PA-31-350 pilot reported sections of the right engine cowling detached from the aircraft affecting aircraft control. Pilot was able to maneuver for a safe landing.

Narrative

I was transporting my aircraft from ZZZ1 (maintenance facility) where it had just undergone minor maintenance. After a thorough preflight of the aircraft; I found it in airworthy condition for the flight. The aircraft was being flown back to ZZZ where it is stored. It was VFR conditions for the 35 Minute flight back. I departed approximately XA00 local and received VFR flight following from ZZZ Approach enroute to ZZZ through the class B airspace; I entered a 45-degree entry for a left downwind to runway XX at ZZZ descending through 2000 feet for pattern altitude as per ZZZ tower instructions. Upon entry into the pattern; I experienced a complete detachment of the forward right engine cowling followed by a partial detachment of the top right engine cowling. The top cowling began to create significant drag forces on the aircraft; so I reduce power to idle on the right engine and had significant difficulty maintaining directional control. As I maneuvered the aircraft directly towards the airport; I requested priority handling and stated that I needed to land immediately on Rwy XY (longest available runway). The tower at ZZZ immediately cleared me to land. Rwy XY was needed versus the initially assigned Rwy XX due to its length and my higher-than-normal approach speed in order to maintain adequate directional control. My concern for advising ATC was to prevent further detachment of the partially attached right engine cowling into the tail section.I completed the Landing safely and exited Rwy XY onto taxiway 1. I came to a completely stop and asked CFR (Crash Fire Rescue) if they would verify no fuel or oil leaks were present. No leaks were reported so I began to taxi to the ramp but was having difficulty moving the aircraft in a straight line. I suspected nose wheel or a tire malfunction and had the aircraft towed to the maintenance facility on the field. No injuries or damage to property on the ground existed. The only visible damage was to the right engine cowling. The maintenance facility in ZZZ1 was contacted and after they are doing a detailed inspection of the damage on Day 4 to determine the cause of the cowling detachment inflight.