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ubreakemifixem
21st Jul 2007, 20:42
Does BA aircraft weather radar direct B747 and B777 to lightning?
After yesterdays terrible weather BA have at least 11 aircraft on the ground with multiple lightning strikes.I thought flight crew were trained to avoid lightning but I suppose some of the lightning was unavoidable.1 a/c had a direct hit on the windscreen,I bet that was scary for the crew! Brave people indeed.

haughtney1
21st Jul 2007, 20:52
Aircraft radar show precipitation rates, is essence where it is raining harder or conversely, less so. The radar doesn't give any indication of where or when lightning will strike....there is no real way other than a bit of meteorological knowledge and the application of common sense and experience to avoid lightning.
I've been flying an aircraft 40nm's from an active storm cell in clear air, and still been struck by lightning.

haughtney1
21st Jul 2007, 23:03
AMS, modern aircraft are constructed (bonded) in such a way that allows the massive electrical loads experienced in a lightning strike to be safely dispersed via static discharge wicks which are usually located near the wingtips and the vertical stabilizer.
There are cases where there have been minor injuries caused through electrical overloads.. e.g. a hot circuit breaker or two fizzing through the cabin, or a burn caused by arcing...but these events are quite rare.

theamrad
21st Jul 2007, 23:39
I remember a vague reference to a FO on some type(again can't remember but I think was jet) being injured during a lightning strike - apparantly he was leaning his elbow against the lower window frame when the strike happened. Maybe someone else 'round here might remember the details.

bereboot
22nd Jul 2007, 06:51
Actually I remember a BA 757 operating into AMS , where the FO was seriously injured with burning wounds on his arm , which was resting on the windowframe when it got struck by lightning.
Must been asome 5 years ago , can anybody fill me in on this ??

Basil
22nd Jul 2007, 11:01
Just to put lightning strikes into perspective:
I've only had one in a lifetime of flying - TriStar, approach, cloud outside starts to glow slightly pink, (could have been aircraft glowing due rapid static build up) huge BANG! (mentioned in Arthur Whitlock's "Behind the Cockpit Door") not a mark on the hairyplane :ok:

The static wicks should dissipate the static charge which may collect on the airframe during flight. In our case, I guess the build up was so rapid that the wicks' ability to discharge was exceeded.

The first line of defence is to stay away from Cb, which doesn't always endear one to ATC esp when one crosses a sensitive international border to avoid a long line of big 'uns.

punchus
22nd Jul 2007, 13:52
"Actually I remember a BA 757 operating into AMS , where the FO was seriously injured with burning wounds on his arm , which was resting on the windowframe when it got struck by lightning.
Must been asome 5 years ago , can anybody fill me in on this ??""
I think he was arrested after landing and charged.
It's a serious offence you know "flying while in possession of a dangerous firearm ":D:D

ray cosmic
22nd Jul 2007, 14:06
On the Fokker 50, first thing to fail after a lightning strike used to be the weather radar!:}

Aren't there stories around of these lightning "balls" traveling through the cabin after a lightning strike?

S1 C4 206
22nd Jul 2007, 15:10
I once took a large strike going into AMS at night on a 146. ( The aircraft had a poor wx radar.) The bang was so loud my chest felt winded , it felt as if we'd been blown apart. The Captain was temporarily blinded and we both sat there stunned for what seemed an age but I guess was only a few seconds. Fortunately, the autopilot stayed in.

The cabin crew reported a plasma lightning ball travelling through the cabin from rear to front and disappearing through the flight deck door. The smell was then quite intense, so we called a PAN and had priority vectors into AMS. (The smell soon after dissipated).

There was damage to the aircrafts elevator (entry point) and to panels high on the nose (Exit point).

I now always carry extra fuel if the forecast is for TS at the destination and have much respect for mother nature.

Longtimer
22nd Jul 2007, 16:14
Violent lightning strike brought down Kato Dornier 228
By David Kaminski-Morrow

Norwegian investigators have confirmed that a lightning strike, which severely damaged the tail of a Kato Airline Dornier 228-200, caused the aircraft to crash while attempting to land at Bodo airport during a storm.

Both pilots and the two passengers on board were injured when the turboprop, operating domestic flight 603 from Rost on 4 December 2003, struck the ground heavily just short of Bodo's runway.


Thunderstorms had been in the vicinity during the approach and Norway's accident investigation board, the AIBN, says the aircraft suffered a powerful lightning strike to the nose, which passed to the empennage and severed the central elevator control rod.

The AIBN says it destroyed the only connection between the pilots' control columns and the elevator, adding: "When the lightning struck the aircraft the pilots were blinded for approximately 30s. They lost control of the aircraft for a period and the aircraft came very close to stalling."

Despite the damage, the pilots used the elevator pitch-trim to regain a degree of control of the aircraft and attempt a landing. The aircraft's airspeed on the first approach was too high, however, and the aircraft bounced the crew aborted the landing and took the turboprop around for a second approach.

"Wind conditions were difficult and the next attempt was also unstable in terms of height and speed," says the AIBN. "At short final the aircraft nosed down and the pilots barely managed to flare a little before the aircraft hit the ground."

It says that the aircraft struck the ground 22m (72ft) short of the eastern end of runway 25 and slid 78m before coming to a halt. The heavy impact, around 8.4g, crushed the underside of the fuselage and damaged the propellers. The aircraft, a 16-year-old example registered LN-HTA, was written off.

"There is reason to believe that the total amount of energy in the lightning exceeded the values of the construction specifications," says the AIBN, although it points out that up to 30% of the wiring in bonding connectors in the tail may have been defective before the strike.

In its report into the accident the AIBN has made three recommendations, centred on increased attention to maintenance, better use of airborne weather radar, and improved presentation of ground weather-radar information by air traffic control.

Sleeve Wing
22nd Jul 2007, 17:05
When I first started airline flying, I had the good fortune to fly quite regularly with a very experienced captain.
He had also been an AEW pilot and, as you know, these aircraft carry a very powerful radar and large aerial.
His advice was always to have a good look at the radar picture to confirm where the "weather " was. He would then take up clearing headings,(with permission of ATC) switch the radar off for a while and then check the situation again after a few minutes.
Never failed !
The theory was that, as the lightning will take the shortest path, it will follow the return signal of the nearest radar - in this case, us.
Always worked for me, apart from a couple of times, in over 25 years.
Just luck ?.....or anything in it.
Oh, and re: plasma balls (ionised gas) down the aisle, apparently a regular occurrence in 707s.

Sleeve.

rubik101
22nd Jul 2007, 17:45
I was much amused, very non PC I know, to read the article in today's Indie.
A door to door bible salesman in Miami was struck by lightning under a clear, cloudless blue sky! tee hee.
It just goes to prove that there is a Devil after all!

ChristiaanJ
22nd Jul 2007, 18:17
... Does BA aircraft weather radar direct B747 and B777 to lightning? ...... The theory was that, as the lightning will take the shortest path, it will follow the return signal of the nearest radar ...
If I read this correctly, there is some kind of belief, that a weather radar "attracts" lightning.
Could somebody elucidate? I've never heard of this.

F4F
22nd Jul 2007, 18:36
Avoiding lighting strikes is akin to avoiding insects splashing on the windscreen... it's all a question of how rapid you are :p


live 2 fly 2 live

ciderman
22nd Jul 2007, 18:42
Nothing attracts lightning like 3 miles of wire out the back of a Canberra. I was struck off the Scillies in gin clear weather. Put one of the old Avons out and punched several dozen holes in the bomb bay doors. Made my mate lying in the nose get his ass back in Martin Baker's finest double quick I can tell you. As they say it can strike anywhere. As for the "bonding", even through kid gloves I felt it. Doesn't last forever that "bonding"!!

llondel
22nd Jul 2007, 18:43
If I read this correctly, there is some kind of belief, that a weather radar "attracts" lightning.

If you're projecting a beam of ionised particles then you might provide a favoured path for lightning to flow. However, I wouldn't want to be near a radar set powerful enough to do that.

Mungo Man
22nd Jul 2007, 19:10
The radar doesn't give any indication of where or when lightning will strike....there is no real way other than a bit of meteorological knowledge and the application of common sense and experience to avoid lightning.

No real way to show lightning... apart from the LSS (Lightning Sensor System) on my aircraft which is independent from the Wx radar, and shows lightning within 100nm radius.




http://i125.photobucket.com/albums/p79/Skippymon/LSS.jpg

TURIN
22nd Jul 2007, 20:14
Just to add to the tales of daring do....

Mate of mine on the headset during a pushback (1-11 I think) at MAN, bolt of lightning grounded within a couple of yards, all went very quiet until the flight deck could be heard urgently "...eng? eng? you ok?.."
Like a true professional our man blinked away the tweety birds and stars and continued the push.

His name was Nigel too. Does that count? :ok:

ChristiaanJ
22nd Jul 2007, 21:32
Nothing attracts lightning like 3 miles of wire out the back of a Canberra.Ouch......
I agree that IS asking for it..... Glad to know you lived to tell the tale.

If you're projecting a beam of ionised particles then you might provide a favoured path for lightning to flow. However, I wouldn't want to be near a radar set powerful enough to do that.There are no radar sets powerful enough to do that.... microwave radiation is not ionising radiation... certainly not at the level transmitted by a weather radar.

No real way to show lightning... apart from the LSS (Lightning Sensor System) on my aircraft which is independent from the Wx radar, and shows lightning within 100nm radius. Mungo Man, you triggered what must be a 20-year old memory, called StormScope. Good to see it still exists and still serves a useful purpose.

Anybody has any more info about what appears to be an urban legend (an aerial one in this case) ?

Yacov
23rd Jul 2007, 01:24
RE
''I was much amused, very non PC I know, to read the article in today's Indie.
A door to door bible salesman in Miami was struck by lightning under a clear, cloudless blue sky! tee hee.
It just goes to prove that there is a Devil afte'' SNIP

Maybe it wasn't an authorized version? In which case God allowed the sky action:)..
and proves He watches over His Word:)
y

Coastrider26
23rd Jul 2007, 02:40
Actually I think the system Mungo man is revering to is a E135/E145 which is a quite new plane. The E170-195 series which is well ahead of it's time has the same option, also will paint areas of turbulence unfortunately that function does not detect CAT.

gengis
23rd Jul 2007, 04:34
Many higher performance General Aviation airplanes beginning in the eighties used to be equipped with a cheaper alternative to weather radars - Storm Scopes. Unlike our radars which detect wet precipitation, storm scopes worked more like ADF's by tracking areas of electrical discharge in clouds. Some airplanes were even retro-fitted with both storm scopes & weather radars by extravagent owners. To identify areas of high electrical activity (and hence likelihood of lightning strikes), Storm Scopes are probably better than weather radars. In essence however, both of these types of equipment serve to identify where the storm is, and hence their avoidance - not to encourage penetration of it.

As to the effect of lighting strikes on a person, much has already been said. The Physics description of this is a "Faraday Cage" - where the electrical current is conducted around the metallic exterior of the vehicle, not the inside, thereby protecting the occupants.

I once had a lighting strike on a B777 passing 13000' during descent through "green" radar returns. It struck on the right side just behind the radome. The First Officer was none the worse for it, as was the airplane. Up till that time, i was privately skeptical about how a highly electronic airplane like the 777 would hold up in a lightning strike - as it turned out, there was not even a flicker in any of the instruments EFIS/FMC/AFDS/COMMS/RADAR/stby compass.... nothing. Once on the ground i discovered where it struck and the only thing was a couple of burned out static wicks. I've been a fan ever since.

boris
23rd Jul 2007, 11:38
Lightning sensors (Stormscope) were integrated into the radar display and were specified as original equipment on Jetstream 41 aircraft that were delivered to BRAL/Loganair.

The reasoning was that these aircraft would be spending their flying lives at or below FL250, where there is a greater risk of strikes and were specified, not by "extravagent owners", as gengis put it, but as a cheap addition to assist crews avoid both lightning and cb activity, which are not neccessarily co-located. Pilots liked it too.

The commercial payoff was that there was a significant reduction in reported lightning strikes on the J41 compared to the ATP which was not equipped with sensors; thus less engineering time was spent on lightning strikes and their aftermath.

Because of this good experience, a similar fit was ordered on the EMB145 although Embraer took a little time to get it installed.

It was a cost and safety effective tool as far as we were concerned. Bit like the talking checklist really, but that's another story.

Julian Hensey
23rd Jul 2007, 12:11
Take a seat for some testing - any volunteers? :uhoh:

http://sciam.com/media/inline/000DBD54-3835-1C71-84A9809EC588EF21_arch1.jpg

Evening Star
23rd Jul 2007, 17:15
Actually I remember a BA 757 operating into AMS , where the FO was seriously injured with burning wounds on his arm , which was resting on the windowframe when it got struck by lightning.
Must been asome 5 years ago , can anybody fill me in on this ??

AAIB link (http://www.aaib.gov.uk/cms_resources/dft_avsafety_pdf_500760.pdf)

towrope
23rd Jul 2007, 20:57
Adding to the plasma ball in the PAX cabin.... ages ago when I was a lad I was in a 707 from HNL to SEA when we were hit. Had a lovely plasma ball dance its way along the seat tracks the length of the cabin. I of course thought it was the neatest thing in the world but it was a minority opinion. :rolleyes:

rubik101
23rd Jul 2007, 21:13
Towrope's story reminds me of my dear old Mum who relates the tale of a plasma ball in a 707 on the way back from Bermuda many years ago. She says it took several seconds to travel from front to rear and left a very interesting smell! The hairs on her arms apparently took the rest of the flight to lay back down. I was oblivious to it all, asleep in my crib! (so she tells me)

Whiskey Zulu
23rd Jul 2007, 22:24
As cabin crew, I witnessed a similar event in the cabin of a B757 many years ago. In rather turbulent conditions, a ball of lightning flew down the entire length of the aisle from front to back and seemed to exit via the R4 door. Pax were cr@pping themselves. An attractive young female asked if I would "hold her hand if we were going to crash," to which I reassuringly replied "sweetheart, if we we're going to crash you'd be holding my knob not my hand!"
On a separate flight, again on a B757, the left wing was struck by lightning during the latter stages of the descent. Sounded like the No.1 engine had exploded! Uneventful landing followed, without the Captain even making an explanatory PA to the rather concerned passengers.

anotherthing
24th Jul 2007, 00:40
.....back of a Canberra. I was struck off the Scillies.....

I'm not a doctor, but that sounds painful to me :p

moggiee
24th Jul 2007, 01:19
No real way to show lightning... apart from the LSS (Lightning Sensor System) on my aircraft which is independent from the Wx radar, and shows lightning within 100nm radius.

Our Diamond DA42 has a Storm Scope which does a great job of showing you where the lightning is - useful on a carbon fibre composite aeroplane! By no stretch of the imagination could it be described as an "extravagance"

FlyingConsultant
24th Jul 2007, 15:42
modern aircraft are constructed (bonded) in such a way that allows the massive electrical loads experienced in a lightning strike to be safely dispersed via static discharge wicks which are usually located near the wingtips and the vertical stabilizer.

Probably a stupid question: I assume "bonded" refers to composite materials. How do the modern composite designs deal with this? My experience with composites is 15 years old and was very limited, but IIRC, the composite components do not conduct electricity that well, and might not take the heat from an impact as well as metal (could be wrong of course). While big portions are still metal, aren't some only composite? I am sure they found a solution (or this is not a problem)....but how?

ChristiaanJ
24th Jul 2007, 16:00
I assume "bonded" refers to composite materials.It doesn't actually. It refers to the (usually flexible) metal strips that electrically connect moving parts (like controls surfaces and flaps, or doors) and removable parts (think tail cone, for instance) to the main aircraft structure. If those strips are absent or defective, the current from a lightning strike can take highly undesirable paths, such as via actuators or control rods.
As to the behaviour of composite materials during lightning strikes, I have no idea either. I hope somebody else has some answers on this. I would have thought the "bulk" electrical resistance of composite materials would be a lot higher than that of aluminium.

gas path
24th Jul 2007, 17:27
Looking at the 777 that was whacked on the left engine D duct, the composites don't fair too well! In this case the translating sleeve has got to be replaced and one of the fan cowls requires extensive repair.
One wonders how the 787 will cope, or indeed the 350 with its 'plastic' wing.:suspect:
The D duct has several holes where the composite filaments have shattered with the resin being destroyed, as the lightning passed through and out of the the duct it has also delaminated the trailing edge. It appears that the 'bolt' passed from left to right and exited (with associated damage!) through the right wing damaging the outb'd aileron and tip.

atakacs
24th Jul 2007, 18:09
After yesterdays terrible weather BA have at least 11 aircraft on the ground with multiple lightning strikes

ouch ! Any significant damages ?

overstress
25th Jul 2007, 02:44
I was in the rather smelly hold of a C130 on approach to Deci (Sardinia) which was struck. There was a tremendous bang and a ball of lightning appeared and headed off to the ramp at the rear, where it disappeared.

The lower VHF blade antenna had been blown completely off, with other damage elsewhere on the outer skin.

qfcabin
25th Jul 2007, 07:44
30+ years at it from Electras through to 747/400s and only twice was i shaken up badly..both strikes..one on descent into ATH..rhs of 747 struck between R1 and R2 doors..exactly where i was working..sounded as if we had been machine gunned and when the guys checked after landing, there were about 25 holes along the fuselage, even looked like large bullet holes.
Other was NAN/HNL.707/138..just the one hit... rhs again but loudest thing I've ever heard..the shakes and sweats didn't start for a couple of minutes but they lasted a bit longer.And no marks on the fuselage!

28L
25th Jul 2007, 17:15
Evening Star,
A couple of interesting points included in that AAIB report:
1) BA appear to fly the 757 single crew with no pax, and
2) The Commander had 234 flying hours in the 90 days previous to the incident. Who says BA pilots don't earn their keep? :ok:

FlyingConsultant
26th Jul 2007, 16:50
the composites don't fair too well! In this case the translating sleeve has got to be replaced and one of the fan cowls requires extensive repair.
.......
The D duct has several holes where the composite filaments have shattered with the resin being destroyed, as the lightning passed through and out of the the duct it has also delaminated the trailing edge. It appears that the 'bolt' passed from left to right and exited (with associated damage!) through the right wing damaging the outb'd aileron and tip.

I have to admit I cannot follow this completely, but the description does not surprise me. From what I remember (could be wrong with more modern composites) these materials do not conduct electricity very well. One could conclude that they are less likely to be hit (no idea but I would guess that's true), but the problem is that there is still plenty of metal in and around the stuff. So lightning will ultimately find the metal - but on its way it will heat up the composites very rapidly. They don't take that too well. In addition to the bonding agent, depending on thje composit, some have air and gas bubbles, and in some cases water embedded, which I guess would explovely expand, leading to local delamination. Oops

On the other hand, it's such an obvious question that somebody must have thought about it, so I assume (stupid me) that there is nothing unsafe here. Just very expensive to repair.

gas path
26th Jul 2007, 17:28
On the other hand, it's such an obvious question that somebody must have thought about it, so I assume (stupid me) that there is nothing unsafe here. Just very expensive to repair.
The composites are made from carbon filaments and IIRC the structure also has a fine mesh bonded in to it. The carbon will conduct at the +ve here.
In the case of the D duct it looks like one of the major stikes hit a panel screw .....and welded it in! then tracked fore and aft exiting along the trailing edge of the duct.
Nothing too unsafe and yes very expensive!

Swedish Steve
26th Jul 2007, 20:46
Speakin as an engineer I have seen many aircraft with lightning strikes, but the worst damage was a line of 13 burnt rivets across the L1 door. The reason aircraft get grounded is that you must inspect the aircraft which requires a high lift, and usually there is more than one aircraft hit, and only one high lift.
The only emergency I witnessed caused by lightning was a DBA F100 which was hit at rotation. The lightning knocked out BOTH engine oil pressure transmitters. So the crew got two ECAM warnings, each one warning of low oil pressure and recommending engine shut down. Being quick thinking, after shutting down the left engine, they decided to keep the right engine running for a quick circuit!

ahramin
27th Jul 2007, 04:26
There was a fiberglass glider in the UK hit by lightning several years ago and it simply exploded. The moisture in the fiberglass turned to vapour and split the thing apart. Both people parachuted safely.

Though obviously this not the same fiberglass process as the airline manufacturers use.

Frangible
27th Jul 2007, 14:15
The story of the glider went into an AAIB report, complete with pix, on the investigation of a Super Puma ditching after losing the tail rotor. Very technical investigation on lightning resistance and they found, as FC mentioned, composites have very high resistance to conducting electricity, but when they do, things fall apart. In this case the metal strip on the blades couldn't cope. The only reason they did not all perish, and managed to autorotate, was that the tail rotor assembly was held on by the hydraulic line.

AAIB then recommended far far higher standards for lightning resistance as the load which caused trouble in the north sea was tens of times stronger than the worst case scenarios devised when designing the lightning standards. Nothing has been done though, despite greatly increasing use of composites.