Boeng 737 Trip Reminder Indicator
/Trip reminder indicators are an airline option that can be inserted to the upper portion of the yoke on both the Captain and First Officer side. The indicator is a manual three digit memory device.
Initially used to remember the flight number of the flight, they were rarely used and eventually phased out of service.
The pilot uses his thumb to move the three segmented dials to indicate the flight number. I am told that when flight numbers began moving into 4 digits the devices were replaced with 4 digit indicators or their use discontinued.
I find the trip indicator very helpful and use it as a prompt to remember the landing speed (Vref). After Vref has been calculated I scribe the speed into the trip indicator.
The indicator is backlit from three 5 Volt incandescent bulbs, and it's a basic task to run a wire from the rear of the indicator through the yoke and column to a 5 volt power supply. Other than a power wire, no other configuration needs to be done.
Although the trip reminder indicator is a very small addition, it's pieces of equipment such as this that provide increased immersion.