limiting Mach number

In addition, the combustion chamber's inlet temperature increases to very high values, approaching the dissociation limit at some limiting Mach number.

Because it had the highest limiting Mach number of any aircraft at that time, a Spitfire XI was chosen to take part in these trials.

A possible cause is that Thierfelder exceeded the airframe's limiting Mach number in a dive, perhaps while pursuing an Allied reconnaissance aircraft, leading to an irrecoverable dive.