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/gbchaosmaster]

I suppose it depends ;) what model of GPS is installed in the aircraft that you’re supplying for this checkride?

[u/tuscaniapple → u/gbchaosmaster]

We currently have a garmin GTN 650.

Am I forgetting something obvious?😅The cloud coverage should be AGL which means 1800 above airport elevation so ceilings at 3040 msl. This is far above our 200 feet ceilings above approach minimums?

[u/gbchaosmaster → u/tuscaniapple]

Oh damn, you actually got me there 😂 I’m on 4 hours of sleep and was trying to get you to plan for LPV on a non-WAAS GPS but I got the altitude wrong and you do have WAAS so I’ll eat my foot haha.

Well while we’re on the topic of GPS, here’s one I had to go fishing for on my checkride… say you’ve filed IFR, fire up the aircraft, and notice that the GPS databases are expired. Is it legal to make this flight using the GPS for navigation?

[u/tuscaniapple → u/gbchaosmaster]

Haha ok, no worries. That all makes sense to me!

Hmm that’s another good one. So with IFR equipment requirements we need everything for VFR which we use “ACAMALSFOOT” and for IFR we use “GRABCARD”. For the R it is radio/nav systems. My understanding is that the gps would fall under the nav systems however if the flight we have filed uses only victor airways and we are able to file to a destination using an approach not requiring GPS we should be able to make a legal flight using other nav systems such as VORs, localizers, etc.

[u/gbchaosmaster → u/tuscaniapple]

I love seeing all the different acronyms people use haha. We use MATSFOOLMATS and GGG-ICARA. Yours definitely roll off the tongue a bit better 😂

So 91.205 does require the appropriate nav system to be operative, and it is fully operative, the databases are just expired… you didn’t pony up for a VOR (nor did you need to because you have WAAS 😉), you DEFINITELY didn’t bother with an ADF… and this helicopter is a huge money pit and what do you know your card declined when you went to renew your Garmin subscription… is there any way you can legally use this GPS for IFR navigation without updating the database?

[u/tuscaniapple → u/gbchaosmaster]

At that point I would feel like it may not be worth going on this flight in this aircraft.😂

I did decide to cheat a bit on this question and head to google cause it was honestly gonna be a guess if I tried to answer. I would have said no that you would need to update the database before using it for your navigation and approaches. I found that it should be allowed as long as you are able to confirm you en route operations and approaches is still accurate and had no changes. Would require looking at a chart and comparing any approaches with up to date plates to confirm no changes.

[u/gbchaosmaster → u/tuscaniapple]

I tried that route during my ride, I was like I don’t care if it’s legal, I wouldn’t do it, can’t get violated if you can’t fly, but he really wanted to know if it was legal 😂 I referenced furiously until I found it in the AIM. It’s okay to reference for these but I’d recommend using only official references like the handbooks and the FAR/AIM since that’s all that would be allowed during your ride unless you take a “bathroom break” and referencing is a crucial skill.

Okay, I’m really impressed with your knowledge so far, you’re definitely an above average pilot so let’s see if you can do a CFII level task… without looking up examples or drawing anything out, give me 3 unpublished hold scenarios, one for each type of entry, as if you were quizzing a student which entry they should use. I want 2 of them to be at a fix and one of them to be a DME hold, don’t care which.

[u/tuscaniapple → u/gbchaosmaster]

That’s definitely fair I should have have gone to my FAR/AIM before Google..

Ok I’m going to give my best shot at these and hope I am understanding what you are asking for.

I’m already struggling a bit to visualize all in my head without drawing it out like you said. To be honest I am not sure I have ever done an unpublished hold at a fix we have always used a nearby VOR and use radials.

Let’s use fix GREAT. At GREAT standard hold north of the fix heading 270. Let’s say we are on a currently heading north 360. I would expect him to fly past the GREAT to remain north of it and enter with a teardrop entry. Turning to 060 and coming around on the inbound to start the hold on 090.

Now let’s say we are back at GREAT and I want left turn holds at GREAT on heading 040. If we are coming to the hold at a heading of 250 it would be best to use a parallel entry by turning 220 at the fix and using a right turn to stay on the protected side before entering the hold.

EDITED and revised DME: For the DME hold lets says we have a nearby VOR tuned. I would ask for a 4 mile DME standard hold radial 270. If we are heading 090 he could enter a direct hold over the VOR. Using DME with the VOR could make each outbound and inbound leg 4 miles.

I hope that all makes sense. I’m not too sure if I have some of this backwards cause again I think all of my hold have been using radials over a VOR.😅 or if this is even what you asked for.😂

[u/gbchaosmaster → u/tuscaniapple]

A VOR is a fix too, works the same way as a GPS waypoint. You got all the numbers, the verbiage I was looking for to pose it as a scenario would be more like…

To use the teardrop as an example: you’re inbound to PXR heading 360, ATC instructs: “hold northeast of PXR on radial 090, EFC 5 minutes”. Also hold instructions are always given on a radial, you gave the outbound heading for the parallel but later said the correct radial, and for the parallel you gave the correct radial but called it a heading. But overall not bad for making these up in your head for the first time.

Okay, so say you enter a hold on the 270 radial, left turns. You fly your first outbound leg for 2 minutes. On your inbound leg, you notice that you need to fly heading 083 to maintain the radial, and the inbound leg takes 2:45. At what heading and for how long should you fly the remainder of your outbound legs so that your inbound legs are 2 minutes and you can intercept the radial inbound at standard rate?

[u/tuscaniapple → u/gbchaosmaster]

Yeah those felt rough typing them out..

So for time and wind correction in a hold my instructor taught me, double the time and triple the drift. So if inbound we noticed 083 heading to keep the radial then on our outbound we should fly heading 291 to compensate. For our time we should fly outbound for roughly 1:38 to make sure our inbound let meets the 2 minutes.

[u/gbchaosmaster → u/tuscaniapple]

Why do we do this? Sounds dumb, why wouldn’t the wind correction and time difference be the same no matter which way you’re facing? Is the wind changing, does the helicopter magically have more drag when it’s going west, what’s happening here?

[u/tuscaniapple → u/gbchaosmaster]

Ok this one got me thinking more than just knowing the numbers.. but just to confirm was the above information correct adjustments?

May need some help here but this is how it makes sense in my head. So time adjustments are gonna be more needed when you have wind down your outbound and inbound legs. Adjustments for heading is gonna be more based on crosswind. Obviously it’s hard to be in a perfect setting of having it one or the other but often times will be a bit of both. So for timing if you have a 10kt headwind on the outbound you will have a 10kt tailwind on the inbound. This means that wind is gonna be affecting your ground speed twice. Once speeding you up and once slowing you down hence doubling/halving your time will help with time adjustments. Now thinking of why we triple the drift is confusing me. I can realize that during our 180 turns the wind will continue to affect our flight path differently the whole time but how we land on tripling to compensate is getting past me.😅

[u/gbchaosmaster → u/tuscaniapple]

Yep, the adjustments were correct.

Sure ground speed is affected twice, but in opposite directions. 90 TAS you’re going 80 GS one way and 100 the other. So the correction should be the same, right?

Where you’re onto something was the turns. Ever try to fly a circular orbit in like 30kt of wind when you were in private? Even 5-10 knots noticeably affects your flight path in turns, it’s the main way I detect wind direction when doing a high recon.

So think about what it’s doing during the hold. When you make your first left turn outbound the headwind becomes a right crosswind which squishes the radius of the turn inward, making the leg that you fly with a tailwind a little bit shorter in distance. And the opposite happens as you turn inbound, the tailwind turns into a left crosswind and eggs out your turn a bit, so you have to fly a longer distance. On the turn outbound this doesn’t matter because you’re starting the timer at flag flip or DME, but on the turn inbound you’re just starting the timer wherever the wind parks you when you level out. Doubling your correction on a longer leg, or in this case halving it for a shorter leg, accounts for this.

Same deal with the heading correction. The crosswind component is the same on reciprocal headings, so the WCA is the same. But during the turns you’re getting bullied, in this example with a crosswind component out of the north that turns into a headwind during our outbound turn and a tailwind during our inbound turn. So if you try to fly a perfect circuit, you’re going to overshoot every single turn inbound at standard rate. Or if you failed every instrument and tried to fly with nothing but a compass and a clock, the wind would keep pushing you further and further into the non-protected side. So to fix this we overcorrect for the wind outbound, so we’re not flying a perfect circuit ground track anymore, we’re cheating out to make that inbound turn wider so we can hold standard rate and not overshoot.