As a result , the RTU operated the Mustangs above 5,000 ft. using them mainly for air - to - air gunnery .
The only problem encountered with the Mustang involved excess cockpit beat caused by the aircraft 's bubble canopy during the summer .
The RTU operated the Mustangs above 5,000 ft. using them mainly for air - to - air gunnery .
The only problem encountered with the Mustang involved excess cockpit beat caused by the aircraft 's bubble canopy during the summer .