Gas turbine propulsion system with spool coupling device

A gas turbine engine, comprising:

• a first spool;
• a second spool;
• an accessory gearbox (AG) in drive communication with the second spool, the accessory gearbox including an AG output shaft;
• and
• a spool coupling device (SCD) in drive communication with the first spool, and in drive communication with the AG output shaft, wherein the spool coupling device includes an SCD accessory dock and a transmission that is disposable in a first spool engaged configuration or in a second spool engaged configuration;
• wherein in the first spool engaged configuration, rotational drive from the first spool is provided through the transmission to the SCD accessory dock, and in the second spool engaged configuration, rotational drive from the second spool is provided through the transmission to the SCD accessory dock.

A gas turbine engine, comprising:

• a first spool;
• a second spool;
• an accessory gearbox (AG) in drive communication with the second spool, the accessory gearbox including an AG output shaft;
• a spool coupling device (SCD) in drive communication with the first spool, and in drive communication with the AG output shaft, wherein the spool coupling device includes an SCD accessory dock and a transmission;
• and
• a controller in communication with the transmission and a non-transitory memory storing instructions, which instructions when executed cause the controller to select between:
• disposing the transmission in a first spool engaged configuration wherein the first spool is engaged and rotational drive from the first spool is provided through the transmission to the SCD accessory dock;
• or
• disposing the transmission in a second spool engaged configuration wherein the second spool is engaged and rotational drive from the second spool is provided through the transmission to the SCD accessory dock.