RV-8 in actual IMC?

[mking275]

About to buy my first plane, and am about to pull the trigger on one of two RV-8's.
One is certfiied for IFR. The other is not. Neither have heated pitot, which is a personal requirment for me, and also straightforward to add before the sale.

A couple of old timer friends of the seller of the VFR bird, that have or had RV-8's, chimed in that they would not fly a RV-8 into IMC and I shouldnt bother refitting the panel for IFR.

Firstly, if I fly XC, I fly IFR. Its just safer. So, my plane is going to be equipped for IFR.

IMC is a differerent question. Brand new to the plane, I wont go into IMC. But, its summer so not a real factor. I trained for IFR in the soup in the winter in Puget Sound, and have no intention of flying without a CFII in that stuff.

My main IMC missions willl be punching through morning clouds to take off, or broken clouds at altitude because I'm on a IFR plan, and lots of regular IFR practice approaches. Real weather I have no interest in going into.

I'm interested in what other pilots have experienced in actual IMC in RV-8's. I get the idea of a light weight nimble plane being easy to get tossed around in turbulance. So, turbulance and icing conditions are no fly zones, but to me thats specific weather conditions to avoid, not a blanket no IMC rule as they seem to be suggesting. However... they are old timers, and still flying, so, I'm listening. Anything unique or unusual I should be aware of?

 

[Richard Connell]

I’m not sure how it can be certified for IFR without a heated pitot?

I flew my RV7 in IMC plenty over the years before I sold it and do the same with my 10.
I think you’ll find plenty of people fly RVs in actual WX, they’ll just all have different personal tolerances for ceilings, icing, turbulence etc.

For me I’m pretty conservative. Don’t go anywhere near the FZL, anywhere near TS and consider the autopilot to be mandatory.
Did my rating in the 7 by hand. It’s pretty sporty and requires plenty of attention hand flying in IMC - but plenty have done it.

Good luck.

 

[Taltruda]

I’m not sure how it can be certified for IFR without a heated pitot?

FAR 91.205 (d) doesn’t require heated pitot tube. Not saying it is smart, but it’s not a requirement..I believe most certified planes have a bottle in the pitot system to catch any water.. that might also be a good thing to have.

 

[Richard Connell]

I wish we had the same single page plain English regs as you guys…
Anyway. We can’t do that. And like you said, I’m not sure I would either.

 

[Foghorn]

I fly mine in IMC. It’s never crossed my mind that it’s an RV8. It flys wonderfully just like the other RVs. I would recommend an autopilot (for any IFR plane) to help carry the load. Just like any plane, backup instruments with batteries are highly recommended. I would personally install a heated pitot. I turn mine on anytime the temp is below 5C with visible moisture. I check the skew-T charts before flights to see where I can spend the most time in VFR conditions. Practice all you can. When you need it the most the autopilot will take a break.

 

[lr172]

I got my IFR ticket in the 6 and flew many flights in IMC. Everyone has an opinion, just not the same as your friend, who possibly believes that his opinion applies to all (unfortunately seems to be a human trait). While all my training was done sans AP, I would not make IMC trips without one.

Larry

 

[Carl Froehlich]

Over the last three years I’ve done at least one 5+ hour cross country in my RV-8 each month, all with a filed IFR flight plan. Perhaps 3 out of 5 flights have at least some IMC time, and 1 out of 10 flights require an approach.

I’m careful to not fly if there are thunderstorms or such that may impact the trip - I just wait for the next day.

The RV-8 is a fine IFR platform but I consider a full up certified GPS panel, with integrated weather and traffic, to be a requirement for flight. The same goes for a dual axis autopilot. I know many people have hand flown hours in IMC with just a VOR to navigate - but I’m not one of those people nor do I aspire to be one.

The RV-8 has the same dual screen SkyView panel that I had in the RV-10. The RV-10 is the Cadillac of RVs for cross country IFR flight, but the RV-8 does just fine (other than the GIB making noise about being limited to how much luggage she can bring….).

Carl

Edit - on handling turbulence. The RV-10 and the RV-8 are about the same - the 10 being a little more forgiving. Two trips ago I hit very rough turbulence over North and South Carolina in the RV-8. ADC had no options for me to avoid it and the airliners were also getting banged around. One United pilot commented that “if you can get about 30k’ it is not so bad”.

So, seat belts tight, slow down 10-20 knots and ride it out. Of note the SkyView autopilot never missed a beat.

Carl

 

[airguy]

I fly a lot of IFR and IMC in my 9A. The longer wing makes it a bit more stable than the 6/7/8 perhaps, but it still works just fine. An autopilot is a great assist, and I believe the heated pitot should be required.

 

[ronschreck]

Go for it

I flew IFR in my -8 on many occasions. Yes, an autopilot takes the stress out of it and you might want to adopt some personal minimums until you gain proficiency. I departed many aerobatic contest for home in IFR conditions while the rest stayed on the ground waiting for the weather to clear. (They never saw me thumbing my nose at them!)

While it may not be required I think a heated pitot is smart. My GRT autopilot flew coupled approaches down to the runway. All I did was play the throttle and lower flaps.

 

[Carlos151]

I built my -8 with an IFR certification from the get go not because I would be using it on a regular basis but because I might need it to get to my destination. I get plenty of IFR flying at work and I try to fly my -8 VFR but it doesn't always work out that way. Like others have mentioned, a heated pitot tube, although not required, would be a wise system to have. I have seen light rime ice start to build on the leading edges of the wings and tail surfaces but nothing that a simple altitude change couldn't correct. IMHO the -8 flies IFR no different than any other large or small aircraft. Know your aircraft and personal limitations and you can fly to your heart's content.

 

[MacCool]

I fly a lot if IFR and IMC in my 9A. The longer wing makes it a bit more stable than the 6/7/8 perhaps, but it still works just fine. An autopilot is a great assist, and I believe the heated pitot should be required.

"Conventional wisdom" here on VAF suggests that the RV-9/A's lower wing loading make for a bumpier ride. Personally, I've never seen that and I'm inclined to put it in the same category as "the RV-6/7 is "twitchier" than the RV-9/A

 

[Majorpayne317641]

I fly my RV-8a cross country frequently and in IMC. It is WAY better than any spam can in IMC. I flew a Cessna 172 glass panel spam can cross country 16 hours in hard IMC with no AP and that was a terrible experience. As soon as I got back into my airplane it was like a night and day difference not trying to row a boat around a holding entry. It’s going to get tossed around but it’s so nimble you can put it where you want it even with turbulence. A Cessna not so much.

 

[Ironflight]

One comment that not one has mentioned is that there is no real “IFR certification” for an RV, except when it comes to the xponder/pitot/static system. Other than that, the airplane must be “appropriately equipped for the flight to be flown”, which gives pilots a lot of leeway in what equipment is installed. It has already been pointed out that a heated pitot is not strictly required - smart, but not required. And what is appropriate in today’s national airspace system is not the same as it was throaty years ago - back then, there was no GPS to speak of. Today, I can’t imagine trying to fly effectively without one. Legal - yes. Smart? Probably not.

The OP mentioned that the friends of the guy with the “VFR bird” were saying they wouldn’t fly IFR in an -8….sounds just a little bit self-serving (or “friend-serving”) to me. I have flown plenty of IFR in my -8, and it is an excellent platform for such, although I’d not be happy without an autopilot. There’s a lot going on at RV speeds for a single pilot.

As for always flying IFR because it is safer, well, that’s an interesting proposition. If I have to fly across the Sierra, there re times when it is far safer to fly a winding route offer roads in case you have a problem than being cleared direct over completely unlandable terrain. I know what the OP meant ,but one size does not fit all, and the flexibility of VFR (with or without flight following) often gives one lower risk multiple options without waiting for permission….

Paul

 

[BobTurner]

+1. People tend to toss the word ‘certification’ around, but really what matters are the Op Limits. If they don’t have the ‘ifr allowed when equipped per far91.205’ statement, then you must stay vfr (ditto for night). But most have them. And yes, redundancy in instruments/power sources/heated pitot/etc is all left to you to decide. One suggestion: assuming you want a heated pitot (remember some EFIS boxes use that data to help determine attitude) I suggest looking at the thermostatically controlled ones. With the older on/off heaters you only have to land and taxi once with it on, touch the pitot and burn the skin off your finger, to make you wish for the automated (turn on and forget it) heater.
Edit: PS All RVs are less stable than, say, a 182, which means they require more work to fly in imc. It can certainly be done, but is more tiring. Which is why so many put in a 2 axis autopilot.

 

[ChiefPilot]

The whole “less stable means less suitable for IFR” argument holds no water for me. My RV is slightly more stable than the airliner I fly for work, and an inoperative autopilot is not a no-go item for that bird. Proficiency, not just currency, is the key. The RV-8 (or any of the non-LSA ones actually) are fine IFR birds when so equipped.

I wouldn’t consider a non-heated pitot. I’ve picked up ice on an IMC descent during “summer months”. It’s all about where the freezing level is and if there is visible moisture present.

And Carlos is spot on - know not only the equipment limitations but also your own.

 

[MarkW]

Bob mentions some glass using the pitot for attitude.
Other than those, why do we need a heated pitot?

I wonder which ones use the pitot for attitude. I think the G5 Garmin does but not sure about the G3X? Dynon?

I know a pitot was a necessity when we had vacuum systems but since we all have 3 or 4 GPS units with ground speed. Why?

 

[airguy]

I know a pitot was a necessity when we had vacuum systems but since we all have 3 or 4 GPS units with ground speed. Why?

You want to fly an approach to minimums without an accurate airspeed? Groundspeed only? Remember you will lose your wind vector on the fancy glass without indicated airspeed - you have no idea what the wind is doing, you're flying by ground speed only. How old is the ATIS you listened to, and how accurate is it? AOA is gone too, it relies on a comparison between the pitot and and AOA port - both are likely iced up.

You may be a braver man than I am. Just sayin'...

 

[Richard Connell]

I think (hope!) he just means the airspeed augmenting the attitude solution.

Here’s the G3X touch. I’d be confident the G5 is similar.

 

[penguin]

...

I wonder which ones use the pitot for attitude. I think the G5 Garmin does but not sure about the G3X? Dynon?

I know a pitot was a necessity when we had vacuum systems but since we all have 3 or 4 GPS units with ground speed. Why?

All the EFIS use gyros that started life as accelerometers and provide attitudes that drift quite quickly so need software to keep the attitude solution accurate. The software needs inputs from several sources to keep the output attitude numbers accurate. Gravity helps for initial alignment, heading and/or turn rate helps, air data (pitot-static input) helps and GPS position and velocity helps. In the early days (at least 15 years ago) some units struggled if the pitot iced, Dynon was one but sorted the problem quickly. It doesn't mean that if one of these inputs is missing the attitude data is immediately inaccurate. The loss of any one input shouldn't cause a huge problem. The attitude data might start to slowly become inaccurate, probably it will be 15 minutes or so before you could notice a difference if the horizon is visible out the window. The way these software algorithms work is to build a picture (model) of the characteristics of each input, and they need to be able to rely on the input, so will not accept any unknown GPS as an input.

So all the EFIS use all the inputs they can get (including pitot-static) to keep their attitude outputs as accurate as possible. A heated pitot is cheap insurance if flying IMC.

 

[Majorpayne317641]

The whole “less stable means less suitable for IFR” argument holds no water for me. My RV is slightly more stable than the airliner I fly for work, and an inoperative autopilot is not a no-go item for that bird. Proficiency, not just currency, is the key. The RV-8 (or any of the non-LSA ones actually) are fine IFR birds when so equipped.

I wouldn’t consider a non-heated pitot. I’ve picked up ice on an IMC descent during “summer months”. It’s all about where the freezing level is and if there is visible moisture present.

And Carlos is spot on - know not only the equipment limitations but also your own.

I totally agree with you on stability!!! Idk what 182 the poster before you flies but the 172 I hand flew had a terrible right bank tendency that made me want to strap a bungee cord to the yoke and it would not hold altitude in full power with a strong down draft! Anyways, Vans aircraft are great IMC platforms even when hand flown.

 

[BobTurner]

I totally agree with you on stability!!! Idk what 182 the poster before you flies but the 172 I hand flew had a terrible right bank tendency that made me want to strap a bungee cord to the yoke and it would not hold altitude in full power with a strong down draft! Anyways, Vans aircraft are great IMC platforms even when hand flown.

I was that poster, so here's my 182 story. Took a non-pilot up for a cross country flight (VMC). Once level and trimmed, I asked him if he'd like to try flying. He said yes, so I said go ahead, it's all yours, and began watching for traffic, watching the scenery, etc. After 5 minutes he's doing a great job, I thought. Then he asks, "What am I supposed to be doing?". He hadn't touched the controls. Now, I love the -10, but no matter how hard I try it won't fly straight and level for 5 minutes with no one touching the controls.

I'm also the poster that said some EFIS used airspeed data to HELP reach a long term stable solution. I believe both Garmin and Dynon can use either airspeed or gps ground speed for this, so there's only a problem if you lose both (for which the odds are higher with no pitot heat).

 

[Carlos151]

One comment that not one has mentioned is that there is no real “IFR certification” for an RV, except when it comes to the xponder/pitot/static system. Other than that, the airplane must be “appropriately equipped for the flight to be flown”, which gives pilots a lot of leeway in what equipment is installed.l

The catch is IF you want to fly your homebuilt aircraft IFR, if it's listed in your operating limitations you must comply with the minimum equipment listed in FAR 91.205. EAA has a nice article describing these requirements. So even though it's not an IFR certification, there is a MEL. Not a lot of leeway in what you're required to have for IFR flight. A transponder is actually not on the list of required equipment but good luck getting an IFR clearance without one.

"In order for the aircraft to be approved for IFR operations, the Operating Limitations must contain the following or a similarly worded statement:

“After completion of phase I flight testing, unless appropriately equipped for night and/or instrument flight in accordance with § 91.205, this aircraft is to be operated under VFR, day only.”

This is exactly what my DAR listed on my operating limitations after asking me if I had the required equipment for IFR flight.

Sorry Paul, but nowhere in § 91.205 do I see any statement that says "appropriately equipped ". I see no leeway in the required equipment list.

 

[BobTurner]

…..
Sorry Paul, but nowhere in § 91.205 do I see any statement that says "appropriately equipped ". I see no leeway in the required equipment list.

This phrase is used in 91.205 with respect to the navigation equipment required, ‘nav equipment appropriate for the flight’. But you are correct, 91.205 specifies required equipment. But it is more liberal than normally certified aircraft rules, where, for example, their type certificate requires redundant power.

 

[lr172]

Bob mentions some glass using the pitot for attitude.
Other than those, why do we need a heated pitot?

I wonder which ones use the pitot for attitude. I think the G5 Garmin does but not sure about the G3X? Dynon?

I know a pitot was a necessity when we had vacuum systems but since we all have 3 or 4 GPS units with ground speed. Why?

Well, a heated pitot is there to keep ice from preventing a loss of AS indication. That same ice is likely going to be on your wing and tail and therefore stalls become a real threat. Having a working pitot gives you a better chance of balancing stall avoidance with loosing too much altitude to avoid terrain.

Larry

 

[Dugaru]

IMC in RVs

+1. I love my -9A, but having flown both it and an equally well-rigged 182 in bouncy IMC, I conclude that a 182 is MUCH easier to control in the soup. It’s not even close. Nor is this fact at all surprising, since the 182 is a much heavier aircraft with (it seems to me) much more ponderous controls and control responses. It’s a closer question between a -9A and a 172. I’d definitely take my 9A over a steam gauge 172, as I find it much easier to hand fly with a glass panel.

I was that poster, so here's my 182 story. Took a non-pilot up for a cross country flight (VMC). Once level and trimmed, I asked him if he'd like to try flying. He said yes, so I said go ahead, it's all yours, and began watching for traffic, watching the scenery, etc. After 5 minutes he's doing a great job, I thought. Then he asks, "What am I supposed to be doing?". He hadn't touched the controls. Now, I love the -10, but no matter how hard I try it won't fly straight and level for 5 minutes with no one touching the controls.

 

[Ironflight]

The catch is IF you want to fly your homebuilt aircraft IFR, if it's listed in your operating limitations you must comply with the minimum equipment listed in FAR 91.205. EAA has a nice article describing these requirements. So even though it's not an IFR certification, there is a MEL. Not a lot of leeway in what you're required to have for IFR flight. A transponder is actually not on the list of required equipment but good luck getting an IFR clearance without one.

"In order for the aircraft to be approved for IFR operations, the Operating Limitations must contain the following or a similarly worded statement:

“After completion of phase I flight testing, unless appropriately equipped for night and/or instrument flight in accordance with § 91.205, this aircraft is to be operated under VFR, day only.”

This is exactly what my DAR listed on my operating limitations after asking me if I had the required equipment for IFR flight.

Sorry Paul, but nowhere in § 91.205 do I see any statement that says "appropriately equipped ". I see no leeway in the required equipment list.

You’re absolutely correct Karl, there is a minimum required equipment specification in 91.205 (although I don’t refer to it as an MEL, which has a different meaning in different types of aircraft operations). My reference to “Appropriately Equipped” was in terms of the navigation equipment, as Bob pointed out. Afraid I skipped over the airframe stuff there - sorry.

The required navigation equipment leads to an interesting thought experiment someone posted here years ago. Probably tongue-in-cheek, he postulated that he could file IFR with a route specifying “Radar Vectors”, and all he needed was a comm radio……. (I doubt anyone would be dumb enough to do it, but it is an interesting edge case, isn’t it?)

 

[scard]

The required navigation equipment leads to an interesting thought experiment someone posted here years ago. Probably tongue-in-cheek, he postulated that he could file IFR with a route specifying “Radar Vectors”, and all he needed was a comm radio……. (I doubt anyone would be dumb enough to do it, but it is an interesting edge case, isn’t it?)

and Paul stirs the pot of already feisty pilots, assuming that one of them will shoot some primer on a tipup canopy frame that is going onto a tailwheel airplane...

 

[ChiefPilot]

Well, a heated pitot is there to keep ice from preventing a loss of AS indication. That same ice is likely going to be on your wing and tail and therefore stalls become a real threat. Having a working pitot gives you a better chance of balancing stall avoidance with loosing too much altitude to avoid terrain.

Ice is to be avoided, for sure, but don't be overly dramatic about it. A ½" of ice on the LE of the wing or tail will not make the airplane fall out of the sky; it simply tells you that you need to find different flight conditions without delay. I think losing the pitot system on an en-route descent that encounters some ice is a much bigger threat than a stall; I mitigate that threat by turning on pitot heat when flying in visible moisture with an OAT of 10ºC or less.

This was on a descent in late May of 2022 going into KLSE. Temps on the ground were upper 70's and the ceilings were at about 9000'. The cloud tops were at about 11,500 were less than 2000' thick; breaking out on the descent I had an estimated 3/8" - ½" of ice. Ran stall tests. Stall speed at that weight with that particular ice formation increased by 3 knots. I would much prefer something like that over losing the pitot and AoA systems.

 

[Dan 57]

losing the pitot system

well... there's a certain thing that all (and I mean all, including airline ) IFR pilots have to know: PITCH/POWER values, for all common phases of flight.

I have lost airspeed twice, in icing IMC, no fretting but reverting to basics. ASI on an RV is just a nice to have thing

 

[MarkW]

To stir to pot a little further.

I understand if you lose pitot, you lose airspeed but you have ground speed.

Following Richard's flow chart, you would have to lose GPS or Magnetometer plus pitot to lose integrity of the AHRS

Yes - no?

 

[ChiefPilot]

well... there's a certain thing that all (and I mean all, including airline ) IFR pilots have to know: PITCH/POWER values, for all common phases of flight.

I have lost airspeed twice, in icing IMC, no fretting but reverting to basics. ASI on an RV is just a nice to have thing

I'd rather use judgement and experience to not lose anything, either in my RV or in the work airplane.

(and yes, various pitch/power combinations for level flight at various altitudes are detailed in a QRH procedure which nobody memorizes in its entirety but everyone has a couple of key data points ready)

 

[airguy]

+1. I love my -9A, but having flown both it and an equally well-rigged 182 in bouncy IMC, I conclude that a 182 is MUCH easier to control in the soup. It’s not even close. Nor is this fact at all surprising, since the 182 is a much heavier aircraft with (it seems to me) much more ponderous controls and control responses. It’s a closer question between a -9A and a 172. I’d definitely take my 9A over a steam gauge 172, as I find it much easier to hand fly with a glass panel.

I'll agree with you completely there, with a lot of experience in both the 172 and my 9A. The 9A is much preferable for a true IMC approach. I don't have enough time in a 182 to make a comparison there.

 

[BobTurner]

…..
The required navigation equipment leads to an interesting thought experiment someone posted here years ago. Probably tongue-in-cheek, he postulated that he could file IFR with a route specifying “Radar Vectors”, and all he needed was a comm radio……. (I doubt anyone would be dumb enough to do it, but it is an interesting edge case, isn’t it?)

Many years ago, on my ifr check ride, the examiner gave me a short flight plan to another airport, including an approach, using nothing but the ADF (enroute plus an NDB approach). About half way there, he was fidgeting, then reached over and turned off the alternator in the rented 172. The ADF needle moved 10 deg. He turned the alternator back on, the needle moved back 10 deg. I looked over at him. He shrugged his shoulders, said, ‘you know, in the old days, that’s all they had.’ That was it. I think I’d rather have had radar vectors!

 

[2theskyy]

Many years ago, on my ifr check ride, the examiner gave me a short flight plan to another airport, including an approach, using nothing but the ADF (enroute plus an NDB approach). About half way there, he was fidgeting, then reached over and turned off the alternator in the rented 172. The ADF needle moved 10 deg. He turned the alternator back on, the needle moved back 10 deg. I looked over at him. He shrugged his shoulders, said, ‘you know, in the old days, that’s all they had.’ That was it. I think I’d rather have had radar vectors!

Don’t forget the missed that includes ndb hold. Boy, have we come along way and in a positive direction. Autoland is great to get into destinations from a professional standpoint. From ndb to gps(lpv) to cat 3 autoland. Many good conversations with a multitude crew and equipment requirements. Everyone has their own personal comfort level which overrides and equipment requirements. If you want to feel more comfortable in certain situations. Go fly with someone that knows how to, has done it and doesn’t just chair fly charts and thinks they can do it because they have $100k worth of equipment in their plane that sits in the hangar.
I digress