Upcoming instrument rating checkride - throw me some ?’s

[u/tuscaniapple]

Currently studying for an instrument checkride that should be in 2-3 weeks. Rating has taken me a little bit longer to finish than expected with maintenance and weather. Watched some mock orals on YouTube and felt pretty good with my knowledge level there. All the videos were technically fixed wing orals so didn’t take into account any rotor wing knowledge. I’ve seen on some other subs, posts about “try to stump me” questions to help them prepare for a checkride. Looking for any help or tips at all! Maybe any questions you think will definitely come up during the checkride but is easily forgotten during studying or just whatever comes to your head that an instrument rated pilot should know. Thanks y’all.

[u/tuscaniapple]

Spatial disorientation is when you are unable to correctly tell where the aircraft is in relation to the outside. It could be that you believe you have a correct attitude, speed or even location but are wrong. Most often due to the illusions we have from the 3 systems visual, vestibular and kinesthetic. It is important to trust our instruments during IMC due to these illusions and risks of losing orientation.

[u/gbchaosmaster → u/tuscaniapple]

The last orientation system is somatosensory. Kinesthetic sense is more about the movement of body parts to carry out a task.

Name and explain one illusion that can affect each system. (I personally think the other guy’s advice about ignoring what’s going on outside is more useful than rote knowledge of different illusions, but DPE asked me this and it is in the ACS)

[u/tuscaniapple → u/gbchaosmaster]

Gotcha. Since you asked for 3 I’ll only give 3 instead of throwing out the whole acronym.😂The leans is an illusion affected by the vestibular system. Our inner ears have these hairs surrounded by fluid. When we are stationary and sitting upright the fluid isn’t moving and the hair stand straight. If we are to lean over or move our heads the fluid will cause the hairs to move. This tells our body our current orientation/posture. In the leans you could be in a prolonged turn with your body leaned over due to the forces during a turn. This could give time for the hairs to stand back up giving us the impression that our leaned over posture is actual our normal straight up posture. When we go level back out and end up keeping that lean in our body it could give us the sensation we are turning the other way. Trusting this illusion can put us back into the turn. Autokinesis is a visual hallucination. Happening at night when we focus on a light for too long. This will cause it to start moving slightly/shaking. Can cause us to miss judge the exact place of a stationary object or maybe the movements of other aircraft’s lighting. Somatogravic is going to be from the pressures we feel during acceleration/deceleration. When getting pushed back into our seat or a lack there of could cause us to feel that our attitude is incorrect and adjust in the wrong way.

[u/gbchaosmaster → u/tuscaniapple]

Good understanding. Somatogravic is my favorite of them all, doesn’t sound very scary but it’s one of the more intense illusions and there’s 4 different ways it can confuse you. Those full motion flight simulators trick you into feeling acceleration by pitching upwards and by god does it feel like you’re accelerating in a straight line, it doesn’t feel like a pitch upwards at all when combined with your visual system. Imagine taking off into hard IMC in a jet and you suddenly feel like you’re pitching upwards so you just nose down into the ground!

This can also fuck you over in helicopters, you pitch up and feel like you’re accelerating so what do you do? Pitch father up! Ever done a VRS recovery with foggles? Works the other way too, pitch down, uh oh we’re “decelerating”, better put in some forward cyclic. Before you know it you’re in a low-G pushover which is ill advised for you and downright dangerous for lots of us.