Date: 201505
Local time of day: 1201-1800
Location: ZTL.ARTCC, GA
Flight conditions: IMC
Weather elements / visibility: Turbulence; Thunderstorm; Icing
Light: Daylight
Aircraft: Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise; Descent
Airspace: Class A ZTL
ATC / advisory: Center ATL
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Distraction; Situational Awareness; Time Pressure; Communication Breakdown
Anomaly: ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Procedure; Human Factors
Primary problem: Human Factors

Narrative: En-route to ZZZ we began approaching a line of thunderstorms that extended from South Florida to Indianapolis. At FL330 our flight plan had us on the West side of these storms; and knew we eventually had to cross the frontal zone at some point in order to get on east side of the storms. With INDY Center we repeatedly asked for a left deviation to get around the North side of the building storms; and were simply ignored after several attempts. (No call back from INDY Center; nothing; other aircraft equally ignored; except for one; who ignored their INDY ATC; and told the controller; 'I am not letting you fly me through a thunderstorm'). Now we were stuck on the West side of the front and had to deviate even further to the West; with a plan to loop around the weather in South Florida; which was also building. Glad I had dispatch add another 1;000lbs fuel. Eventually had to climb to FL390 to stay above the tops/blow off; with still a 1;200 feet margin to max; altitude; and save fuel. With ATL Center; controller advised that a gap existed in the vicinity of LGC; through which several aircraft were making it through. After a good look on the radar; we proceeded through the recommended gap; SAT -54C. As we crossed the frontal zone; I noticed the airspeed rolling back; and trend vector continuing to show slower passed the clean min maneuvering speed; engines at max climb thrust. Simultaneously we began picking up ice; at least 1/4 inch on the window. I told my First Officer to request FL380 or lower immediately; as the airplane would slow to the point of not being able to maintain FL390. First Officer could not get a word in edge wise as another aircraft (previously denied by ATL ATC) was declaring to ATC they were leaving FL430 for FL410 and could not maintain altitude. SAT was now -27C and the aircraft still slowing now into the clean min man maneuver speed 'J hook'.  Exercised Captain's emergency authority. Switched off the auto pilot and began a descent. Passing FL388 First Officer was able to obtain clearance to FL380. Speed immediately began to build back up to normal; and we continued at FL380. Lowest speed I saw was 219 KTS IAS; and we did not get the 'low speed' aural warning; as the situation was corrected by then. Flight continued normally at FL380 until clear of traffic; and then descended to FL370; appropriate for direction of flight. 1. The abstinence of this controller denying several aircraft of their requests to deviate around the weather set up this whole scenario. (Presumably this controller did not want to be bothered with the pending workload of several reroutes; and the longer he delayed; the further South we would be; and eventually cross into someone else's airspace. No longer his problem!2. In future I will begin with a 'Pan; Pan; Pan' call; if unanswered 'Mayday; Mayday; Mayday'. INDY Center needs to get their act together! 3. Would have descended sooner without ATC clearance to avoid getting 15 KTS slow; at altitude.




Synopsis: Pilot reports of encountering icing conditions and not being able to get a response from ATC. Pilot descends out of assigned altitude for 1;000 feet lower to get out of icing conditions; attempts to call ATC but is difficult in doing so; eventually contacts ATC and advises them they are in an emergency descent to get out of the icing conditions.