This is an RC heli ESC? What size heli, and what kind of controller is it (or just voltage/current rating).
Basic guidelines...get a NMOS with the same...
-package (duh!)
-at least the same voltage rating
-equal or less RDson at equal or less gate voltage (pay no attention to the current rating given...the way they got it can't be trusted)
-equal or less "Total Gate CHarge" at similar voltage conditions to those given in the datasheet for that parameter
You want to balance the 3rd and 4rth points because one determines how much the transistor heats up from conducting and the other determines how much it heats up from switching on/off. SInce you don't have the design of the ESC, you don't know why or how they balanced the two parameters, so you have to stick with what they used. If you knew, then you could choose a different balance between the two parameters...but you don't
IRF7402 comes close.