Go/No-Go Decision Thread

[Ted]

Dave's Go/No-Go Decision thread in Hangar Talk got me thinking. When talking with Tony sometime last year he said he was of the opinion that one of the biggest things the instrument rating did was make go/no-go decisions significantly harder. Adding on things like on-board RADAR, FIKI, multi-engine, and pressurization and the decision can get more difficult still. I find hearing how others plan through their decision making to be very educational in terms of thought processes and information resources used. So, one idea I had was starting a thread for flights people made, what contributed to the go/no-go decision, resources used, and the overall outcome. I'll start.

A few weeks back I had a dog rescue scheduled from Rock Hill, SC (KUZA) to Syracuse, NY (KSYR). The flight was originally planned for Sunday. One resource I look at to get some idea a few days out of general weather conditions is the GFS MOS forecasts, found here:

http://www.nws.noaa.gov/mdl/synop/products.php

Click on the "Short-Range GFS MOS (MAV) 6-84 hours" forecast graphics, found here:

http://www.nws.noaa.gov/mdl/forecast/graphics/MAV/index.html

By Thursday night, two things on the Sunday prediction were looking pretty bad. Specifically, there were low ceilings forecasted over the entire route of flight, including at or below minimums for Williamsport. There was also a high probability of precipitation (>70%) over a good sum of the route of flight, with freezing precipitation predicted at 20-40% between Williamsport and Syracuse. Having no desire to have my plane turn into an ice cube, I decided to do the flight on Saturday instead, which looked to have high (if not unlimited) ceilings over the entire route of flight.

Saturday morning a quick check of the weather showed perfect VFR conditions forecasted for the whole route of flight. Sure enough, not a single cloud in the sky the whole flight down (which was Friday night) or back (Saturday morning). Sunday morning I woke up, went to let the dogs out, and my deck was a giant sheet of ice, as was the rest of my property. The ceilings weren't as bad as forecasted (that's pretty typical), but the freezing rain definitely was there, with icing AIRMETs surface to FL200 over the entire route of flight and Skew-Ts looking pretty nasty. I opted to not leave the house for the day.

The decision was pretty easy given the forecast for Sunday and the fact that Saturday was supposed to be so much nicer. Specifically of concern was the freezing rain. The hardest part was inconveniencing people last-minute by changing the date, specifically making it a day earlier. I think a change to my SOP for the flights now will be planning to do the flight north on a Saturday instead of Sunday, using Sunday as a backup day. It's a lot easier to push things back a day than forward. The final call is always made last-minute, but since a lot of people are involved it helps to be able to make as much of a call as you can early on.

 

[AdamZ]

Re: Gp/No-Go Decision Thread

Good thread Ted. Thanks for the Resources. I could not find them on the AWC.

 

[Ted]

Re: Gp/No-Go Decision Thread

I should credit that Tony was the one who introduced me to the MOS products. I've found them very useful, especially the thunderstorm ones in the summer. Just gives a general idea of what you might have to deal with.

I'll invite those with more/better experience than me to add new ones... that was my selfish goal.

 

[gismo]

Re: Gp/No-Go Decision Thread

Freezing rain/drizzle is one of the few things that I won't tackle deliberately (and so far, not inadvertently either). I have considered a flight or two when that was in the forecast but pilot reports and other indicators led me to believe that it wasn't real. Other than that, widespread below min cloud/visibility, reported moderate or worse ice enroute that I can't get over/under, or a solid long line of TRW pretty much complete my no-go weather list.

Even then, if the problem weather is distant and I'm OK with the idea of only getting part way towards my destination with a stop to wait for improvement I'll consider launching with a plan B or two in case the forecast is accurate. That's why I consider the go/no-go pre-flight decision to be mostly about inconvenience rather than safety with the inflight continue/divert the real weather safety issue. To me, the idea that a conservative go/no-go decision made before departing (baring unsafe conditions at departure) somehow enhances safety just doesn't make sense.

 

[Dave Siciliano]

Re: Gp/No-Go Decision Thread

I've done several write ups in the past where I kept weather and posted what I was thinking through. I'll try to do some more. One of the best things the 58P gives me is more outs: that is I can climb to FL250, have a K-ice certified plane and have on-board RADAR. That gives many more options than I had in the A-36.

Looking forward to discussions on here. One of the most animated in the past was leaving San Diego Gillespie on a low ceiling day headed East with good weather about an hour east of the airport. Perhaps we could re-visit that sometime.

Best,

Dave

 

[gismo]

Re: Gp/No-Go Decision Thread

Heading to Florida last Tuesday, the morning weather between Minneapolis and my intended fuel stop in TN varied from light snow at my home base (which ended before I got to the airport) to heavier snow across Iowa and conditions as low as 1/10 mile at 100 ft ceilings along the route and below min weather at the fuel stop. The weather was considerably better 50 nm south of the stop and the forecast called for significant improvement over the second half of the first leg. When I departed the local weather was something like 1300 broken and there were a few reports of light ice in the area and further south by the IA/MN border. I picked up one to two tenths inch of ice climbing to 7000 but was between layers at 7000. Once clear of the MSP arrival route I was allowed to climb to 11000 which put me 1000 over the highest tops. The weather at my fuel stop was "clr blo 12000" with at least 6 miles vis by the time I got there. My plan was to turn around if I couldn't get clear of the icing by the time I got to the southern border of MN, or if it began building faster than I could shed it. I had originally planned to leave on Wednesday but the forecast for that day was much worse and I had already told wife and daughter that a Tuesday departure was an alternative I needed to keep open.

Comments?

 

[Ted]

Re: Gp/No-Go Decision Thread

That's why I consider the go/no-go pre-flight decision to be mostly about inconvenience rather than safety with the inflight continue/divert the real weather safety issue. To me, the idea that a conservative go/no-go decision made before departing (baring unsafe conditions at departure) somehow enhances safety just doesn't make sense.

I agree fully, Lance. One of the issues for me is that for a lot of the trips I make the inconvenience of getting stopped part-way is huge, as I am then stuck with 15-20 dogs that I have to deal with until I can get them to their destination. I then also inconvenience the receivers, who are on a schedule for receiving the animals at a particular time (we tend to keep things pretty well on schedule for these runs). Alternately, I may have a disgruntled mother (I think I'd prefer the dogs). For the part of the flight where I'm solo and trying to get there, I don't mind being inconvenienced. Once I have my load, though, I want to have a relatively high assurance of making the trip without diversion.

When I'm either solo or with other people who understand that sometimes you don't make it to your intended destination, I'll normally embark unless there are unsafe conditions at the departure point, and then play out things as they go en-route. Those kinds of en-route choices I think would also be useful in this thread.

I've done several write ups in the past where I kept weather and posted what I was thinking through. I'll try to do some more. One of the best things the 58P gives me is more outs: that is I can climb to FL250, have a K-ice certified plane and have on-board RADAR. That gives many more options than I had in the A-36.

Yes, Dave, and your write-ups were part of what inspired this idea. I think it'd be nice to have a consolidated place where we can put some of the collective experience of the group. We have a number of people who have some very good flying experience that, even if in aircraft with greater capabilities, gives the rest of us some good food for thought.

Looking forward to discussions on here. One of the most animated in the past was leaving San Diego Gillespie on a low ceiling day headed East with good weather about an hour east of the airport. Perhaps we could re-visit that sometime.

That reminds me of a take-off I had in May. I was taking off out of BDR heading to South Carolina for a large dog run. I checked the MOS forecasts (links above) and saw some predictions of thunderstorms in the 20-30% for most of the flight once we hit Virginia. I generally find that 20-30% range is usually fairly easy to get around so long as you stay VMC and/or have on-board RADAR. Having a 496 or similar helps as well, since that helps for tactical decisions.

Anyway, the more immediate pressing issue was that when I woke up, the METARs at BDR were OVC001 with low visibility - well below minimums. However a number of the airports in New Jersey were reporting MVFR - an easy ILS in. We took off in OVC003 (right at minimums) knowing that, even if an engine failed shortly after takeoff or we had some other significant failure, we were at low enough altitudes that we could easily fly to NJ and land. Once in Virginia, there was a large thunderstorm and 45 kt headwinds to deal with. Fortunately, the thunderstorm was one big one, rather than a bunch of little scattered ones. While my copilot was napping, I asked for a vector around the storm. When my copilot woke up (just as we were passing the storm) she asked what she missed - I pointed out the left side at the large, black mass of clouds. Response: "WOW!"

 

[bbchien]

Re: Gp/No-Go Decision Thread

The MOS products have been very very good to me.......

 

[Dave Siciliano]

Re: Gp/No-Go Decision Thread

Ted: You raise the issue of departing from somewhere one can't return to. Great that you raised that. That's one thing at San Deigo, Gillespie. It's a localizer D approach; so, it may be essentially VFR and you can't get back in because of mountains. Montgomery is close by and has an ILS. So, on many occasions, I departed KSEE with another airport ILS airport tuned in if I lost an engine.

Also, there is a circling climb to get up high enough to get on RADAR. If they pick you up, you depart East, if they don't, one goes out to the coast and climbs over the VOR. Lot's of things to have tuned in and several options one must be aware of on departure, even if everything works!

Best,

Dave

 

[Ted]

Re: Gp/No-Go Decision Thread

That's an interesting point at San Diego Gillespie, Dave, especially with the mountains around. Most of the time the places I fly are pretty flat and lower altitude, so it's less of an issue. They're at least low enough that if I lose one I still have some climbing ability (although with a plane full of dogs that may prove more challenging).

The Aztec will comfortably fly along on one engine, but climbing on one is less than optimal. So, generally if taking off into IMC I try to climb around Vy through the departure procedure (single or twin), and once I know I'm above surrounding terrain, that's when I'll generally level out to a cruise climb. Of course that varies from place to place. The airport I flew into right now in Virginia (some decent terrain around for this side of the Rockies) has a GPS and a LOC approach, neither of which have very good minimums. This summer I took off out of here with it probably about OVC004 (below minimums). I'd have to head southeast towards KGSO or KINT to get a better ILS. Even if a lost an engine right after entering the muck, the departure procedure for runway 8 (which is what I always use for takeoff - there's a significant slope to the runway that makes 26 undesirable) takes you out towards the NDB, which you can do a hold around until you gain sufficient altitude to continue. It sounds generally similar to what you talk about at San Diego, except I'd likely have to fly further on one to get to an ILS.

 

[Jim Burns]

Re: Gp/No-Go Decision Thread

Lots of good stuff here: http://www.nws.noaa.gov/mdl/synop/products.php I've used the MOS text info for years on our farm, especially the short range forcasts. They also forecast exteme high/low temps. Here's an example for STE http://www.nws.noaa.gov/cgi-bin/mos/getmav.pl?sta=KSTE. I keep links to several of our nearest stations on my desktop.

 

[SCCutler]

I am generally pretty conservative - if I am headed to a destination with a non-precision approach, I don't go if I anticipate WX anywhere near minimums, and never unless I have an out to either VMC or very benign IMC. I might launch to somewhat lower forecast weather if I am arriving at a destination which (1) has a good precision approach; (2) has lots of options; and (3) is familiar to me (varying degrees of all three). Example: flying to Addison, with both ILS and GPS approaches, and rock-solid alternates like DAL (Love Field), HQZ (Mesquite) and TKI (McKinney), all with excellent approaches.

In addition, I like to use full tanks, because around here, it's a rare thing indeed to encounter a weather pattern that does not place excellent VMC within one to two hours' flight east or west (usually west).

I generally avoid night IMC; there are exceptions, but they are just that - exceptions.

I don't launch into IMC with a lot of embedded convective activity, or PIREPs of a lot of turbulence. If I ever get XM-WX, that will *help*, but is not likely to materially change the decision process up front.

Icing's a no-go.

And (with apologies to Ed), I don't purposely launch to extended IMC if the autopilot's inop; I know, it makes me a bad pilot, but I sure like having the wing-leveler for briefing the approach, etc.

 

[Greg Bockelman]

And (with apologies to Ed), I don't purposely launch to extended IMC if the autopilot's inop; I know, it makes me a bad pilot, but I sure like having the wing-leveler for briefing the approach, etc.

Why apologize to Ed? An Autopilot is a TOOL and should be used as such.

 

[tonycondon]

i always like the go no go threads. the last few winters i posted a lot of this kind of stuff because i was hanging out at the airport a lot and flying a lot. not so much this winter so now i guess i will enjoy reading you guys' stories.

 

[Everskyward]

Icing's a no-go.

You mean you don't go when it looks like this?

 

[bbchien]

Today was a no go. After battling the snow all day yesterday, the FBO operator finally gave up.

Chronic nonsupport by the airport authority, the big 8 ton truck refused to start (GPAA does the maintenence and it's for s_it), no frikking way to get it done If I HAD TO GET OUT I could but it's just not worth powering through the snow to get to the 1" pack on the runway.

Sigh.

 

[SCCutler]

Why apologize to Ed? An Autopilot is a TOOL and should be used as such.

Agreed, but Ed is a much more confident pilot than I, especially with regard to his instrument skills (and I have no doubt that confidence is well-placed. I like George on my team, I admit (hell, I proclaim).

You mean you don't go when it looks like this?

Mari:

If it looks like that, odds are pretty good I won't even step outside the house.

 

[Everskyward]

If it looks like that, odds are pretty good I won't even step outside the house.

That was KPIA yesterday (I just figured out the irony of the identifier).

I was doing paperwork in the airplane and thought that would make a cool picture. We deiced after Allegiant and left with no problems. Big thumbs up to the crew at Byerly. They are one of the most efficient deice crews I've seen.

As far as go/no-go decisions, I look at first if it's legal then if it's safe. The reasons I can think of offhand not to go or to consider other options are; weather below minimums, runway too short for conditions, freezing rain or severe icing, no flying through thunderstorms, no braking action nil. There are other more uncommon reasons that don't come to mind right now.

 

[dmccormack]

What's dependent on this flight? (Must I go?)

I avoid launching at night over the Alleghenies unless I have full confidence in the airplane (Flown it frequently, recently). I won't do IMC SEL at night over any stretch that isn't littered with airports (pretty much everything east of here).

What can the passengers take? I'll scrub rather than causing them to hate GA flight.

 

[Dr. O]

I did a no go yesterday from Saginaw, MI (KMBS) to Valparaiso, IN (KVPZ) and back...
Your picture above is just about the reason why...

denny-o

 

[Ted]

i always like the go no go threads. the last few winters i posted a lot of this kind of stuff because i was hanging out at the airport a lot and flying a lot. not so much this winter so now i guess i will enjoy reading you guys' stories.

It seemed to me that a lot of good go/no-go stories were being told. They tend to be good reads and have useful information, so I thought it'd be good to have a more central place to find them.

 

[Ted]

What's dependent on this flight? (Must I go?)

No you don't need to go, but you know that.

What can the passengers take? I'll scrub rather than causing them to hate GA flight.

That was my exact point with the dogs. Because of the number of people involved (and the fact that I don't want to end up stranded with 15-20 dogs), it's more important that if I say I can make a flight that I be able to. For the most part, this hasn't been a problem.

 

[dmccormack]

Since my pax tend to be human family and freinds, they are able to remind me later (often much later) of any unpleasantness.

So when I take my wife flying bumps are all I care about. When we flew MGW to CSG, we took off at night rather than wait for daylight and the incoming disturbed air.

It's amazing how much more nervous I get for the sake of passengers when the flight might be uncomfortable for them (when I wouldn't have even noticed the bumps).

 

[gismo]

What's dependent on this flight? (Must I go?)

I'm curious as to how you apply the answer to that question. Some might say that if you feel compelled to fly, you should take that as a reason to NOT go unless you're talking about circumstances involving near certain death if you stay (e.g. pigmys with poison darts chasing you).

What can the passengers take? I'll scrub rather than causing them to hate GA flight.

Good plan.

 

[dmccormack]

I'm curious as to how you apply the answer to that question. Some might say that if you feel compelled to fly, you should take that as a reason to NOT go unless you're talking about circumstances involving near certain death if you stay (e.g. pigmys with poison darts chasing you).

I will probably accept more risk to get someplace than I will just to buzz around for an hour. So why I'm flying is a factor in the overall equation.

That said, I don't plan GA flights for narrow-window events ("We have to leave right after work two weeks from Friday and can't leave until 7 PM Sunday and I have to be at work Monday morning...")

So when we fly somewhere for more than a day trip, I typically schedule one more day on either end as vacation.

 

[Ted]

I will probably accept more risk to get someplace than I will just to buzz around for an hour. So why I'm flying is a factor in the overall equation.

I'd agree with this. For pleasure flights (more often to just take someone flying), I'll generally cancel if the winds are high or some other condition that won't make the people come away with a pleasant feeling on flying.

That said, I don't plan GA flights for narrow-window events ("We have to leave right after work two weeks from Friday and can't leave until 7 PM Sunday and I have to be at work Monday morning...")

So when we fly somewhere for more than a day trip, I typically schedule one more day on either end as vacation.

I always make it known that I plan for certain days to travel, but the reality of the trip may be plus or minus a day. Since getting my instrument rating, though, there have been very few trips that I have canceled due to weather, fewer still with the Aztec (there are a lot of trips that I would have had to cancel if I didn't have a FIKI bird, even though no ice was picked up.

 

[dmccormack]

I always make it known that I plan for certain days to travel, but the reality of the trip may be plus or minus a day. Since getting my instrument rating, though, there have been very few trips that I have canceled due to weather, fewer still with the Aztec (there are a lot of trips that I would have had to cancel if I didn't have a FIKI bird, even though no ice was picked up.

I'm trying to remember a flight I've cancelled, as opposed to just moved a few hours this way or that...

None..?

 

[SCCutler]

I'm trying to remember a flight I've cancelled, as opposed to just moved a few hours this way or that...

None..?

Funny, but you ring a bell with me here.

I have only had to cancel a few, and of those canceled, nearly all (in hindsight) could have been successfully completed. But, I do not regret any of the cancellations, and would typically make the same call again. It is when I start to loosen my standards that I fear I'll make really bad calls.

 

[dmccormack]

Funny, but you ring a bell with me here.

I have only had to cancel a few, and of those canceled, nearly all (in hindsight) could have been successfully completed. But, I do not regret any of the cancellations, and would typically make the same call again. It is when I start to loosen my standards that I fear I'll make really bad calls.

Yep -- better to be driving wishing I was flying....

 

[Ted]

Since a number of my flights are time-specific, moving them has frequently not been an option. Generally what stops me is also prevalent for more than a few hours, so just waiting around rarely does much.

It's a pretty rare event. I think I've only canceled 1 or 2 flights, the rest have been rescheduled (usually +/- a day), but that's also pretty rare, I can probably count the number of times on one hand.

What Spike said, though - I don't regret any changes in schedule or cancelations due to weather. Even if it was doable (which it usually was - with hindsight) it wouldn't have necessarily been a good idea.

 

[AdamB]

I ended up scrubbing a flight I was going to make today. Well actually I made the call last night.

On a whim, a local pilot friend and I decided to see about flying to Myrtle Beach, SC from the Boston, MA area for an overnight golf outing.

Planned departure was to be for today (12/29) returning tomorrow (Weds) night.

The TAFs, as of last night, were still looking a bit sketchy as to ceiling and some lingering snow showers yet to come through the area in the morning hours as this cold front passed.
This looked to last until about noon time, which was at least an hour if not 2 hours later then I wanted to depart.
Not having a FIKI bird, I was certainly concerned with freezing levels to the surface, thanks to this low pressure front that had just passed us bringing in some
Arctic air from Canada, and forecast ceilings at or slightly below what I've experienced Boston and NY to like me to fly at for IFR.

Everything I looked at for the return on Weds looked fine with high pressure moving in behind the cold front.

Of course the winds were also forecast to be fairly strong too, being the first day after the front passage.
In retrospect, looking today there were several AIRMETs for turbulence, and even a SIGMET in the NY/NJ area (directly in my route of flight) for occasional severe turbulence below 8000'.

Some of the PIREPS I captured today in re-looking at the no-go decision I made:
KMMU 7:25 AM B737 Moderate Severe 5000' to 6000' During climb
KMVY 3:00 PM 4000' C172 Moderate to Severe IMPRVG at 5000'
KBED 5:12 PM 2000' C560 Extreme 2000' to 100' Low-Level Wind Shear +12KT 500' to 100'
KBED 6:40 PM B737 Severe Low-Level Wind Shear +15KT during descent RY29 BED

Some pretty big iron reporting moderate to severe turbulence, granted all reports a bit earlier and later than my planned departure/flight time, but a general sign of the wind conditions today in the north east.
Certainly looked like it would have been an interesting first couple of hours of flight had I chosen to go.

A couple of other factors in the decision were the fact that I came down with another head cold the day before xmas. It has steadily improved ever since, with yesterday being the first day I didn't have any nasal congestion. I'm feeling a bit better today, with a slight cough still lingering, but certainly not 100%.
That, and the fact that even as far south as SC is struggling to get to 50° F surface temps for daily highs, just didn't seem to make for an enjoyable time.

So instead I'll be enjoying a local flight tomorrow for lunch with some local pilots, and saving the SC trip for another time.

 

[Ted]

Great write-up, Adam, that's exactly the sort of thing I was hoping people would post that gives some good info.

Your bird doesn't have FIKI, but it does have O2 and a turbo. Did or would that play into your decision at all? Just wondering because I've frequently adjusted my altitude to get a smoother ride (usually climbing). The other question there is that depending on the tops, if you could have gotten above it you could have probably stayed out of icing territory.

That makes me think of when I flew the Mooney out to Iowa for Tony's graduation party last year. No FIKI, no turbo, no O2. When I took off out of Williamsport it was reporting BKN020 or something of that sort, but there were lots of holes going above the clouds. I took advantage of one of them and climbed up to 8500, which got me a 45 kt headwind (ouch...) but also put me on top of what was a solid cloud layer as I headed west over PA, and then turn into clear skies over Ohio. The area forecasts were predicting tops of around 10k for the area (I have frequently observed them to be conservative in that regard - not necessarily a bad thing).

The reason I decided to go ahead with that flight was that as I headed west (well before my first fuel stop) the conditions were supposed to improve and I'd be able to land at my destination. If my engine had quit over Pennsylvania I would've ended up having to descend through an icing cloud layer (not fun), but I considered the probability of that pretty low, and brought my instrument charts along just in case. Sure enough, as I hit the Ohio border the skies cleared up. I likely would not have made the trip had the forecasted conditions be the opposite - i.e. easy at departure and potentially not doable at destination, or else potentially modified my route to make an earlier fuel stop right before the cloud layer, taken back off and flown above it, and then made another fuel stop after it.

 

[AdamB]

I'd have to say that the O2 and Turbo certainly give me options if the opportunity presents itself. I have lots of room to climb higher, if need be, assuming I'm comfortable
that the tops are below 25,000' along my entire route after my weather briefing.
Still, without FIKI, I'd probably wait until I saw the latest updates on cloud cover and any PIREPs of tops, to validate the area forecast, skew-T's, cloud top temperatures, etc... that I look at right before departure.
That way I'd have a better understanding of the likelyhood of any holes to be able to get up through or what the thickness of the layer I'm dealing with is.

I didn't really get that far with this trip, as I canceled the night before, so I don't think it played a role in my thinking this time.

This trip sounds a lot like yours where the area I was headed to was CAUV well before my first planned (backup) fuel stop (I was going to try direct and divert if needed for fuel).

This time of year I find myself tending to try to stay VMC below an overcast layer, if at all possible, when icing is even a little bit of a concern. Maybe this is somewhat based on my experience level and the newness of having a plane that actually can climb at > 1000'/min up to the mid teens. That capability certainly could minimize the risk/exposure of blasting through thin stratus layers (say 1000' or less), but I've been hesitant to do it thus far.

Good thread! I've always enjoyed reading some of these, and as the season goes on,
I'll try to capture some graphics through the process to better illustrate what the conditions looked like in making the decision.
The learning continues...

 

[Ted]

This time of year I find myself tending to try to stay VMC below an overcast layer, if at all possible, when icing is even a little bit of a concern. Maybe this is somewhat based on my experience level and the newness of having a plane that actually can climb at > 1000'/min up to the mid teens. That capability certainly could minimize the risk/exposure of blasting through thin stratus layers (say 1000' or less), but I've been hesitant to do it thus far.

I think that makes sense to do most of the time. The problem with going VFR over the top is that you have to get back down below it. Potentially picking up a bit of ice in the teens is one thing if the freezing level is still 9000 MSL, but it's another thing when it's freezing down to the surface. All about what level of risk you're willing to take and how much you trust your engine.

The learning continues...

It never stops!

 

[bbchien]

Funny, but you ring a bell with me here.

I have only had to cancel a few, and of those canceled, nearly all (in hindsight) could have been successfully completed. But, I do not regret any of the cancellations, and would typically make the same call again. It is when I start to loosen my standards that I fear I'll make really bad calls.

See. That is called airman judgement. :smile:


"A say, I say, pay attention, son...."

 

[gismo]

This time of year I find myself tending to try to stay VMC below an overcast layer, if at all possible, when icing is even a little bit of a concern. Maybe this is somewhat based on my experience level and the newness of having a plane that actually can climb at > 1000'/min up to the mid teens. That capability certainly could minimize the risk/exposure of blasting through thin stratus layers (say 1000' or less), but I've been hesitant to do it thus far.

I think you're wise to be "hesitant" since climb is the first thing to erode when ice contaminates the wings and I suspect that your wings are particularly susceptible to contamination induced loss of lift. It would be enlightening to find out what happens to your climb after climbing through several thousand feet of moderate icing on a day when there's plenty of warm air above the ground.

OTOH, moderate ice is usually limited to a few thousand feet vertically so if you have reason to believe that you wouldn't accumulate enough ice in four to five minutes (e.g. multiple recent PIREPS in the area indicating only light icing and/or that the icing is limited to a few thousand feet) I'd certainly be tempted to climb through to an ice free altitude in a turbocharged airplane without FIKI. That said I have experienced the accumulation of 2+ inches of ice on unprotected surfaces within five minutes in what was predicted to be light to moderate.

 

[jesse]

Don't be shy to ask the controller to check with another aircraft to see what the tops are. Often there is one pretty close to you that'll gladly tell you what they see for tops and if they experienced any ice. Checking PIREPS doesn't always provide you with all the info there is to have as not every pilot will provide an official PIREP. Once they hear you inquire though they'll usually speak up.

I try to look at the potential for ice and whether or not people are actually experiencing it. If there is potential I avoid the clouds. If it seems as though no one is getting ice and I am confident I can limit my exposure I'll climb through.

 

[Ted]

Well, today's flight seems like a good one for the thread.

I had a visitor for New Years whose flight was into and out of PHL. Looking at the weather it looked like the flight would be a safe one, but it would be windy and bumpy. Last night, the TAFs were reading winds that were going to be gusting to the high 30s at PHL and low 30s at IPT on a 300-310 heading range. PHL has 26, 27L/R, and 35 to choose from, which basically meant the winds were going to be bad for all runways.

This morning a double check of the weather confirmed high winds in both locations. Although it looked like it would be IMC the whole trip, a check of icing PIREPs and Skew-Ts didn't indicate that there was an icing threat. Ceilings were high enough that should allow an easy instrument approach or else a visual. Lots of turbulence reported, but I also know how the Aztec handles turbulence (well).

The flight itself was, as expected, quite bumpy. In cruise above 4000 ft it was mostly smooth with light chop, but not bad. Winds were howling as almost a direct tailwind, with ground speeds over 200 kts the whole trip down, seeing 230 in descent. The windshield got a bit of light ice (it ices up first) so I left the pitot heat, windshield heat, and prop heat on for a good portion of the flight (most of it was in actual). No ice accumulation. Unfortunately, as typical for approach into PHL, they descend you early which meant more time in the bumpy zone. It only got bumpier as we got lower, and I got assigned an ILS 26 into PHL, which meant they vectored me further out than normal. Fortunately no holds, which I was afraid might happen.

I got switched over to tower, hearing every plane complain about wind shear and heavy turbulance. It was a rough ride on the way down, and I definitely had both of those. Winds on final as reported by tower were 310 @ 22G38, making for a significant crosswind component. Working the controls I still managed to get it on the ground pretty smoothly (and close to centerline) and taxiied off to Atlantic.

The flight home was about the same, except those massive tailwinds turned into massive headwinds, resulting in around 90 kts over the ground for most of the flight home. Clearance was to 5000 ft on departure. I had about half fuel and just me on takeoff, plus the cold day, so I kept it firewalled in the climb, getting 1500-2000 FPM climbs to try to get above the really bumpy layer as fast as possible.

Once again it was smooth for most of the flight home, although the IMC had cleared up mostly so I was above the layer. Once I was back in IMC I picked up trace ice, once again leaving the pitot heat, windshield, and prop de-ice on. At some point I turned off the prop de-ice because I wasn't seeing any accumulation on any surfaces, windshield or otherwise. On landing, I saw a little trace ice on the props that the heat would have shed. Lesson learned: leave the prop heat on if I'm leaving the windshield and pitot heat on. That should be obvious. No noticed performance degredation. Only a hair of ice on the wing and tail boots.

This is the sort of flight that could easily be a case of get-there-itis. Bad crosswinds, motivation to get to the airport (a connecting flight), general not-great weather. The reason I made the trip was that there weren't concerns for any significant icing, and the turbulence I expected to see would be managable, if not fun. The airplane was a big part of this. The Aztec handles turbulence very well. Where the Mooney would smash me around in bad turbulence (ATC once heard me say "Potomac approach, Mooney 7785 AGH!!!! mike level 5000." "Are you ok?" "Yeah, just hit a bad bump there."), the Aztec handles any turbulence I've flown through well, and the massive rudder makes for good crosswind landing characteristics. I might have considered flying in a smaller plane depending on the plane and if the winds were down the runway at both locations, but given the significant crosswind component at PHL, that was important. The de-ice equipment was important to me given the potential for icing, even though there wasn't much concern of it. I would not have made the trip in a lesser plane. I also wouldn't have made it if it was a "just for fun" trip. I also am comfortable with my plane's crosswind landing characteristics and know its capabilities. Proficiency was a big factor in the decision here. So in summary:

1) The plane I fly was appropriate for the potential weather conditions
2) I'm comfortable with its characteristics and with flying in such weather
3) I was prepared for what I was going to encounter

I wouldn't have made the flight otherwise.

 

[dkalwishky]

I haven't read the replies to this thread yet but I intend to. This is my reply to this very question.

As an instrument rated pilot myself I have found that the go/no-go decision has become much easier for me. I look at the weather and if it's at or above my minimums then I launch. In the summer time I am cognizant of thunderstorms and convective activity and in the winter ice.

When I was VFR only I had to be extra careful with the forecast, visibilities, cloud layers and whatever else was on my mind.

 

[flyingcheesehead]

As an instrument rated pilot myself I have found that the go/no-go decision has become much easier for me. I look at the weather and if it's at or above my minimums then I launch.

I dunno - I tend to choose "go" more often now that I'm instrument rated, but the question has become more complex and difficult to answer, IMHO. Usually when you're VFR, the "no-go" is a fairly easy decision to make, and if you do go, you can at least see the hazards coming. IFR, sure you can go into that cloud deck, but what about ice/TS/destination weather/etc?

Maybe the reason I think it's more complex is also that I'll fly into some serious crap. "My minimums" are the ones that are on the approach plate. If I'm not proficient enough to shoot an ILS to minimums, I'm not proficient enough to fly IFR, period. I'll also go looking for the crappiest weather around if I'm doing an IFR proficiency flight (to keep proficiency, not regain it!) so I've done a fair number of ILS's to 300 feet or less. Only had to miss for real once though.

Anyway - Now, the flight that was an obvious "no go" when VFR has a lot more questions attached. Is there icing forecast? Is there a chance that there'll be icing that's not forecast? If I do hit icing, do I have enough outs to be safe? (Repeat all of the above questions for TS.) What's my destination weather like? Do I need an alternate? What's the alternate's weather like? Where's the closest VFR weather, and is it within my range if necessary? Am I going to be able to get on top of the weather enroute, or will I be in the soup the whole time? How much sleep did I get last night? To me, it's a much more complex decision, really a series of decisions all based on quite a large number of factors. Often it's still an easy one - +FZRA is a pretty automatic no-go; punching up through a thin layer to get on top is usually a go - But the gray area in between gets a lot more interesting IFR, IMHO.