Bell 412 question
We operate the Bell 412 EP in a variety of roles and have a question regarding the pre flight hydraulic systems checks.
According to the Bell flight manual there are 2 checks to be carried out. The preliminary check with the throttles at idle to check for uncommanded control movement or motoring whilst either system is selected off and a second check at 100%rpm to determine proper operation of the hydraulic actuators.
During the second check you are also required to check the electrical interlock, which prevents both systems from being switched off at the same time. To do this you are required to select the second system’s switch to off whilst the first is already isolated to check that the second system remains operational and vice versa.
For those of you not familiar with this aircraft the hydraulic switch panel is located on the centre console on the co-pilots side. Therefore as we operate the aircraft single pilot, this check is conducted with the left hand away from the collective.
Our concern is that whilst the likelihood of this electrical interlock failing is no doubt extremely rare, if there is a check in place to ensure the interlock is working then logically there must be a risk of it not! As the procedure stands if it did fail the aircraft would have no hydraulic assistance at 100%rpm and the collective unguarded.
Our question is could the interlock part of the second hydraulic check be carried out during the preliminary hydraulic check when the throttles are at idle?
Are there any other 412 operators out there who share our concern or are we being over cautious?