The ornamental design for a convectionairflowcontrolplate, as shown and described.
FIG. 1 is a front perspective view of a convection airflow control plate within an oven in accordance with the present invention;
FIG. 2 is a front view of the convection airflow control plate within the oven of FIG. 1;
FIG. 3 is an isolation view of the convection airflow control plate of FIG. 1; and,
FIG. 4 is a cross section view of the convection airflow control plate taken along line 4-4 of FIG. 2.
The broken lines of FIGS. 1, 2 and 4 are illustrative of the visible environmental structure of the oven in which the convection airflow control plate is provided and form no part of the claimed design.