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Instrument Approach Procedures


BigTex

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I've ready my Pelican's Perch and that doesn't make sense to me, but perhaps there's something I don't know. Is that a typo? If not, how is 18" in a turbo different than 18" in a NA? I know I could get high enough where my J won't produce 18" of MP and your turbo can still make near 100% power, but down low if the throttle is pulled back, isn't 18" the same regardless of the induction system?

Yes you are right about 18" - 18" MP is a measured 18", so the pressure in the manifold is the same regardless of the engine it is on. However your NA and my turbo have different compression ratios. The compression ratio on an IO360 is 8.7:1 I believe, and on my TSIO360 it is 7.5:1. An NA engine takes that 18", stuffs it in a cylinder, and multiplies it by 8.7. Mine does the same thing but muliplies it by 7.5 . Thus, my engine makes less power at 18" MP than an IO360 at the same MP. My engine makes up for this by being able to stuff more air into the manifold to begin with. So in terms of %BHP produced, my turbo engine's 18" probably falls in the range of 15-17" in an IO360. This is not an exact explanation of what is happening, but is close enough to give you the idea. There is more good stuff in Pelican's Perch on this, there is an article called something like "Manifold Pressure Sucks" which you might read if you haven't. 18" is actually vacuum, it is less than ambient pressure unless you are really high up where there is not much ambient pressure. It is certainly less than sea level ambient.

The other related issue with the TSIO360 in the 231, although not directly related to your question, is that in order to be able to cool the engine at high power settings the mixture needs to be set up quite rich, in fact, it goes quite high at or near 100% BHP, it should be 22-24.5 gph, which is nearly double what I would see at cruise. This means that the mixture is set rich across the entire spectrum of operations, at least in the 231, so if I go to 18" I also need to lean the engine out quite a bit or it will "burble" - sort of sputter and miss. It is not in danger of quitting in a descent because the descent itself is helping to drive the prop and engine, but it is too rich, so I need to lean where an NA engine probably does not need to. So I tend to favor stabilized approaches where I can put in a little bit of power, probably 20" or better, which in turn lets me leave the engine full rich and thus set up for a go around/missed approach if necessary.

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I used to start a timer only if there was no other way of identifying the missed approach point. With geo ref approach plates, garmin ifr gps etc, there is no real need to time at all any more.

Agreed, no need to time IF the MAP can be identified by on board nav equipment required for the approach.

BUT it is neither wise nor legal to rely on a georeferenced plate on an iPad to ID the MAP.

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Agreed, no need to time IF the MAP can be identified by on board nav equipment required for the approach.

BUT it is neither wise nor legal to rely on a georeferenced plate on an iPad to ID the MAP.

Yeah I have had foreflight crash on numerous occasions, so you are right.

I am thinking of a backup tablet with some free chart software or just view the free app charts that the faa puts out. Foreflight on a backup ipad would require a full subscription

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I think WingX can be put on multiple devices with only one subscription. I'll have to check with other devices at home to prove this theory...

This would be helpful if you have another idevice. Phone, pad, pod.

Still not primary nav, but solves any reliability/crash/battery issues....

Iphone4S is selling for $100

Iphone4 is selling for $1

At the store near me...

Best regards,

-a-

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Guess flap speed changed between 65 and 70! My Vfe is 125 mph, gear is 120. She handles pretty well at 90 knots/105 mph with approach flaps down, ~18"/2300 to stay level, drop the gear 1½ dots high and be on-slope by the time it centers.

105 with flaps up is a little less comfortable for me, but you are probably there in the pattern when VFR.

The day ATC asks me to maintain 160 knots is the day I will have no choice but answer "unable!" I have, though, been asked to reduce speed for traffic; more often, going into Class C, they will ask me to keep my speed up. That happened on my Instrument checkride as I was coming in on ILS, 8-9 miles out at 90 knots. I asked the DPE if I should speed up, he said something like "Sure, let's see what you can do." Flaps up, throttle forward, and down the glideslope at 140 mph; the difficult part was slowing back down to Vfe and not blowing the approach, but managed a nice touch-n-go, shot the missed and started on the next approach.

yeah, my flap speed is 85 knots. I fudge a little with 1 notch at 90. I was wondering if any structural changes were made when they increased flap speed or if they simply changed the rating.

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If there is a time on the plate you should always start the timer. It is there as a backup in case your primary means of determining the MAP goes belly up during the approach. I just did one last weekend where the primary received did not get a glideslope signal for who knows what reason. We did not have the secondary system set up, so had to go missed for real in heavy IMC. We got it the second time.

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No, you can have multiple devices on a single subscription with Foreflight. I share the subscription between my iPad and my iPhone.

Yes you can use the same subscription on the iphone.

I dont have an iphone, and I cannot have the same subscription running on another ipad.

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I have two iPads, a 1 and a 3. I use the 3 regularly and keep the 1 in my flight bag for a backup. They both operate on one subscription, including the 28 day downloads and georeferencing.

Not sure how you managed that unless you got lucky with a software fluke or they changed the usage terms after you bought your subscription, but current subscription rules specify that one subscription can be run on one ipad or one ipod touch or one iphone

http://www.foreflight.com/support/subscription

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Yeah I have had foreflight crash on numerous occasions, so you are right.

I am thinking of a backup tablet with some free chart software or just view the free app charts that the faa puts out. Foreflight on a backup ipad would require a full subscription

When shooting a GPS approach I have the panel mounted GPS guiding my approach. I have an I-fly 720 with the plate displayed as a backup and I have the paper plate in front of me as my primary. Unless I get an unexpected gust of wind in the cockpit the paper plate does not fail, crash or run out of power. This is the same for an ILS, LOC and VOR approaches. I download and keep paper copies of the approach plates for my departure, destination and alternate and one or two other close by alternates. I keep the full book of plates for the areas I regularly fly though they are not always the latest. However, I do have the I-fly with the latest just in case I need to go somewhere totally unexpected. I can then quickly cross it against the paper copy I have.

If all else fails you can still request no gyro ASR approach if you are close enough to an airport that has one.

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I just passed my instrument check ride in July. I did do a lot of training getting my settings and speeds set. The philosophy I used was to have everything slowed down and gear down by the FAF. That made it easy to keep the needles centered and not be too busy making additional adjustments. Ray

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When shooting a GPS approach I have the panel mounted GPS guiding my approach. I have an I-fly 720 with the plate displayed as a backup and I have the paper plate in front of me as my primary. Unless I get an unexpected gust of wind in the cockpit the paper plate does not fail, crash or run out of power. This is the same for an ILS, LOC and VOR approaches. I download and keep paper copies of the approach plates for my departure, destination and alternate and one or two other close by alternates. I keep the full book of plates for the areas I regularly fly though they are not always the latest. However, I do have the I-fly with the latest just in case I need to go somewhere totally unexpected. I can then quickly cross it against the paper copy I have.

If all else fails you can still request no gyro ASR approach if you are close enough to an airport that has one.

Agreed but paper plates are not geo-referenced :)

Hence the backup electronic gizmo

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  • 1 month later...

One last bump on this thread... For those that have a manual gear, what's your procedure for gear retraction when executing a missed approach? I'm finding it pretty challenging to get the gear up due to the approach speed I'm flying (90kts). After shooting 3-4 missed approaches, my right arm feels like I've just left the gym! Anyone with some techniques and/or suggestions would be appreciated!

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Gary:

I don't know why your J-bar is giving you such trouble. I am not certain it should. Mine works easily and does not require any real effort at all.

On go-round, throttle, trim for the climb, gear up, flaps up on reaching 1000' AGL,

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I suspect my problem is that after powering up and starting my clean up procedure I'm already at too high an airspeed to easily raise the gear. I'll tweak my procedure to let my speed bleed off some after starting my positive climb before raising my gear.

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I'm finding it pretty challenging to get the gear up due to the approach speed I'm flying (90kts). After shooting 3-4 missed approaches, my right arm feels like I've just left the gym! Anyone with some techniques and/or suggestions would be appreciated!

One thought here that came to mind. I just purchased my M20C less than two months ago with no prior Mooney experience. Before the purchase, I was lucky to find a CFII that owned a Mooney (also an M20C) in my home field so he provided transition training. After I started flying my Mooney the first thing I noted was how much easier the J-bar in my plane worked compared to the other plane at the same speeds. After a few go around in the other Money I could definitely feel my arm working!! So obviously they were rigged differently resulting in significantly different force. I looked in my logbook and mine had been rigged no more than 5 months prior. So it could simply be you a have a little too much speed after go around, or maybe your rigging needs adjusting

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To the original poster: the person who had stated about "working out the numbers for yourself" has it right. The J & newer group has some advantages in gear, flap speeds and speed brakes. In my 75 F, if I don't get it stabilized by the FAF (I use 100 knots), I won't be able to get the gear down without blowing through the VLo on descent.

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The way you do you check ride is t the same as what you'll do in real life. How about find a power setting just above gear horn alarm that the plane will fly at between 90kts-110kts. Then at final approach drop gear and help nose it over down the glue slope pull power it 15 leave it if that's your setting. Don't be concerned about flying the perfect speed down the glide slope but do be concerned about going slower than 90kts. Any where from 110kts-90k is good. Pitch up if your low pitch down if your high. Simple. Power is a vet course adjustment. Keep it simple. DRIVE it down the glide slope. It's ok to break out at 100kts just drop flaps and throttle to idle and land. Remember keep it simple. Your not flying to minimums trying to do a short feild landing! Put take off flaps out a faf if you want but it really dosent matter, preference only.

If you go missed pitch up power up, gear up. You already have some extra energy because your approaching slightly faster and remember the power setting will let you fly level. It's not going to fall out of the air.

Just don't firewall the throttle advance it ad a decent pace.

Remember what will kill you....going below glide slope and getting slow and losing trust in your instruments, watch the AI check it against the turn coordinator if you don't believe it.

Aaron

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