Another downside of the PACV was the degree of maintenance it required: each hour of operation required 20 hours of maintenance, a ratio comparable to that of the C-17 Globemaster III airplane and double the 10-hour average for contemporary military helicopters. An Army evaluation found that the PACV had an operationally ready rate of 55.7 percent, and all three Army ACVs were only operational during June 1969. This maintenance requirement, which was made even worse when the vehicles suffered damage, combined with the insufficient firepower to lead an Army evaluation to conclude that "there is no hope of the [PACV/ACV] unit fighting to a satisfactory conclusion in any large engagement." The PACV was also very expensive, costing about $1 million each, as much as 13 Patrol Boat, Rivers.