was higher than normal; and there was a lot going on with communicating with the controller we overshot the localizer on the other side. As we began our turn back; he gave us another heading to intercept. The controller seemed upset and was talking very fast at this point. I remember I had to pause once to respond to him. We were then cleared to 3;000 feet and cleared the approach again. We were also high on the approach and lowered the gear early to get on glideslope by 3;000 feet. The aircraft behind us seemed to have the same troubles. They were eventually broke out of the approach and given a heading and altitude for a new approach. (I don't have the specifics of why their approach clearance got canceled). The controller asked if there was a problem on the approach (I was busy with flying duties at the time; and didn't have much to say); I replied we had many speed reductions to deal with.After the Captain talked to the Ops Supervisor; I also called him to get more information. Our deviation occurred around 22 miles on the approach and we were 1/2 mile off course on both sides of the localizer. He mentioned that we affected another aircraft; which I assume could be possible (I never saw any aircraft on TCAS). I asked about the weather and he said that it was broadcast several times to all aircraft that it was not a factor. I never heard that broadcast. The controller did mention after our turn back to course that it was not a factor (no turbulence reported).


Second narrative: I was the Captain on flight to IAH. I was also the Pilot Flying. We were cleared for the ILS 26L approach. We were also given 3 speed restrictions all within about 5 miles on the approach; which makes this approach quite busy. We were on our assigned speed of 210 [knots] on the localizer and rapidly approaching a small cell (TCU) centered just north of the localizer near MKAYE intersection. The cell looked to be quite turbulent; and I did not want to penetrate it so I elected to deviate slightly south of course (saw no traffic on TCAS). I asked my First Officer to get us a clearance to go around this cell and he did so. We were immediately denied and were told to turn back to the north to rejoin the course and our approach clearance was cancelled. I made a turn to the northwest but due to our speed we went through the course before I could rearm the approach which put us slightly north of course. We were recleared for the approach but now we are still fast and high. About this time we overheard [another] flight have the same problem and was not only denied; but turned off the approach. We were never given any warning about this cell; nothing! We could not deviate left or right; so we had absolutely no choice but to fly through it. We found ourselves between a rock and a hard place. After we landed; we were told to call Approach for possible pilot deviation. I called them and explained why we didn't stay on the localizer. The manager understood but said he had to file a report. My First Officer also called them for more info and the manager told him we were 1/2 mile off course both left and right at about 22 miles from the runway.Unexpected cell on approach; unexpected denial of request for weather deviation.Shut down the approach or stagger parallel traffic to that runway if there is a cell and deviations are possible


Synopsis: Air carrier flight crew reported deviating off localizer on approach to IAH due to weather.