What this Zener diode does for your board
It handles 60A peak pulse current, making it a solid choice for general-purpose transient suppression on a DC rail or signal line. That temperature grade suits it for avionics, downhole, or military gear where the board sees thermal cycling.
The 17.6V minimum breakdown voltage sets the threshold where the diode starts conducting — below that it's essentially an open circuit. The 20.6V clamping voltage is the peak the protected node sees during a pulse; if your downstream silicon is rated for 22V or higher, you have margin. The single unidirectional channel handles one polarity; for bidirectional clamping you'd need two in anti-series or a TVS array.
No official second-source or direct replacement is listed, but the DO-13 footprint is a common industry standard — a cross-check against other 1500W Zener diodes in the same package is straightforward if you need an alternate.