Original Message

there are documented cases were NVG filters "dimmed" the caution and master warning panel lights and made them "unoticeable" in certain ambient lighting. Plus same for the audio from the warning panel as it went off same volume for radios. This is not the first time this has happened but not necessarily the cause here. Just one guess. Since all the MR blades appeared to be sheared at the rotor shaft that would indicate power from at least one engine.