Date: 201511
Local time of day: 0001-0600
Location: GRR.Airport, MI
Flight conditions: VMC
Light: Night
Aircraft: Medium Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class E GRR
ATC / advisory: TRACON GRR
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Situational Awareness
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Company Policy; Human Factors; Weather
Primary problem: Company Policy

Narrative: We were the first aircraft to board and push back. Tower had just opened; 5 minutes before we closed the main cabin door. Tower asked us for what runway we prefer. Due to calm winds and direction of flight; I had already planned for Runway 26L. We were given taxi instructions to taxi via Victor; cross runway 17; Lima; Delta to 26L. Halfway during our taxi; tower had asked us; if we needed to deice. We said negative. Tower said; roger; continue to runway 26L. I asked the First Officer (FO); if he saw any frost/ ice. He replied back; there was none present. He said he checked and saw none. I taxied with cowls and wings on; as an extra safety measure; as it was below 5 degree Celsius. Even though there was no visible moisture and clear skies. After departing Runway 26L; we heard that loud; annoying; com panel whistle sound. After 10;000 feet; I asked my FO; if he would inform operations in Grand Rapids; that they did not close the com panel door. I was the flying pilot and said I have the radios and controls. He came back and informed me that; operations said; we departed with a mandatory deice in effect. At no time was I told; we needed to get deiced. At no time; did I see any ice/ frost present. When we arrived to the plane via jet bridge. We had to wait for a ground crew to guide the jet bridge to the plane. I was able to see the plane clearly. At no time did I see frost or ice. The ground was dry and frost/ ice free. No salts were used or present. So I told the FO; that he has the radios and controls; while I go offline and talk with operations. When I contacted ops. He did not want to talk about the panel being left opened. He argued with me that there was a mandatory deice in effect. I told him we had no frost/ ice. He said it was mandatory. No one told me this. It was not on the release or NOTAMs. Nor; did ground crew advise of such. Even so; there was no frost and ice. I saw no one getting deiced. I heard no one calling for deice. If in doubt; I would deice. So the mandatory deicing may have took effect; after we departed. ATIS Alpha; did not indicated any mandatory; deicing operations in effect.


Second narrative: When we arrived at the bottom of the jet bridge the gate agent pulled up the jet bridge to the aircraft for us to be able to board the aircraft. At this time the Tower was still closed and not scheduled to open for another ~20 minutes. After getting situated inside the cockpit I proceeded outside to do my walk around of the aircraft and accomplish the security search for the first flight of the day. During my preflight inspection using a high powered white flashlight; I noticed nothing that affects the airworthiness and no presence of ice or frost on the aircraft. I specifically remember making sure that the leading edges including the top and bottom of the wings were clean to include the vertical/horizontal stabilizers. After I completed my walk around; I proceeded to the cockpit to attend to my other duties. As soon as Tower opened for operation I obtained ATIS and clearance from clearance delivery and no indications of active de/anti-icing procedures were observed. About 5 minutes into taxiing to the active runway; ground control asked us if we needed to deice to which we replied with 'negative'. The Captain verified with me if I observed any frost or ice to which I replied no. The Captain elected to use wing and cowl anti ice shortly before takeoff during our taxi but not takeoff as a precaution. During our initial climb we observed a high pitch noise coming from the external communications panel indicating that the ground crew failed to close it properly. After we climb out of sterile cockpit environment the Captain took the controls and radios and asked me to contact GRR Operations to extend a courtesy call to them. I informed the GRR operations employee about the open panel and the fatiguing noise it accompanies to which he informed us that we departed while mandatory deicing was in effect. I immediately informed the Captain who then transferred the radios and controls to me while he contacted operations to get more insight.


Synopsis: The crew departed from GRR while a mandatory deicing procedure was reportedly in effect; though the aircraft was clean and there was no precipitation.