A CRJ-200 Captain reported receiving a non-essential company message at a high workload time in descent. His complaint to the Chief Pilot fell on deaf ears.

Narrative

The Company Scheduling personnel sent a unnecessary message via ACARS during a critical phase of flight while we were trying to descend from FL180 to 13;000 FT and circumnavigate several thunderstorm cells on the STAR. The message was about trying to involuntarily assign me for a trip [in the future]. This caused us to be momentarily distracted and almost miss a clearance. There is no reason for this notification not to be sent once we were on the ground. It was totally non-essential to the flight and due to the severe under staffing at this company. The flight continued without interruption safely due to the professionalism and skill of this crew. However; this does not exempt the Company from the safety violation this created. When I brought this to the attention of Chief Pilot he laughed at me and told me the FAA has signed off on this type of operation as safe so I was wrong. I told him that I believe it to be a safety issue and that the communication was completely non-essential. This kind of behavior from management pilots at this company is becoming commonplace and needs to be curtailed before this kind of incident causes a violation or worse. The company is using unsafe and unethical scheduling and operational practices to communicate non essential information to crews at inappropriate and unsafe times. They claim the FAA thinks its just fine.