Thunderstorm Avoidance
 

I'm curious...

Our FCOM is very loose with regard to severe weather avoidance. It says to avoid it, but also "avoid unnecessary diversions", that's all.

I know some carriers are rather specific about avoiding significant weather, namely thunderstorms and suchlike.

What do other operators (your company) require in your FCOM?

Ahh, "avoid". They seem to place the decision and liability on you. Avoid the yellow and don't fly into the red. Your company is not concerned with a comfortable flight, burn the fuel if you have it is the bottom line, they will not question a safe flight!

Well....if those shonky low cost bogan-carrying trashy outfits
civilled themselves up and installed a First Class section they
probably would be.

REAL airlines will avoid thunderstorms like the plague, or at
least avoid the red and magenta areas. A report with the full
reasons why one punched through a nasty movie-disrupting
latte-spilling and praline-dropping thundery is also the norm.

No one gives a crap about a fart-riddled urine-soaked airbus
if their beef jerky or instant noodles end up all over the walls
or on the floor as that's where they usually end up anyway.

I'm not so sure it's the colours that show the really nasty bits. It's the rapid changes of colour and solid 'squirly' (I like that word) bits that I avoid and this policy has served me well over the past few years. I do avoid the intense solid centres (white on my aircraft) but generally have no problem with greens, yellows and sparse reds - as long as the build-up is gradual. As for the ride, I assume that if my tea isn't spilt, the Gin and Tonics in the back will be OK as well. As regards company policy, that is delegated to the crew - as it should be.

PM

Slasher,
You're of Nam, so with lots of tropical experience you know as well as anybody that flying through red is often times not an issue. All red means is there is lots of water, the colour itself does not say anything about the turbulence. But the shape and contours of the colours tell you everything...when accompanied by the appropriate tilt that is.

Back to the topic, our manual provides specific distances from cells depending on the phase of flight, recommending placing the aircraft upwind if at all possible. But when the squal line extends hundreds of miles, sometimes the only possibilities are to find a good enough hole or turn back (which I have never had to do as yet).

I too, have not heard of a turn back but I am sure there must have been a few.
I did a 180 in a 737 between Fiji and Wallis is. Wallis weather marginal in terms of cloud base but that's all. Cruising to Wallis the front ahead was the widest I had ever seen and real black. Moderate to severe clear air turbulence.
Unable to contact Wallis flight service due they had a radio failure so no weather updates. I approached within 40 miles of this solid cloud but nothing red on radar just a mess of green and yellow which turned out to be rain attenuation. I suspected embedded CB

Got the funny feeling I didn't like this one bit and did a 180 back to Nandi (Fiji) to fight another day. Landed and went to pub. Next day weather fine and reports came in overnight of Wallis runway previously flooded but water now receding. Landed Wallis and saw whole airfield lots of water but runway good. Was then told intense fast moving depression caused 75 knots winds at Wallis and all navaids knocked out including radios. Turning back was a good move after all.

Sciolistes
 

Had a captain who thought like you, flying into BRU large red circle right in our way "ahh there is not much turbulence in this region, that is just rain density" BAM, satic discharge that shocked all our senses............ Stay out of the rain if you have the fuel to burn.

If you think how to learn to fly airplanes by studying the FCOM, or any
company books for that matter, you have the wrong opinion about the profession. Experience does not come out of books.

Latetonite - you have misinterpreted my question. Rest assured I'm well aware that this game cannot be learned out of books (much like your grasp of the english language by the looks of things).

I am seeking information on industry practice so I can perhaps make a more informed submission to my management so as to get better words and guidance for our younger pilots.

It would seem a relevant answer is not available here..:ugh:

Our OM recommends avoiding intense echoes by 30nm and not flying through gaps of less than 40nm. These are recommendations only and discretion is left to the Commander.

Radar colours ?
 

If you examine the cross section of a mature Cb, you will find that the area of most water is associated the severe up and down drafts. It is therefore reasonable to assume that the RED area shown on the radar (lots of water) is the most turbulent. To say that the colours don't indicate turbulence is bordering on..........

...realistic.

Radar colours only indicate rainfall rate. Shape, size and especially gradient (green-yellow-red) must be taken into account to determine whether the CB is developing, mature, dissipating or non-existent.

I had the captain who would often dismiss the red area as being "just water"

He was right... about 4 out of the 5 times.

Color doesnt always mean turbulence or lack thereof. Just yesterday into central Florida the echos were close to each other and we went into areas where no radar return was shown...... But the ride was quite rough. These cells were building faster than could be displayed. Five minutes later would have cause a good fifty mile deviation. There was just no way to transit without some kind of pain. Don't like it, but Florida and the caribbean type storms can be given much less leeway than the mega storms of the American Midwest.

Try your best to avoid them if you're on a Chinese contract as apparently they'll deduct money off you for a lightning strike!? Comes out of your safety bonus at some airlines there I'm hearing...!

A minimum of 10 - 20 nm depending on altitude and storm characteristics.
Many experiences suggest aiming for greater distances.

“The effect of thunderstorms and associated turbulence on aircraft operations”. UK AIC: P 056/2010

One day had a B727 flt from MIA to KIN. APPROACHED A 200+ MILE LONG LINE OF CELLS AND MANAGED TO FIND ONE NARROW gap to get through. When we got to Kingston they were sending us back the same way with minimum fuel. I told them I wanted to go over Cuba and arrive from the south to avoid the line. We took a delay for more fuel for the reroute.

We always were within close range of a B757 from Montego bay to MIA so out of curiosity saw how their flight went. They diverted to Orlando because of their extensive deviations and for fuel reasons landed in Orlando. They were hours late. Going through gaps in the line like we did wasn't how I wanted to operate but it was the only way not to turn around. Knowing what you are facing you can fuel up and avoid having to make that decision.

Our company manual requires at least 10 NM from any echo associated with thunderstorm activity (even green) at FL200, at least 15 NM at FL250 and at least 20 NM at FL300 or higher. There is a lot of other guidance material, all in all a whole chapter just about thunderstorms.

10 miles below 20,000 and 20 miles above, preference up-wind. Another company same, but also had no approach to land if cell within 3 miles of RW and moving towards approach path. I have always taken this sort of thing as a guide, once again, common sense, local knowledge, experience etc etc. There are storms and there are storms. I always think some of the tropical beasts look worse than what they are and some of the little ones attatched to a cold front in cooler climates can beat you to death. I've had hail in clear air by being a little close. Must know the radar and how to use it, listened to a guy a few months ago going around "weather" on a clear night over Afganistan, he was going around terrain as far as I could make out. As for colour, even the green bits above 30,000 will put waves in your coffee.

Now many of us are waiting for you to write about those 1 out of 5 times cases. :hmm:

Thunderstorms
 

Sooner or later, even after taking much care to avoid them, you will enter a thunderstorm. Use common sense decisions and whether you go back, left or right, or through, hand fly the aircraft using attitude and not altitude.

Stay away from thunderstorms if at all possible.

Tmb