 Despite these modifications, the P-51Bs and P-51Cs, and the newer P-51Ds and P-51Ks, experienced low-speed handling problems that could result in an involuntary "snap-roll" under certain conditions of air speed, angle of attack, gross weight, and center of gravity.Several crash reports tell of P-51Bs and P-51Cs crashing because horizontal stabilizers were torn off during maneuvering.As a result of these problems, a modification kit consisting of a dorsal fin was manufactured.