"Chorbington" said:
"I know about that regulation. We all know about that regulation. However, such regulation will not stop "some" captains allowing the nurse to "practice". The captains have stated that they prefer dual controls so that the nurse can take control in case of captain being unable to fly. Question is, when will the nurse be allowed to practice landing? Only chance to do so is during an actual HEMS flight (possibly back to base after service).

A regulation prohibiting dual controls will fix the problem, allowing dual controls but not allowing nurse to touch them will not fix it, as I, and most of us, know for a fact that the captains will want to teach them basics."

The regulation doesn't prohibit the second set of controls, and I know it, but Citation of US FAR

"§ 135.115
Manipulation of controls.
No pilot in command may allow any person to manipulate the flight controls of an aircraft during flight conducted under this part, nor may any person manipulate the controls during such flight unless that person is—
(a) A pilot employed by the certificate holder and qualified in the aircraft; or
(b) An authorized safety representative of the Administrator who has the permission of the pilot in command, is qualified in the aircraft, and is checking flight operations.

Title 14 published on 2012-01-01"

When one or two PICs have their positions put on the line because the practice of unofficial flight instruction has come to official attention, a different light will shine.
I have yet to hear a professionally sound reason defending the practice of allowing somebody NOT authorized by the aircraft owner and my employer to ever touch the controls, ever- period. "Captains will want to teach them basics" is the "big watch syndrome".

Right seat single pilot stations having the collective and engine controls in a more or less shared area with passengers are a constant risk. I can't tell you how many times I've had correct inadvertent collective manipulation or obstruction. The experience means I am constantly defending that one vulnerable control. Having duals installed magnifies that constant risk, especially in EMS. The medical crew is appropriately focused on patient care, which will prove at some point to be the distraction that leads to an accident attributable to the second set of controls. Perhaps that event will generate a regulation (aviation rules are written in blood) and the inconvenience and expense of removing redundant controls will be required.