PURPOSE: To make improvements in landing accuracy as well as to raise the ovation efficiency by making a call register impossible through an oil temperature detector operating when oil temperature in a tank is less than the set one, and operating a car when a tank oil temperature rising means continuously operates for the specified time.

CONSTITUTION: When an oil temperature detector 16 operating at less than the set temperature operates, its signal is inputted into an operation controller 18 which makes a call register unit 19 unable to be registered. Next, an oil temperature rising device 21 is operated by this controller 18, thereby increasing an oil temperature in a tank to some extent. When this oil temperature rising device 21 operates, a timer 22 operating after the elapse of the specified time operates as well, and if the oil temperature in the tank fails to go up, a car is operated at low speed by the controller 18. Then a signal is fed to a warm-up device 23, and the car is made to go up or down for warming up motion. In succession, if the oil temperature goes up owing to this warm-up motion, the oil temperature detector 16 is reset, whereby the call register unit 19 is made able to be registered by the controller 18, and thus this call register unit 19 operates into usual operation.