KR-87 receivers with serial numbers above 10999 or with Mod 3 have incorporated a change in flight timer operation. Instead of the flight timer resetting to zero by an external switch, the flight timer will stop and hold on the accumulated time. The only way to reset the flight timer to 0 in such units is to turn the KR-87 off and then back on. This method of operation will enable those who have the flight timer connected to the landing gear or squat switch to be able to note their flight time after landing. If this feature is not desired, simply leave pins J and K on the KR-87 rear connector open. This will cause the flight timer to begin counting when the KR 87 is turned on and will continue until it is turned off or the power is removed.