Date: 202104
Local time of day: 1201-1800
Location: I90.TRACON, TX
Flight conditions: IMC
Light: Daylight
Aircraft: Helicopter
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Flight phase: Initial Climb
Airspace: Class B IAH
ATC / advisory: TRACON I90
Reporter organization: Air Taxi
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Confusion; Communication Breakdown; Distraction; Workload; Troubleshooting
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Detector: Person Air Traffic Control; Person Flight Crew
Result: Air Traffic Control Issued New Clearance; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: ATC Equipment / Nav Facility / Buildings; Aircraft; Airspace Structure; Procedure
Primary problem: ATC Equipment / Nav Facility / Buildings

Narrative: After opening my IFR flight plan the Controller cleared me [with] radar vectors climb 2;000 ft. heading 130 expect 3000 ft. [in] 10 minutes and contact Departure. I departed IFR and turned on course while climbing to 2;000 ft. At 1;000 ft.; I attempted to contact Departure but didn't get a reply. I thought maybe I wasn't high enough so I continued my climb. At 1;300 ft.; I heard the Controller talking with another aircraft so I waited until he was done and tried to make contact again. There was no reply. I confirmed I had the correct frequency and channel selected and tried again with no reply. The Controller then asked if I 'was up' and I immediately replied thinking he heard me. He didn't reply back; so I tried again to contact him. Again; no reply. He again asked if I 'was up' and I replied again with no response. At this point; I was level 2;000 ft. so I decided to contact Tower to let them know I couldn't contact Departure. The Tower Controller gave me another frequency and I contacted Departure with no issue. I was asked to climb to 3;000 ft. and was cleared to my destinationEnroute; the Controller asked me to contact him when I landed. After landing; I called him and he asked why I didn't contact him after Departure. I explained that I tried several times and that I could hear him but he clearly couldn't hear me. He then informed me that I was 400 ft. below the Minimum Vectoring Altitude shortly before I finally contacted Departure through the different frequency. I honestly don't know what I did wrong. I know for a fact I had the right frequency in because I verified it several times and asked my medic to confirm. I also checked all other switch positions and even made sure my helmet was plugged into the correct jack. Everything was correct. In addition; I could hear the departure controller so I had to be on the right frequency. From the point I was switched from one frequency to the other; there were no communication problems. I can't explain how it happened.




Synopsis: A departing Helicopter pilot reported they were initially assigned 2;000 feet then could not establish communications with ATC in a timely manner and ATC advised them they flew below the Minimum Vectoring Altitude.