Flying through a Thnderstorm

[Mustang]

thats one scary ride! The St.Elmo's fire on the glass is awesome, never seen it before :)

[capttrob]

Looks pretty typical of flying the leading edge of a cell. That was pretty tame though... light to mod chop. The AP didnt even kick off... Im surprised those guys didnt have fun with St Elmo though. If you put your hand on the windshield, you can "drag" the static electricity around like one of those vandegraaff generator glass balls you see at Sharper Image...

 

Now you guys know what its like on a typical summer evening in the midwest at the flight levels... :thumbup:

[Guest IguanaKing]

Wind shear though...not a big fan of it. As they say...been there, done that, got the...healed spinal fractures. I wonder how that St. Elmo effect on the windscreen affects the WS heat circuitry. It can't be a good thing.

[capttrob]

We never had problems with WS heat and St Elmo. Its more of a problem with VHF interference. While flying through high altitude super cooled precip we actually hear the static over the freq increase as we fly along.. then WHAP!.. no more static... then it would start to build again...till the next WHAP! Fun times...lol

 

I hear the most exciting light show is in turboprops when St Elmo grabs ahold of the prop tips. I used to fly a Corporate King Air years ago, but never had the pleasure of seeing it....

[Rhen]

Not that I've noticed, although it makes HF radio transmission and reception pretty crappy.

[Guest IguanaKing]

Heh...not to mention completely negating ADF and LORAN.

 

WS heat might be more tolerant than it looks...but MAN those wires are small.

[capttrob]

IIRC from ground school (when i was awake), WS heat isnt effected very much because it has several layers of glass (excellent insulator) and heat itself increases resistance for any conductor. But, i could have just been waking up when that was taught.. so dont take my word for it... :smartass:

[Guest IguanaKing]

You could be absolutely right, but the voltage involved is pretty high. I lost count of how many times I have been nailed by the HV in a transponder. Its only 1400-3500 volts, but it travels fairly well across the world's best insulator...air. You don't even have to touch it for it to bite you. I've gotten to the point where I don't use a probe any more to check the HV bleeders. Not stupid enough to try that with a radar yet though...I'll just continue using my HV probe for those. ;)

[capttrob]

I would guess the voltage on the WS heat wouldnt matter much since its mostly 115 AC and not looking to hold hands with St Elmo (havent seen a DC windshield heat yet.. although im sure there are some.. maybe those ice plates). St Elmo is looking to discharge somewhere, and although he has a good push, i believe he is looking for the path of least resistance. Same as the windshield AC. So i figure they both go on their merry way... Besides, since WS heat is mainly used in icing conditions (although some aircraft sop is on all the time), and St Elmo loves the ice, im sure there is some kinda shielding involved there. However, he loves to find VHF. :pilotfly:

[Guest IguanaKing]

Yup...the voltage on WS heat is 115 AC, 26 AC, or 28 DC. The point is...its equipped to deal with those voltages. The 10,000+ volts from SEF...well...its a little higher than what many of those components are designed for. :D

[capttrob]

Best to ask an A&P i suppose. I know i learned this stuff, but since we never had a problem its never fresh in my mind. Im pretty sure there are some bonding cables from the WS metal frame to aircraft ground. Being that there are several layers of glass, combined with air in between, i guess that is why i've never seen a problem with WS heat.

 

We did however have a rash of problems with windshields shattering in flight on the 328 when we first started flying them. That was lotsa fun, especially at 28,000 feet...lol. One day we were climbing out of Laguardia enroute to Columbia, SC (CAE). Im pilot flying as FO. The Capt was telling me about a windshield that shattered on him the day before. As im leveling at FL280, we hear a loud bang like the nose gear came down on its own. We look around to see what it was, as we both look to the left, the whole side windshield on the Capts side is "spider-webbed".... HOLY CRAP! We're at 280! Drop the power, call the emergency and start the sucker down. ATC "clears" us to FL180.. we both laugh and tell him we are going to 10,000 now so clear below us. He clears us to 6000. Im setting up the approach into Philly and working comm 1 as the Capt is on comm 2 with company. Guess what the company wants us to do? They want us to nurse the thing all the way down to CAE since it was one of our MX bases and we had the fuel to go low.... we're just north of Philly! No freakin way are we flying all the way to CAE with a cracked windshield and passengers! So he tells them its Philly or back to LGA.. take your pick and do it quick because we're on the approach for PHL now. They choose LGA and we head back.. uneventful. We had a 3 month stretch where our fleet was shattering windshields every other day in the Dornier. You should have seen the look on the pax faces as they de-planed and saw our windshield... priceless...

 

Sorry to be a chatter-box... but this thread reminded me of that story.. and its fun to tell...:D

 

Turns out the frames werent set properly from the factory, after those 3 months and they figured out the problem, havent had a windshield shatter since.... but we did go through our growing pains with that airplane and rashes of other problems... the stories i have... lol

[Guest IguanaKing]

That IS a funny story, glad you made it through okay. Did you guys dump cabin pressure like there was no tomorrow? I'll bet you did.

 

BTW...don't call me an A&P...them's fightin' words to a guy like me. :smilewink:

[capttrob]

Here are some pictures of one of our birds that is now nicknamed "The Lightening Rod". She was more than 20 miles rom a cell when this happened... i forget what altitude. The Cell reached out with a nice big kiss.... she made it back to CVG no problem. The pilots didnt even notice a big difference in flight except a loud bang. They chose a "pre-cautionary" landing back at CVG just in case and to see what it was that hit em. They were in Clear air IIRC deviating around a large cell when this happened.

 

 

Two picture include the damage and the last is the repair...back in service. Nice paint huh? lol

[capttrob]

That IS a funny story, glad you made it through okay. Did you guys dump cabin pressure like there was no tomorrow? I'll bet you did.

 

BTW...don't call me an A&P...them's fightin' words to a guy like me. :smilewink:

 

Not calling you an A&P... just saying its better to ask an A&P... since they install windshields...:D

 

We didnt dump, we just raised the cabin a bit. We were coming down like a refridgerator anyway. We didnt want to cause too much diferential too rapidly... The windshield held intact. Matter of fact, our company released a read-file later saying it was ok to continue to destination if it was a mx based when this happens, and the feds signed it off...lol. They had all kinds of diagrams and inflight procedures for the pilots to test which pane of glass had shattered. A freakin joke imo. Our pilots agreed if we had anymore windshield "incidents" we put the thing on the ground.. period.. regardless of the read-file. It wasnt long before they fixed the problem the right way....

[Guest IguanaKing]

Roger that Captain. I guess I get used to people confusing us. We work on stuff inside the firewall/forward bulkhead...they work on stuff outside of that. The major difference is, we avionics techs look at an engine or airframe problem and tell the customer "I'm sorry...you need someone else for that, as I haven't got the first clue." Bad A&Ps, not all the time (and I don't mean to offend A&Ps on the list), don't care what question you ask them...THEY can fix it. A&Ps worth their salt know when to consult avionics inspectors such as myself, just like I got to where I am by saying, "Hey, I don't know squat about your landing gear problem, but I know a guy who will hook you up, he's an A&P and I trust him.".

[britgliderpilot]

Here are some pictures of one of our birds that is now nicknamed "The Lightening Rod". She was more than 20 miles rom a cell when this happened... i forget what altitude. The Cell reached out with a nice big kiss.... she made it back to CVG no problem. The pilots didnt even notice a big difference in flight except a loud bang. They chose a "pre-cautionary" landing back at CVG just in case and to see what it was that hit em. They were in Clear air IIRC deviating around a large cell when this happened.

 

 

Two picture include the damage and the last is the repair...back in service. Nice paint huh? lol

 

Can do better than that :P

 

 

 

 

 

That damage was done before the aircraft hit the ground . . . . .

 

Astonishingly, both pilots parachuted to safety - sum total injuries were damaged eardrums, singed neck, and a broken ankle.

[diveplane]

thought modern planes where resistant to lightning?

can you guys explain to us rookies what happens?

 

............whats elmos fire?

[Guest IguanaKing]

St Elmo's Fire is a phenomenon caused by differential electrical charging of various parts of the airframe. Due to this differential, parts of the aircraft can actually, visibly glow with the displacement of electrons. The very movement of air over the skin of an aircraft can build a HUGE electrical charge, in much the same way you can build a charge on the ground by shuffling your feet on carpeting, or by rubbing a balloon on your head. Of course much of this depends on atmospheric conditions. Thunderstorms bring higher electrical activity, but they ALSO bring higher humidity, which helps to dissipate said charges. Most aircraft attempt to defeat most of this through the use of static wicks. These are high-impedance devices, usually on control surfaces that try to equalize electrical charges between the aircraft and its surroundings. It isn't always fast enough though...and good COM and NAV reception can even depend on the quality of the electrical connection between your airframe and items like flaps and landing gear doors.

[britgliderpilot]

Quote from the glider accident report:

 

Damage to aircraft from lightning strikes can result from both 'direct effects' and 'indirect effects'.

The former is characterised by damage caused by the attachment of a lightning arc to, or the

passage of lightning current through, the airframe. Indirect effects relate to damage or the upset of

electrical/electronic systems by transient currents and voltages induced by the lightning current. In

the subject glider, only the direct effects were relevant, and these could be split into three

categories. Firstly, Joule heating generated from the passage of lightning current through

conductive components; secondly, localised heat damage and erosion where lightning arc roots

attached; and thirdly, the damaging effects of lightning arcs and resultant shock waves and

overpressures within the glider structure.

The Joule heating generated is proportional to the time integral of the power dissipated, ie

heat = ∫i2.R.dt , where i is current measured in Amps and R the resistance at any point measured in

Ohms. The parameter ∫ i2 dt is referred to as the 'Action Integral' in units of Ampere2seconds (A2s),

which is equivalent to Joules/Ohm of component resistance, R. Since lightning can be considered

as a current source, this parameter is a measure of the energy potential for a particular lightning

strike to cause severe Joule heating and arc affects.

[Guest IguanaKing]

Heh...and some aircraft that regularly survive, seem to have an affinity for lightning. I once worked on a Piper Meridian that had been struck no less than 9 times in its first year. We have all joked that its paintjob singled it out. It is plain white, while other Meridians are white with all kinds of red, blue, and/or gold striping on them. Mr. lightning strike, however, was solid white, with plain, black lettering. Maybe god hates an ugly airplane.

[LawnDart]

capttrob,

 

Don't mean to pry or go too far OT, but where are you at now (considering ACA's and more recently, Independence Air's demise)?

 

I've had the windshield on the ERJ go "ka-boom" and shatter into a spider-web pattern on my side at 30K once. That certainly gets your attention!

 

BTW, the windshield heat on the "Urge" is 28VDC.

 

LD

[capttrob]

capttrob,

 

but where are you at now...

 

 

On the couch, laptop in lap, email browser open in the background sending out the resumes while sayng to myself repeatedly, "Im not going to another regional, Im not going to another regional." in the same tone as Dorothy. :thumbup:

 

Im even afraid to go to jB if i get the call, the way things are going. I thought about Netjets, but i may just go back to Corp if i can find a good gig. I'd really like to get into the software biz actually. So if anyone knows a developement or controller company looking for pilot consultants, feel free to drop me a line..;)

 

For now, im enjoying my time off doing some day trading in between slinging heaters and slammers... Im also thinking about getting my Series 7 and going into the financial industry. I figure if you cant beat guys like JO, might as well join em....lol

 

Who you with Lawndart? I've seen you post over at flightinfo but didnt catch which airline....

[Guest IguanaKing]

Capt...have you tried Flight Options yet? Just a thought, dude.

 

I'd recommend ATG to you, but they've got enough test pilots already. Damn good program though...being funded by IAI.

[capttrob]

Yeah, i've thought about all the frac's. Problem is, i need to make up my mind if i want to stay in the industry as a pilot. After many years at ACA, its hard to start at the bottom again. If i do go frac, i'll probably try NJA first since its like "ACA Part Deux" as many of our guys went there.

 

Im thinking it might be best to get a stable "working stiff" 9-5er and fly on my own time. I've seen too many lives ruined in this industry. Guys with homes, families to support, getting put on the street with the only option to take a 75% paycut if they want to start at another airline. We really do need "one-list" in this industry. I am also thinking of getting my avionics cert. Have any recommendations for schools?

[capttrob]

thought modern planes where resistant to lightning?

can you guys explain to us rookies what happens?

 

 

IK handled the SEF question or ya... i'll try to tackle the lightning one... :)

 

Its not so much that modern airplanes are "resistant" to lightning. Its more like they are configured to be a part of the lightning bolt so it passes through the airframe quickly without resistance on its way to the ground. older airplanes have wood and such in them which would explode when hit by lightning in the olden days.... I think we had some wood in the rudder of the 328 and that is why it exploded like it did. It was just bad luck where it hit i guess. Here is a good picture and video of a 747 departing out of Osaka that shows what im talking about.

 

http://www.crh.noaa.gov/pub/ltg/plane_japan.php

 

If you do a google search for airplane lightning strikes, you may find some pictures of small entrance and exit holes in the airframe from where the bolt passed through. :pilotfly: