Best altitude for thunderstorm line penetration.
 

If you have to penetrate a line of thunderstorms and you do not have oxygen and are not pressurized what altitude is best.

There are no "best altitudes" to tangle with CBs, there are just bad and worse! however having said this we went down as low as safe when going through the Inter Tropical Front North of Australia in DC4s and 3s, all of which leak like a bloody British sports car!

“There is no reason to fly through a thunderstorm in peacetime.” – Sign over squadron ops desk at Davis-Monthan AFB, AZ.

I realize you did not say "penetrate a thunderstorm" but referred to a line but I thought the sentiment expressed has a great deal of truth to it.

There will be if your job is ferrying aircraft internationally for example.

Suppose you are over an ocean beyond your point of no return which is a common scenario.

Then you've done a poor job of flight planning. If however you find yourself in this situation, start a deviation around the line as soon as possible. If you deviate soon enough you should be able to get around the line without burning too much fuel.

By the way, I realize you are trolling, but young pilots may read this thread and think it is ok to fly through a thunderstorm. DON'T DO IT.

I am not trolling I am disusing weather related problems that can occur during long distance flights, should one find a situation where you have to fly through a line of thunderstorms in a unpressurized airplane you will have to decide at what altitude you will fly through the system.

Telling young pilots " Don't do it " is fine, however they may one day be faced with such a decision.......so I see no problem discussing such an event.
One route where flight planning weather wise can be very difficult due to the distance involved is West Africa to South America, the ITCZ can be many hours from the departure airport and the weather at the ITCZ can change very rapidly.

So what do you do if you find the frontal zone very active and you are past your point of no return?

So how do you determine if you can get around the front if you do not have weather radar and you have hundreds of miles to go to reach land?

I realize most flying today is done at high altitude in modern well equipped jets.....

....however there are still occasions where older aircraft are ferried trans oceanic and sometimes penetration of vast very active frontal systems can not be avoided.

....another wicked weather factory is in the Amazon region where the ITCZ can change very fast and once again weather information can be sketchy at times.

Anyhow, trolling was not my intention, I see nothing wrong with discussing what can go wrong and what one can do to mitigate the danger.

And not everything that is red or magenta on the weather radar means turbulence.
Can you visually assess the thunderstorms in your scenario here?

I'm flying between 4-5*S at the moment. Thunderstorms are a common occurrence. Not nice when they like to form blocking the "freeway" between two 16,000ft mountain ranges.

Thankfully, oxygen is available to us.

Sometimes it is very difficult to see the CB's visually, however at night you can sure see the lightening flashes and that gives you some help trying to stay out of the worst of it, fortunately you fly through most cells in a relatively short time and if all else fails you just slow down and do your best to keep the airplane under control and hope for the best.

For sure it is worse in the mountainous country than over the ocean especially when it comes to what height above ground you can fly.

There are still a lot of airplanes that are flown in these conditions even in this jet age.......Twin Otters are frequently ferried over very long distances and encounter these weather problems and God knows the Twin Otter is no jet. :E

Minimum enroute -500 feet. Or so I've been told. ;)

Deviation unpressurized
 

With no wx radar or a old one and unpressurized, just fly as far as practicable away from the lightening on the upwind side and stay as low as possible for warmest temperature, ideally well below the freezing level, so you wont get hit by the biggest chunks of ice.
I flew twin otter and embraer 110 through some nasty weather at day and night, summer and winter, and im still alive :) during winter its is more dangerous as u can go through severe icing and be covered with ice in a matter of just a few seconds, your only option is at the first sign of icing do a 180 back, I once experience severe icing on a 12 DME arc at night SA and FT were all ok no icing or wx forecast at the airport, but I went through a cloud at night before intercepting the localizer, it last for only a few seconds and I was covered in ice so bad that I decided to continue as a 180 would have brought me down without a doubt, I exited the cloud after a few secs and was going down the ils with max continuous power yes MCT, and I touched down at MCT, that happened once in my 27 years of flying. There was nothing else to be done in that situation, I was just lucky enough for the cloud to be just big enough to keep me flying. At night with no wx radar during winter and no lightening from the cloud is the most dangerous situation. That happened in the north of Canada. of course you will say what? no wx radar, consider this I had a wx radar but lets say it was not picking up anything as the old technology was not as good as today. If u want to stay alive, just don't continue the flight path if you have any doubt or questions in your head, as you pick up experience you will learn how to evaluate the power of mother nature in any given situation more accurately. Stay safe

Pet peeve. Lightning doesn't have an "e" in it. Lightening is just something that pilots should do to maximize their chances at the bar on a Friday night. :}

In my PA31 days, I never had to penetrate a solid line of CBs, but I was fortunate to fly in an area where weather information wasn't scarce so flight planning to avoid it was relatively straight forward. I only recall the advice I was given by my more experienced colleagues in my early days. If you have to go through, fly as low as you safely can (respecting MEA); do your best to remain visual as along as possible; and try to pass the worst areas of precipitation and lightning on the upwind side.

My pet peeve is when someone has to make sure to pull the ITCZ out their butt every time thunderstorms are mentioned.

Never heard of a good altitude wrt CBs and I don't think that there is one.
Stay away from them or you'll probably die is a better motto.

My question was not how to fly through C.B.'s saudipc-9 it was what altitude would you fly at if you were forced to fly through a line of thunderstorms in frontal system that you could not get around.

I am aware it should be a rare occasion but if you are flying long ferry flights in some parts of the world sooner or later you may have to decide how you are going to fly through the front.

Flying is an activity that can sometimes become very dangerous no matter how careful you plan.

I don't know anyone who will deliberately fly into an active C.B. if they can avoid it, but there can be times when you may end up inside one no matter how hard you try and avoid doing so.

It can be done without ending up dead.

5000ft seems to be the number that the hurricane "penetrators" do it at off of the states.

I'm gonna say you'll have a hard time maintaining any particular altitude if you're dead set on flying through thunderstorms. Request a block and maintain level flight with your, I dunno Chuck, friggin carb heat on or your inertial separators open? Penetrate at your turbulence penetration speed at the whitest, narrowest, least puffy-looking area as far upwind as you can get. With no 02 I'd stick at 10,000 so as to, ya know, maintain the flow of oxygenated blood to your pea brain. :)

This is all assuming that for some reason prior to reaching your point of no return you had been listening out on 123.45 and 121.5 for PIREPS and canvassing other aircraft on your route of flight about conditions down route. Had you heard about developing thunderstorms a decision to turn back might be smartest.

Chuck,

I get what you were saying and I didn't say anything about penetrating a CB. There are a lot of variables that need to be looked at i.e what's the cloud base, now big are the cells, do you have a radar, how close are they to each other, are you vmc or imc etc etc. All in all I just don't believe that there is an answer to your question beyond wait for the line to pass you and then go.

saudipc-9 for sure there is no one size fits all when it comes to flying in the vicinity of thunderstorms and most flying today is done in areas of the world where there is very good weather forecasting and real time weather available.

However, there are areas around the world where low level weather forecasting and real time weather is sketchy to say the least.

Bearing in mind penetration of active fronts in the lower levels ( Below FL180 ) is a high risk part of flying for sure, so if faced with no choice but to penetrate an active frontal system the lower you can safely fly through it the better your chance of safe passage, and also once committed to flying through it try and penetrate the front at as perpendicular a track as possible to give the least time in the front.

Back before the days of GPS I was ferrying a PBY over the ocean and ran into a situation where I had to get through such a front and at the time I was flying in T effect for lower fuel burn to extend my range and found that staying at one hundred feet allowed me to pick my way through the heavier rain due to being below the cloud and also the vertical air currents get flattened out at the surface and the up and down movement of the airplane is cushioned by the descending air bursts being flattened out at the surface.

It was not pretty but considering how violent those same up and down air currents would have been a few thousand feet up it turned out to have been a smoother ride.

ONCE AGAIN!!!!

This discussion is not meant to be used as a suggestion that this type of flying is something to be treated lightly, it is meant to be a discussion on how you may mitigate risk when there is no choice but to find a way through a frontal system.

Fortunately the days of flying old low performance airplanes in remote parts of the world with ancient navigation equipment is getting to be very rare, but there was a time when that was part of being a working pilot.

Those days are gone, Chuck.

Yes they are.

But the physics of aerodynamics and meteorology remains the same, and what harm is there in discussing the subject just in case someone finds thy are faced with this problem?

There are still a few pilots ferrying low performance airplanes over long distances and the possibility of having to fly through such weather is not impossible.