The great demands of the overseas air forces have often left domestic AAF stations without a sufficient supply of Grade 100 gasoline. Consequently, Grade 91 gasoline has been widely used at U.S. bases, particularly for training flights. With the tempo of war increasing, Grade 91 fuel will continue to be used.

The P-40 is a perfectly safe airplane to fly with Grade 91 gas. With a thorough knowledge of its operating limits, flying with Grade 91 should give you no trouble at all. Remember, never use FULL RICH mixture control setting except in extreme emergencies when using Grade 91 gas.