Let's hear from the old schoolers

[Lead Sled]

Why kind of airplane were you in, lead sled.

An Astra.

LS

 

[Princedietrich]

I should bring this up to my boss. He said I would get a raise when pigs fly.

 

[Spooky 2]

Here's a link to a 1960 article on the subject: http://www.time.com/time/magazine/article/0,9171,894885,00.html

I don't believe there's ever been a case of lightening or a static discharge igniting Jet A, though there have been cases of lightening causing aircraft losses (and explosions) when fueled by Jet B (which is cut with gasoline, vs. purely kerosine).

So far as the danger itself; St. Elmo's can progress from a harmless display to a static discharge fairly quickly, and can certainly cause structural damage, though generally not to the degree of a lightening strike. A lightening strike, on the other hand, may cause damage ranging from a small burn hole going in and going out, to blown off radomes, blown out electrical panels, failed avionics, etc. A lightening strike has a higher potential to cause a fire or explosion.

St. Elmo's fire isn't actually fire, and nothing is burning. It's an electrostatic display which doesn't represent necessarily an increased temperature. In aircraft fueled with Jet A, the fuel tank generally contains a fuel/air mixture which is not conducive to a fire or explosion, especially from static discharges. This is a different matter with cut fuels such as Jet B or JP4. 100LL would be much more likely to ignite than Jet A.

I made a flight one night during a period of electrical activity, in a Seneca II. While I've seen St. Elmo's at higher altitudes often, I've not seen it often in light GA type aircraft. In this case, around eight or nine thousand feet, the propellers glowed blue green, and purplish and yellowish sparks spayed off the fuel caps, and other plastic non-conductive surfaces, including the windshield. Sparks danced around insidethe cockpit and across the windscreen. The propellers took on a neon caste, particularly around the tips, leaving two glowing circular arcs on either side of me. I quit looking outside and turned up the cockpit lights in case of a static discharge, but that didn't happen. It went away. My imagination certainly turned to the possibility of a fire or explosion with the active display of sparks spraying off the fuel caps, but nothing occured.

St. Elmos can signifiy ionization of the airflow around an aircraft, which can in turn form a pathway for lightening, or for a static discharge. With the presence of a discharge or lightening strike, the potential for a fire or explosion is escalated.

The USAF lost a C-130 and a KC-135 to lightning, as well as a F4 and a F16. Internationally a 707 was downed in 1963 and a 747 in 1976 as a result of the same, involving explosions or fires caused by the lightening. In each case, the aircraft was using a cut fuel.

There's never been a verified case of an explosion or fire in flight with Jet A, based on lightening or a static discharge. There have been many cases of engine flame-outs during such events, however, and other types of damage such as structural burns, blow-outs, melting, etc, do occur. I've had holes burned through flaps, elevators, and even propellers, and blow-outs in radomes (usually isolated to small semi-circular burns or blow-outs about a half inch to three quarters of an inche in diameter, in the shape of a thumb or crescent. I've also had melting on pitot tubes, stall/AoA vanes, etc.

Might have to call you on this last paragraph regarding lightening causing a catasprophic explosion on an aircraft. Back in 1963, Pan Am lost a B707-100 (N709PA) while it was holding at 5,000 prior to landing at either PHL or BWI, can't recall which. The left wing exploded when fuel vapors were ignited in the outer aux fuel tank vapor bay, thus causing the crash. The aircraft was fueled with Jet A but also contained a small amount of JP4 which obviously did not help matters, however, in the official accident report this mixture of fules was discounted and not found to be a contributing factor. A lot of new information has been generated over the last fourty years so one might assume that this new data would give some creedence to the fuel cuts used in this event. A greater amount of evidence was the suspicision that the lighten strike was a positve strike and thus significantly stronger.

I have both lightening strikes and massive discharges and it is frequently hard if not impossible to tell which has created the spectacular effects.

 

[avbug]

The 707 was fueled with Jet B mixture (cut fuel with gasoline, not straight kerosine); it was the one I mentioned in my comments. An Iranian B747 was lost during fuel tank explosion after a lightening strike, too...but was also using a cut fuel. A Lockheed Electra experienced an explosion following a lightening strike...cut fuel.

No history of aircraft exploding when fueled only with Jet A.

Static discharges and lightening strikes appear similiar in flight, though the damage left over usually is more localized in a lightning strike, whereas a static discharge usually has multiple points around the aircraft where damage has occured.

 

[Spooky 2]

I was probably editing my comments when you were sending me your thoughts on this subject. The fact that this cut fuel load was not a considered a factor in the final accident report is revealing for the time period in which the accident happened. The biggest change to operating procedures was the addition of static wicks to aircraft.

 

[avbug]

The Iranian B747 was also destroyed as a result of a failure of the aiframe and bonding to properly transfer the current. I've seen a lot of static wicks blown apart and/or melted when handling that electrical transfer; a small, but vital sacrifial part on the airframe.

I flew an airplane that experienced two static discharges of a significant nature, both of which did damage to the airframe. When the incidents occured, separated by a year, the company initially blamed me for operating too close to thunderstorms. I wasn't. I didn't find out until nearly a year after that, from someone in the training department, that they company had found the entire aircraft improperly electrically bonded. Every static wick and bonding surface had non-conductive paint beneath it. The company tried to hide that fact and settled for blaming the pilot.

 

[UALX727]

Dude, that's some messed-up stuff....

 

[Axel]

Regarding the "Pig Strike" report: From AVweb

Snake Strike

I read your article about flying snakes with interest (NewsWire, May 16). And I know the answer to everyone's subsequent question: Yes it's happened -- a mid-air snake-strike!
In one of the weirdest encounters I've ever heard of in aviation, a colleague of mine suffered a snake-strike flying a BAe-146 on final approach into Charles de Gaulle [Paris, France]. In this case, however, the hapless reptile wasn't truly flying itself; a heron had picked it up and made a flight path conflicting with the aircraft. At the last minute it panicked, turned away and dropped the snake, which struck the forward, left-hand side of the fuselage before being ingested through the #2 engine (this being deduced by the presence of the remains of the animal on the fuselage).
Consequently, the crew was forced to make a snake-strike report! And they say stranger stuff happens at sea.
Love reading AVflash.

 

[tomgoodman]

Hitting things

Heard a story about a "person strike" involving a skydiver and a light airplane. Supposedly, his chute got tangled in the elevator, causing a crash, but he cut loose, deployed his reserve chute, and survived.

 

[Lead Sled]

The most "compromised" I've ever been after hitting something involved insects. 30 years ago when I was flying the Grand Canyon, I flew through a swarm (flock, herd, gaggle, or large group) of migrating Monarch Butterflies on descent into Las Vegas. It was a mess - the oil coolers on both engines were plugged and the windshield was 95% smeared with butterfly guts.

LS

 

[Lead Sled]

Heard a story about a "person strike" involving a skydiver and a light airplane. Supposedly, his chute got tangled in the elevator, causing a crash, but he cut loose, deployed his reserve chute, and survived.

I remember reading something about an in-flight "cow strike" a few years ago. Something about a cow falling out of a Russian transport. I've also read of "fish strikes"

LS

 

[avbug]

We used to hit a lot of birds while spraying wheat in Kansas. I called them popcorn birds, because they wouldn't know we were coming until we were nearly on top of them...they'd rise out of the crop and the entire flock would end up impacting all over the airplane. It sounded like popcorn. We'd find them wrapped around spray booms, jammed inside the automatic flagman, and occasionally one would make it past the prop, strike the wire cuter on the front of the windshield, and either get cut in half (one half passing around each side of my face), or ride it up to the airscoop above the cockpit. When the bird entered the airscoop, it exploded, and the airscoop dumped down the back of my shirt...cockpit full of feathers, and shirt full of bird guts.

 

[Axel]

Ewwwuh!

You should have told that story to the guy who wanted to fly ag because it sounded like fun.

 

[Lead Sled]

There have been many examples of deadly birdstrikes. I remember the photo of a Turbo-Commander plunging nose first into one of Great Lakes. The most serious bird strike I ever witnessed was a Sabre 65 that rotated into a flock of seagulls on takeoff. The airplane was barely able to make it back around to the airport. Talk about Shreaded Tweet - both engines had to be replaced and the smell was nauseating - burnt feathers and seagull permeated the interior. The airplane sat (roasted) in the sun (it was summer in Utah) for a few days while they waited for a crew to come up from Phoenix to change both engines. After the engines were replaced they had to fly the airplane back to St. Louis un-pressurized to go through the environmental system. By that time, things had started to really get ripe.uke:
I gave the crew a large can of Ozium and watched them fly off into the sunset.

LS

 

[pilotyip]

How about the "Bird Strike" poster from the FAA. DA-20 Lorain County, Ohio, dual flame out at 35' due to bird ingestion, rode it dead stick into the ground, crew walked away unharmed. Tuff birds the DA-20. Co-pilot went back to Iraq; he felt it was safer

 

[avbug]

Iraqi birds just fight among themselves.

 

[belchfire]

"Well, sonny, there I was, hanging from the prop at 20 thousand feet with 4 Zeros above me and a Yamoto class battleship below me..."

 

[Axel]

There I was, flat on my back, one turnin' one burnin' and me hangin' on by the headset cable. Then we get the memo: "All pilots are to turn in communications gear immediately and forthwith."

Well, I'll tell ya, it was a sticky spot, but I'd seen worse...

 

[momalley81]

There I was, flat on my back, bleary-eyed from the wild night of margaritas and tequila shots. I couldn't quite remember what room I was in; or where my room was. Through the fog of hangover, I remembered arriving in Cabo that evening, and checking into the hotel, but after that it was all a blur of bikinis, booze and pool bar.

I rolled over and saw the heifer in bed with me, and realized I was in a REAL tight spot. She was about a deuce and a half. And I couldn't find my pants. Or remember what room was mine (was this it?)

THEN it got interesting when the chief pilot walked out of the shower and asked, "ready for round two?"

 

[Princedietrich]

Mayhap it's time to resurrect this thread for a bit.

Here's a good one where the moral of the story is that you always get what's coming to you, and it usually happens in the most hilarious and humiliating fashion. The summer of '99, I was working as a fueler and ramp-rat at Burke Lakefront airport in Cleveland. The job paid the bills because flight instructing sure wasn't cutting it. There were four of us on the 7 to 3 shift: myself, a new trainee named Kevin, a veteran fueler named Steve-o, and the line manager Rob.

Rob was one of those types that believed that he was the be all and end all, and that he shouldn't be bothered with trivial things like... work. He was also very quick to point out your flaws and would not even have the decency to look in your direction when he refused your desperate pleadings for help with that ramp full of biz jets during game 6 of the playoffs and the Indians were winning. I'd locked horns with him a time or two, and for the record yes I really do think he needs to have a boot broken off in his arse (long story).

Anywhat, I was in the hangar doing some upkeep on one of the tugs. Kevin and Rob were squatting beneath a Falcon 900 owned by a very eccentric and somewhat senile Cleveland bazillionaire (he was an owner of the San Jose Sharks at the time, and had the team logo painted on the tail). This particular Falcon had two distinct "chambers" inside the cabin. The front was where the galley and fore lav were, and was the place that the crew got to call home on extended trips. The rear was the private stateroom and aft lav for the owner, and let me just say that his taste in movies was rather interesting. I know this because after one flight he'd forgotten to put away his collection of Swedish bondage massage films. Rob was in the process of showing Kevin how to work the Crapillac Poop-DeVille, our affectionate name for the lav cart, by servicing the aft lav.

I'd serviced the aft lav on this plane before, and I knew that the cap for the dump valve was a bit gimpy. It took some doing to get it to come off because some bozo in the past at some other FBO had cross-threaded it. Rob popped open the access door and wrestled with the cap trying to get it off. It wouldn't budge no matter how he twisted and heaved and argued with it, so he improvised. He went to the nearby tool rack and got a flat head screwdriver and a rubber mallet, the proceeded to beat the cap into submission to by trying to chisel and pry it off. I put down my quart of oil and sat on the tug, eagerly awaiting the show that I knew was coming soon.

The cap finally budged enough to come loose, and now it could be turned by hand. Rob happened to be directly under the thing and started loosening it. He looked up at Kevin and uttered the immortal words "Now, make sure you're not directly under this thing when you take the cap off. There might be a suprise waiting behind it." Kevin nodded, and with a final twist of the wrist Rob freed the valve cap.

Now, I'm guessing that all of that banging and prying and chiseling with the screwdriver and mallet was not well received by the innards of the lav dumping system. Apparently, the vibrations and the impacts were enough to knock the dump valve open. Rob was looking up at the panel to see what he was doing, and he was greeted right in the face by 4 and a half gallons of chunky bluish-green foulness that I don't really care to imagine. Kevin got off easy because his shoes were the only casualties, but Rob was drenched from head to toe in the stuff. He got up slowly, like a zombie rising from the grave in a George Romero flick, and started walking very stiffly through the hangar. He barked an order at me to open the door for him and follow him to the janitor closet where I proceeded to dump bleach and hot water on him to wash off the filth. He then excused himself to go home and get changed, and we didn't see him again the rest of the day. Steve-o missed the entire crap-tastrophe because he was on the ramp fueling a jet, but he shared a hearty laugh with us as he helped us clean up the mess.

True, it was a filthy mess, but it came to be in such a rewarding fashion for the three of us.