Go-NoGo Fog-3

[skidoo]

As and IR student, I have been curious about how other pilots make judgments. The first two scenerios show a significant split in decisions, and I hope those threads continue to accumulate some poll statistics.

I find it very interesting that some worry about engine failure all the time, and I understand some pilots will fly in IMC entirely en-route. So, I would like to try one last related scenario.

In this scenario, you are planning a trip from KGPI to KHLN. All reporting stations (which are relatively few along any route) are reporting

10 miles visibility
2000 ft ceilings
Cloud tops are known to be above 20000 ft.
No thunderstorms, no rain, and winds are calm.

Freezing levels in the area are above 16000 ft.
You have a turbo and a service ceiling of 20000 ft.

Recognizing that as terrain varies, there can be many areas where it touches and effectively becomes fog, and you will likely be out of gliding distance from airports for some of the time, what would be your

Go-NoGo decision?

 

[Sac Arrow]

Tops over that route are around 9,000 feet. I don't have an enroute chart handy but MEA's are probably 12,000 or greater.

Hell no, I don't care what the icing report says, I don't want to be in IMC at those elevations.

Scud running is a no-go in that terrain.

 

[Ted]

The problem in general with flying IFR in Montana is the limited aircraft performance you have, combined with inhospitable terrain (plus mountain obscuration, etc.), icing...

Plus, if it's IFR, the real question is what is causing it and what's in the clouds. Scud running is a good way to end up in a CFIT NTSB report. I have only flown out across the Rockies/Tetons once. I did so in a turbo Navajo that was lightly loaded in perfect weather conditions. I would do it in the Aztec or 310 in similar, but I wouldn't want to fly any of those aircraft in IMC. Doubly so in the winter.

 

[poadeleted21]

What are the MEAs from GPI to HLN? (I fly to both often VFR) has to be 13K at least. I'm not sure how you're going to scud run with airports reporting 2K Ceilings you'll barely make it over evaro hill coming down to Missoula with that and staying legal. no way you're getting into the hole in the Mountains they call Helena on a scud run with a 2K Ceiling. Knowing that route fairly well and the terrain/wilderness that lies in between, attempting to scud run it would be about the best way I know to get your very own CFIT NTSB Report.

Just for S&Gs here's the terrain for you guys who picked scud run. I'm at 10,500 in this picture. That would be about 3K deep into the layer.

 

[Morne]

VFR flyboy here. I don't scud run in the flatlands of Ohio with a 2000' ceiling. Easy no-go decision for me.

 

[gtmule]

no way. VFR here, and I wouldn't fly (a cross country) in OVC 2000ft here on the coastal plain....

 

[ronnieh]

Skidoo, you don't say whether it is a twin engine or single. Also you do not specify VFR or IFR.
I don't fly VFR so I have no comment other than I don't think I would.
IFR in a single piston, nope
Ted, I find your post interesting. I do not know what the MEA is on the OP's stated route. I have quite a bit of time in a PA31-350. If the freezing level is above 16,000 and there is no significant precip, then I think with a functioning O2 system I would go in the Navajo. No mention of turblence, light winds. I have flown the Chieften on several occasions at 15K and it seems to do well. Plus IMO the Navajo is a pretty good plane in the ice for a piston twin. This is based on a MEA no more than 13,000. Did I miss something?

 

[Ted]

Ted, I find your post interesting. I do not know what the MEA is on the OP's stated route. I have quite a bit of time in a PA31-350. If the freezing level is above 16,000 and there is no significant precip, then I think with a functioning O2 system I would go in the Navajo. No mention of turblence, light winds. I have flown the Chieften on several occasions at 15K and it seems to do well. Plus IMO the Navajo is a pretty good plane in the ice for a piston twin. This is based on a MEA no more than 13,000. Did I miss something?

In re-reading, I think my post was unclear. In the Aztec or 310 with IMC and potential icing in those areas, it'd be a no-go. Both those planes are also naturally aspirated and, although the 310 will do 15,000 ft just fine, there is not a lot of extra room there. That is where turbos would be nice.

In the Navajo, it would be a go for me, depending on the specifics of the weather and icing, of course. I do agree, the Navajo does pretty well with icing for a piston twin. It definitely does better than the 310, although worse than the Aztec.

 

[skidoo]

Skidoo, you don't say whether it is a twin engine or single. Also you do not specify VFR or IFR.
I don't fly VFR so I have no comment other than I don't think I would.
IFR in a single piston, nope
Ted, I find your post interesting. I do not know what the MEA is on the OP's stated route. I have quite a bit of time in a PA31-350. If the freezing level is above 16,000 and there is no significant precip, then I think with a functioning O2 system I would go in the Navajo. No mention of turblence, light winds. I have flown the Chieften on several occasions at 15K and it seems to do well. Plus IMO the Navajo is a pretty good plane in the ice for a piston twin. This is based on a MEA no more than 13,000. Did I miss something?

Sorry, I am assuming a Single Turbo Piston with O2. VFR or IFR is the pilots decision. Freezing levels above 16000 are not likely here in the winter, so I am not necessarily talking about this time of year. I essentially wanted to eliminate icing as a decision factor. Perhaps I should have set it at over 20k. MEAs do look to be from 10k to 13Kft. But, Minimum terrain clearance is only 10.3K.

I am just trying to gauge how a pilot who may be comfortable flying long distance in IMC and not necessarily knowing that a particular area en-route has become fogged in, yet that same pilot may not fly over a wide area of fog in VMC on top due to the fear of some sort of emergency. Perhaps I am not presenting these scenarios well, but it is showing some differences in pilot perception and judgment.

 

[Ted]

I am just trying to gauge how a pilot who may be comfortable flying long distance in IMC and not necessarily knowing that a particular area en-route has become fogged in, yet that same pilot may not fly over a wide area of fog in VMC on top due to the fear of some sort of emergency. Perhaps I am not presenting these scenarios well, but it is showing some differences in pilot perception and judgment.

A lot of it just comes down to personal comfort level. We all have things that we like and things that we don't like. Personally, I have no issues shooting an approach down to minimums. However, I do have an issue with having to divert with a plane load of dogs and spend the time, money, and hassle that comes with a diversion. Therefore, I don't want to fly when it's close to minimums, but have no problem flying in solid IMC for hours to get there.

When you're talking about the mountains out west, you can have significant weather phenomena with fewer options than you'd have in the plains and further east. Personally, I haven't flown out there extensively, and I would need to enter the waters more gently, but would still want to have a significantly capable machine to do so comfortably when it comes to IFR flight out there and the associated risks.

 

[ronnieh]

Can't add anthing to what Ted said in his last two posts.

 

[Everskyward]

I agree that it's all about personal comfort level and also about what you have done a lot as opposed to not so much. Back in the day I would much rather have flown over mountains and valley fog in a single engine piston than fly an approach to minimums but I rarely got a chance to fly real approaches and I flew over and in the mountains frequently. FWIW I've tried to climb VFR over the clouds westbound from Denver in a turbocharged piston single then realized that the tops were above 18,000. I air filed then realized that it was a struggle for the airplane to stay on top as they seemed to be rising. I didn't want to go into the clouds because I knew by then that's where the most icing is, right at the tops. Then there's another time when I climbed out IFR thinking that the tops were only about 10,000 since that's what was reported but I didn't think about the fact that the tops might be higher to the west. When I started picking up ice and I was nowhere near the top I realized that wasn't such a bright idea and turned around. After these instances I was more cautious.

 

[ronnieh]

Yes piston engine(s) and ice is not the best mix. You have a little more wiggle room in the eastern half of the US. For me if I am flying in the western mountains I want two fans and I want to be burning kerosene.
In the case of the Navajo I was discussing with Ted it does pretty good but, you need to figure in single engine service ceiling. This is where the Navajo will bite you. The people I fly for had the nicest Colemill Cheiften around. However they wanted to fly out west and in fact have land in Wyoming. The single engine service ceiling (and the speed or lack of) convinced them they needed a little more plane. IFR in the western mountains in a single piston just does not work for me. Turbo piston twin with FIKI is about the minimum equipment for me. To each their own.

 

[Ted]

Yes piston engine(s) and ice is not the best mix. You have a little more wiggle room in the eastern half of the US. For me if I am flying in the western mountains I want two fans and I want to be burning kerosene.

This is a good synopsis. There are a few exceptions, such as the RAM T310R that has performance similar to a lower end turbine twin. But on the whole, you want to be in a turbine. And then you get into the same single vs. twin debate, which Ronnie and I agree on.

In the case of the Navajo I was discussing with Ted it does pretty good but, you need to figure in single engine service ceiling. This is where the Navajo will bite you. The people I fly for had the nicest Colemill Cheiften around. However they wanted to fly out west and in fact have land in Wyoming. The single engine service ceiling (and the speed or lack of) convinced them they needed a little more plane. IFR in the western mountains in a single piston just does not work for me. Turbo piston twin with FIKI is about the minimum equipment for me. To each their own.

I'd agree with this overall, but as you pointed out the catch is the single engine service ceiling. So if I were flying out there regularly, turbo piston twin FIKI would be minimum, but it'd have to be a higher performing than stock variant. Too bad I can't do the Riley Rocket conversion in the 310 and have the 350 HP Navajo engines on it...

 

[ronnieh]

That wopuld be a honking 310!

 

[Ted]

That wopuld be a honking 310!

With the Colemill Executive 600 conversion on the one I fly, it's no slouch. But it comes with the obvious naturally aspirated limitations. Wayne has pointed out that I'm probably better off keeping it N/A, which I agree with. But it's fun to dream...