Date: 201809
Location: ZZZ.Airport, US
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Takeoff / Launch
Airspace: Class C ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Communication Systems
Component problem: Design
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting; Communication Breakdown
Anomaly: ATC Issue All Types; Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Aircraft; Procedure
Primary problem: Ambiguous

Narrative: Approximately 400 ft after takeoff from Runway 4R at ZZZ; we got a call from ATC to switch frequencies. We were configured at flaps 25 to meet our performance criteria; and in a critical phase of flight. Pilot Monitoring (PM) called for Heading Select at the same time ATC called for us to switch to Departure. I disregarded ATC and executed command from PM. ATC called us again and I said 'Bye'. We got to level-off altitude; reconfigured to clean configuration; and I then called Departure on the radio. After check-in with Departure; I asked if Departure would mind relaying to ZZZ Tower that 'We were in an -800 with rocker switches performing a flaps 25 takeoff and expected to level off at 3000 ft. Could you please relay and just ask him to chill out?' I fully realize that 'Bye' and 'chill out' are not standard ATC terminology. There was confusion with the initial Departure Controller. A Manager; it sounded like; said 'I'd be glad to talk to him but can you expand on it?' I gave him the full story briefly stating that I didn't want to clobber the radio but we've got our hands full in our particular situation. As a former Safety Rep for six years; I've heard the same response from Crews that were in our similar situation over and over; especially when ZZZ 1 is operating in a different arrival configuration than ZZZ. Thankfully; we didn't overspeed the flaps and they didn't change our level off altitude to 2000 ft when we checked in to Departure. The adage Aviate; Navigate; and then; only then Communicate applies. Two minutes had passed; and the next Controller said 'I hate to do this to you; but we need you to call [upon landing].' I said no problem and ready to copy. The rocker switches in the -800 are unsatisfactory in my opinion. This is a large threat from a risk analysis standpoint that is more than worth the investment required. In my opinion; it's time to fix the fleet now. I can't imagine what it would have been like if both the Pilot Flying and I weren't wearing ANR headsets either. The ANR provided by my Bose and his David Clark kept us from having to hear ambient noise on takeoff. I suppose that's a side note; but true nonetheless. On landing; I called Company ATC Representative; who told me do not call the number to ATC. I gave him the number provided; he called them and mitigated the issue. [ATC rep] requested us to file a report which we were more than happy to do. Thank you for all you do to keep us safe. Grant Company traffic permission to switch from Tower to Departure without acknowledgement when departing ZZZ. Fix the rocker switches to allow for hot MIC in an -800. It's worth the investment. Make it a requirement for ZZZ ATC Personnel to jumpseat on an -800 takeoff with flaps at 25 so they get the big picture that we are task saturated on takeoff. As I understand it; there is a video [on internet] out there that shows exactly what I'm talking about. I should have used standard ATC terminology but obviously I was a little flustered.




Synopsis: 737-800 Captain reported ATC issued a request at a critical time during initial climb out. In addition; this model of aircraft has radio rocker switches that are unsatisfactory.