Removing or reinstalling the padlock on the holster?
That's apparently required every time the cockpit door is opened in flight, such as when one of pilots needs to answer a call of nature, or get a cup of coffee or a soft drink from one of the cabin crew.Info here
The Holster, (with H&K USP-40 and required padlock)
The insane procedures required by the TSA demands that our pilots to lock and then un-lock their .40 side arms was and is a solid recipe for disaster.
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Putting a gun into a holster and then threading a padlock through the trigger and trigger-guard is required every time the pilots enter or leave the cockpit.