12 self-sealing fuel tanks could hold around 12,000 L (3,100 US gal), and eight oil tanks, two for each engine, held a total of 350 L (90 US gal). The combination of a heavy airframe and powerful engines resulted in high fuel consumption, and the P.108's performance at high altitude was mediocre, with a practical ceiling of about 6,000 m (19,700 ft) and a theoretical 8,000 m (26,300 ft). By comparison, the B-17C was capable of attaining a 3,000 m (9,840 ft) higher ceiling. The figure for the Italian bomber was comparable to contemporary bombers; the ceiling for the RAF's best bomber, the Avro Lancaster was similar, while the USAAF's B-17, B-24 and later B-29 were unusual in being able to gain such altitudes. This was due to their installed turbochargers, as well as doctrinal differences in high altitude precision bombing advocated by the United States Army Air Forces.