AN ACR DC9 FLC HAS THEIR ACFT STRIKE THE RUDDER OF AN A320 DURING A PWRBACK. THE A320 WAS AWAITING TAXI CLRNC AND IT ALSO HAD TO RETURN TO THE GATE FOR MAINT.

Narrative

ACFT WAS CLRED TO PWR BACK FROM ATC APPROX XA50. GND SIGNAL PERSON GAVE THE SIGNAL CLRED TO PWR BACK FROM GATE. IN ACCORDANCE WITH SOP; CAPT INITIATED PWRBACK SEQUENCE. SIGNAL PERSON INDICATED TO SLOW ACFT WITH FORWARD WAND MOVEMENTS. AS ACFT SLOWED IT STRUCK ACFT BEHIND US. SUPPLEMENTAL INFO FROM ACN 379555: WHILE AWAITING TAXI CLRNC; MSP GND CTL ADVISED US THAT COMPANY REQUESTED THAT WE RETURN TO THE GATE FOR AN INSPECTION. AFTER RETURNING TO THE GATE; MAINT ADVISED THAT OUR RUDDER HAD BEEN STRUCK DURING A PWRBACK OP BY A DC9. EVEN DURING IDEAL CONDITIONS; THE SPACE BEHIND OUR ACFT AND THE GREEN CONCOURSE SEEMED INADEQUATE FOR ACFT MOVEMENT; AND ESPECIALLY HAZARDOUS FOR PWRBACK OPS. THE ONLY UNUSUAL FEELINGS EXPERIENCED ON OUR ACFT WERE 2 BUFFETING GUSTS SEPARATED BY APPROX 1 MIN; CAUSED BY THE FORWARD THRUSTS OF THE DC9. WITH OUR PARKING BRAKE SET; AND NO ACFT MOVEMENT HAVING OCCURRED ON EITHER OUR PORT OR STARBOARD SIDE OR IN FRONT OF US; AND BELIEVING IT INCONCEIVABLE THAT THRUST FROM BEHIND US HAD BUFFETED THE ACFT; IT WAS ASSUMED THAT GUSTS WERE CAUSED BY THE HVY STORM OVER THE MSP ARPT.