Flight around Cyclones/Hurricanes?

[TOPC]

Could those pilots who have had any experience with Hurricanes and Cyclones please explain the most accepted avoidance/penetration procedures adopted by most airlines.IE which side to fly ,where would you expect the greatest and least turbulance,notable anomalies and dangers around the cells heaviest rain areas etc.
Any info appreciated. THANKYOU.

[TOPC]

Does anyone know of a good aviation Met site perhaps?
Thanks in advance.

[redsnail]

I used to fly near them when in Oz. However I was in little things (C207-Bandits). You might try Bureau of Meteorology (http://www.bom.gov.au/lam/)
If you're in bigger jets and the like you might be better off getting advice from the guys that fly through the ITCZ.

[Notso Fantastic]

TOPC, in the Northern Hemishere, air circulates anti-clockwise around a depression, so that is the way to go to minimise your exposure. When the last really major storm was approaching the Carolinas, we were planned to Miami almost along the coast. The edges of the storm according to the latest piccie were just off the coast. I had major misgivings about flying so close and we had replanned a good alternative route further inland ready. As it turned out, we were just inland with a grandstand view of the edges of a major hurricane, and no turbulence. When we left just over 24 hours later, it was still only half ashore and we went east out into the Atlantic and round the back of it, again impressive weather scenery and no problems.
I don't think there are any hard and fast rules of mixing hurricanes and aeroplanes (except keep latter out of the former). The only people who really know are those US crews who fly the weather ships (Hercs and Gulfstreams I think) right out into them routinely. They must be head bangers, but also very knowledgable. I wish there was a way the airline community could tap that knowledge!

[palgia]

Notso,

a hurricane is actually a warm core low, where at upper levels air circulates CLOCKWISE in the northern hemisphere (high pressure). Just somethng you might consider when planning the most favorable side to plan/divert around a tropical storm or hurricane.
The strongest winds will be at the surface and diminishing with height (this refers to the horizontal wind speed, not to the updrafts/downdraft in the convection)
Except for the convective band closest to the eye, or for particularly severe hurricanes, the hurricane cloud tops are generally LOWER than for isolated severe thunderstorms in the same area (that excludes some isolated overshooting tops, which normally do not last more than 15-20 min). This means that it might be possible to overfly a large part of the hurricane (I believe this is what the hurricane hunters use their gulfstream for, data acquisition while overflying the hurricane. On the other hand, they normally use the props for penetration into the eye at lower altitude).

palgia

[TOPC]

So as I understand there is no area at the higher levels that will produce more turbulance than lower levels.Is it fair to say that you would therefore plan around the side of the hurricane/cyclone that gives you the best tailwind component ?

[LEM]

Never seen one, but our met instructor once told us hurricanes actually concern sailors, not pilots.


If you just have to overfly it, of course...
Landing in the middle of one is a crazy idea.

[XTRAHOLD]

You should try to avoid these beasts at all costs because global warming is making them meaner and stronger year after year; however, if it so happens that you have to get around one of these, let me tell you what I have experienced. There should not be such a thing as an airline dispatcher sending you purposely into a cyclone or typhoon, BUT if the airport conditions are "operational" regarding visibility and crosswinds, you may get sent into harm's way never the less. As captains, we are risk managers and are constantly assesing how much to take and manage it wisely so to make the final decision of when it is not safe to continue. Well, when you fly into airports affected by these monster weather machines that risk is changing so fast and so often that what seemed safe a few seconds ago, suddenly becomes deathly the next instant you are reassesing your situation [A true russian roulette] . Your airspeed will be all over the place on your speed tape (On EFIS equipped aircraft) and your best energy indication will be your groundspeed readout coupled with your attitude and power settings. The autopilot and autothrust will not be able to compensate quickly enough so be ready to fly the approach manually as early as possible. When you fly around one of these things, you usually will have the outer edges pretty well defined and beside the increase in tailwind around the SE and NE quadrant you will not find too much to complaint about. The edge (Which by the way, is not defined at all) between the Northeastern and Nortwestern quadrant are were you will start getting whacked around violently and most of this Northwestern quadrant will have some pretty severe turbulence, so bad in fact, that you will not feel safe enough to extend your flaps for an approach. In our case, we diverted to our alternate airport and waited a couple of hours till the cyclone moved north a bit. On my second attempt I landed in what could still be called the south eastern quadrant and had the most extreme rainfall I had ever experienced, just like flying into a fireman's hose but the turbulence had decreased to a more moderate level. The wind on a 20 NM final went from a 65 knot tailwind to a 15 knot left crosswind at 50 feet over the treshold. The precip was so intense the localizer signal grounded out (The aircraft was a B-737NG, a phenomenon(EFIS LOC display loss) that also occured to me in a B-737-300 in a blizzard some years ago) on short final, fortunately we had the approach lights insight and could continue visually to complete the power on landing. You may be asking yourself why continue the approach under those conditions? Well there is not an easy reason but you have to look at the whole situation, the areas we had alraedy flown through, the few aircraft that also had landed ahead of us and just the prospect of the go around was even worse given the conditions over the missed approach path.
So there you have it, experience from making a questionable decison in the first place. What seems operational on the dispatcher's desk may seem totally different from that left forward seat. My advice again AVOID, AVOID, AVOID!

[moo]

Just a quick question for those operating big jets - if you should see bad wx on your radar, how do you go around it? I mean, the FMC has all your waypoints set up and the course between each one will be flown by the autopilot. Do you have to disengage the autopilot to make a turn around it? If you are over somewhere where HF radio is your only contact with ATC, do you have to tell them you're going around the bad wx or do you just do it and re-establish your route to the next waypoint when you've safely got around it? Typically how much do you have to turn to avoid it, is it just a few degrees or a whacking great course change?

[TOPC]

Xtrahold.I can appreciate the the economic pressures placed on all of us these days .The majority of times I have been lucky and the majority of experiences I have had involved Thunderstorms.In fact One of the hardest decisions I have had to make was out of Brisbane in Australia.We timed it to perfection by arriving at the threshold for takeoff as a black/green rollcloud moved toward us.A local operator in a 737 behind us was keen to go.I decided to wait as the radar was full of hook shaped chasms within 5 NM .We took next exit and he took a visual departure with an immediate turn away from the cell.His takeoff roll was normal his rotate was slow as was the initial climb.At approximately 300-400 feet he made a left turn which rolled violently passed 45 degrees before recovering and climbing normally.Twr asked him if operations were normal.Terrifying to watch .However he would probably have been on time to his destination. Tower reported winds veered 150 degrees gusts 30 to 52 knots. Thereafter followed one of the most violent hail storms I have witnessed.I was 2 hours late to destination .

[patrickal]

Maybe you want to invite someone from this site to respond.

http://www.hurricanehunters.com/

[*Lancer*]

moo,

Firstly you need a clearance to go off track... it's usually available unless there is converging traffic. ATC will ask you you to report back on track, or be on track by a certain point (they generally like you on track by an FIR boundry to complify coordination - but thats not always achievable).

Then you leave the FMC and fly headings around the weather. It would be unwise to disengage the autopilot, as conditions around a storm can significantly reduce the performance of the aircraft.

The turns aren't usually large, as you've started generally them 60 odd miles away from the storm. Things can get a lot busier if a clearance takes a while, or if the storm is in the way of terminal maneovering...

Lancer

[srjumbo]

Lancer and moo
Occasionally if you are over the Atlantic or Africa there is no time to request a track offset so you TELL the controller that you are offsetting by twenty miles or so. Aviate, navigate, communicate!

[TOPC]

Patrical.Thanks for that,Have emailed them and will post their response.
Cheers:ok: