Pilot Director Indicator as used with C-1 Autopilot, WWII B-29, B-24. B-17 PV-2 Harpoon Ammeter DC 0-10 Amps Weston

Ammeter DC 0-10 Amps Weston model 301

the narrower pointer which indicates airspeed in 10 km/h increments rests behind the thick pointer

It is in exception condition

such as the F7F Tigercat fighter and versions of the PBY Catalina and PBM-5 Mariner patrol bombers (see illustration from the F7F flight manual dated 1947)

Do your own research to confirm

Pilot Director Indicator as used with C-1 Autopilot, WWII B-29, B-24. B-17 PV-2 Harpoon Ammeter DC 0-10 Amps WestonThe Pilot Director Indicator (PDI) was used during WWII in bombers of the US Army Air Force , including heavy bombers B 17 Flying Fortress, B 24 Liberator, and B 29 Superfortress and medium bombers B 25 Mitchell and B 26 Marauder, and US Navy's PBY5A Catalina and PB4Y Privateer. The PDI was located on the pilots instrument panel, and received signals from the bombardier to indicate his desired course changes, left or right, to obtain an accurate bomb