Saturday, October 07, 2006

May 12th, 2005 - a day I'll never forget...


I wrote this soon after it happened, and ran across it recently in my files...

The plan was to fly down from Kansas to South Carolina to see Darrell graduate from drill sergeant school. Nothing went according to plan.

The first step was getting to the Manhattan airport for a US Airways flight at 5:10pm Thursday. A friend of mine dropped me off a bit early as she had a meeting at 3:30, but that was fine.

Soon after they dropped me off, a huge thunderstorm hit. I wasn’t too worried about missing the flight - these thunderstorms move fast and I had two hours before the flight was supposed to take off. Well, it didn’t ease up much. 5:10 comes and goes. I didn’t end up getting off the ground until probably 6:45.

Since the Manhattan airport is so small, the lady at the ticket counter is also the lady that does baggage and this-and-that and who knows what else. So she wasn’t around when I wanted to see about my connecting flight in Kansas City. While I was waiting, I call up the airline’s customer service desk. I explain the situation to her, “The flight I’m supposed to be on right now is delayed due to weather so I will miss my connecting flight. Can you help me get on different flights?” Her answer: “what day is the flight scheduled for?” Uh, TODAY???! The flight I am supposed to be on RIGHT NOW!!

Obviously that wasn’t going to get me anywhere. She keeps asking a bunch of similarly stupid questions and ends up telling me that I need to talk to the ticket counter. She didn’t care that there wasn’t anyone AT the ticket counter. Whatever.

So finally the lady shows up and starts to reconnect me, but just as she gets started, the pilot pops his head in and says that he just got clearance to take off. She had to get a bunch of other stuff done, so I just decided to do what I needed to do at the Kansas City ticket counter.

As we’re going through security, I was informed that I was the lucky “randomly chosen” passenger to be fully screened. (One way tickets will do that to ya’.) Lovely. Not a huge deal - I don’t freak out when people touch me, but still a pain. We finally all get on the plane, all eight of us, and the pilots start their preflight checks. They get that done and we’re off. This was a tiny plane - only seated 20 or so passengers, only window seats, propellers and everything. Perfect for turbulence! The flight should only be about 30 minutes, but we had to divert around some nasty stuff in the air so it ended up being about 50 minutes. Even WITH diverting around the messy stuff, it still was quite a bumpy ride.

Now, I LOVE turbulence, so I was having fun. The lady across the aisle from me wasn’t, however. Her hands were gripping the arm rests so much I thought she’d pull them off! The plane was bouncing all over the place. Never bad enough to get worried. Well, I wasn’t worried, but the lady across from me was.

We landed in the middle of a horrible downpour. The pilot told us during the taxi that the wind was gusting at 40 miles per hour. I wasn’t sure that we’d come down ON the runway, there was such a cross breeze! Since we were in such a small plane, we had to walk through the rain to get to the terminal. By this time, the Kansas City airport was shut down due to weather, so we just waited in the plane until the worst of it let up. Once it did, they fired up the plane again and got as close as possible so we’d only get half-way drenched instead of all the way drenched.

Once in the terminal, I made my way over to the check-in counter to get hooked up with new connections. She found me a Midwest flight to DC, then a connection from DC straight to Columbia. It was going to be close, but still doable. The flight arrival time to Columbia was 11am and D’s graduation was at 1pm. No problem!

Luckily I didn’t check any baggage, so I didn’t have to worry about where my suitcase ended up. I went upstairs to find the Midwest gates. I found where I needed to go and got in the security line, only to find out that again, I was the lucky one to be fully screened. Ok, so we go through the whole thing again.

As I’m sitting down, the lady at the check-in counter says over the loudspeaker that the plane we’re supposed to get on is late arriving because of the weather. They are circling Omaha until the weather clears enough here, then they’ll be allowed to finish the flight to KC. The delay will be at least another half-hour. Ok, I’m already late. No biggie. My layover in DC is about 7 or 8 hours, so I don’t care how long it takes to get on this flight, as long as I do get on the flight.

I needed to go to the bathroom, so although I know I’ll have to be searched again as I go through security (special note on my boarding pass), off I go to find the bathroom. I do my business and walk around a bit. When it gets close to the time the plane was supposed to land, I go through security again. Almost as soon as I sit down, she announces that the plane got clearance to head south but because it had to circle so long, they needed to land in Omaha and get more fuel. Another delay.

By this time, I’m super hungry, so I leave the area again to find some food. Just as I get to the food area, they’re closing up!! Un-freaking-believable. I brought some cookies for Darrell, so I dive into those. Sorry, D. Since there is nothing else to do but wait, I go through security again (I know the routine by now) and sit down. The next announcement gives us a final boarding time of about an hour and a half later.

I have a friend that lives in KC, so I gave him a call and he agreed to come over and chat for a bit. Once he got there, I had to leave the secured area again. We talked for about 45 minutes when they finally started boarding the flight to DC. So, through the security again, another pat-down by the friendly security people, and finally onto the plane. I ended up getting a great seat. Midwest is awesome! Huge leather seats, lots of legroom, nice. I was in 4B, an aisle. I prefer a window, but they were all taken.

We get pushed back from the gate and get in line to take off. About this time, the next wave of thunderstorms rolls in. It was wicked bad. Lightning everywhere! The pilot comes over the loudspeaker to tell us that he and his copilot have decided to wait out the worst of it. He says that they have clearance to take off, and other planes were, but that he felt more comfortable waiting awhile. Okay by me! I’ve already been through a bunch of turbulence already through this storm. And like I said, my layover was really long in DC, so I just need to get there - don’t care what time.

About 45 minutes later, the worst of the storm has gone by and we take off. No problems during take off. My row-mate was a 12 year old boy. His grandmother was in the seat in front of him; his aunts were two rows back. He’d flown before, but I could tell he wasn’t too thrilled with the idea. Ten or fifteen minutes into the flight we started to feel some turbulence. Nothing too bad - we were ahead of the storm at this point. I think.

The turbulence went from not bad to really bad quickly though. Did anyone hear of Midwest flight 490? Well, that’s the flight I was currently on. If not, after you read the rest of the story, do a google news search on it. Whew!

Anyway, let me finish the story first. For about 30 minutes or so (we never did agree on how long, some said 20 minutes, others said 45), we felt like we were on that roller coaster at Disney World called Tower of Terror - the elevator one where you don’t know when you’re going up or down, or how long. The plane dropped elevation so fast that we (and our bags) were weightless for stretches of ten seconds or longer. Then we’d pull up so fast that the skin on our cheeks pulled back - serious G forces! It seemed to me that the pilot wanted/needed some altitude because every time we’d fall, he’d pull back as hard as he could to make up altitude!!

By this time, passengers all over the plane had their barf-bags out. I was queasy, but not to that point. The guy across the aisle from me was extremely pale and throwing up often. It was pretty bad - remember, I LOVE turbulence, but this was far beyond what anyone would call turbulence!

After it was obvious that something was wrong, some of the mothers started freaking out. A lady in front of me was flying with her two boys (around 8 and 10 years old). She was holding their hands, one across the aisle, and telling them how much she loved them. A row behind me, the mother of a two year old was twisted sideways, holding her little boy with as much of her as she could while still keeping them both belted in. The two mothers both had tears streaming down their faces, scared to death, but really trying to hold it together so as to not freak out their boys even more.

This goes on for what seams like forever. It’s totally black outside, clouds everywhere, so we can’t see where the ground is. I’m pretty sure that we were still ahead of the storm, but the newspaper articles say otherwise. Although, those same articles got lots of details wrong, so I’m not buying a word they say.

Finally the pilot comes on and says that we’re going to be making an emergency landing in Missouri. No big deal, I’m thinking, we need to land to get out of the storm. No worries. Then the flight attendants start telling us that we need to brace ourselves in the crash-landing position!! I’m still amazed that at this point, no one freaked out. The whole plane was calm, the flight attendants walked up and down the aisles showing everyone how to do it (I think the pilots just coasted/glided as much as possible during this so they could walk the aisles, there is NO WAY they’d have been able to otherwise while the pilot was trying to maintain/regain elevation). The flight attendants told us that we weren’t planning to crash, but that we were in a true emergency and we needed to follow standard procedure. Not their exact words, but that was the idea they were getting across. Ok, I’m a little freaked out now - this isn’t just an emergency because we’re landing at an unanticipated airport, this is the real thing!!

After the flight attendants buckle in, the plane goes back to its ups and downs. Once we get close, the flight attendants start yelling, “brace!” every five seconds or so until we landed. I could hear some people muttering, either crying or praying or whatever, but not loud - not completely losing it.

We landed without even a bump. We slowed down super fast, but we found out later that was due to a shorter runway than that aircraft normally uses. We landed at an unattended airport in Kirksville, MO. Once we came to a complete stop, the pilot came out of the cockpit and told us that he wasn’t sure what happened or why we had gone through what we had gone through, but that at times, they had lost control of the aircraft! We never did get any more details directly from him, but over the next day or so, there was a lot of, “well I heard someone say that they overheard the pilot say”. One of those rumors - which I believe were factual, not just stuff people made up: the plane could not turn (the pilots wanted to turn around and land at KC soon after take off, but the airplane would not turn; Kirksville was in the direct path to DC so we were able to land safely).

I’m hoping to find the official NTSB report online in the future. I’m curious as to what actually DID happen.

Anyway, this was a tiny airport. They didn’t have stairs for the big planes, so while the crew was trying to figure out what to do next, the firefighters tried to find a way to get us off the plane. I’m sure they could have used the inflatable ramp thingies, but they’re probably super expensive. We were totally safe on board, so there was no hurry to get us off.

About an hour later (they were handing out drinks during this time), they found a construction cherry-picker thing to get us off. Not one of those huge ones with a long arm like the electric company uses, just an up and down thing. They’d load it up with six or eight people, bring it down and unload, go up again and get more people, etc. The nearby college volunteered their campus cops, a bunch of students, and every school van they could get their hands on. These vans drove us from the plane to the terminal.

There were 76 of us on the plane (a Boeing 717 that seated 88, with four crew members) so finding lodging for the night was a bit of work. We ended up getting split up into about six groups to different motels in Kirksville. They may have been a tiny podunk town in the middle of nowhere, but they volunteered what they had. The people were super nice!

The school vans took each group to their respective hotel, then picked us up again in the morning. On our way back to the airport, the driver told us that Kirksville had two fatal aircraft landings in October 2004, so the town had plenty of disaster practice. That’s why our event was so nicely and efficiently handled! Also, the night before during a thunderstorm, lightning hit a bar downtown and completely burned the place down! We couldn’t wait to get out of that town - too much dangerous stuff going on. Midwest arranged for some coach busses to take us back to KC. It was about a 3.5 hour drive. Once there, they arranged for each passenger to either keep going on their trip, or paid for a rental car in case people wanted to drive. A few did decide to drive, either home or onto DC. One guy said he’d never fly Midwest or a Boeing 717 again. Whatever. It’s still way safer to fly than to drive all the way to DC, but that’s how he felt. Okay.

Midwest sent me back over to US Airways to get to Columbia. By the time I got my tickets, Darrell’s graduation was over. I decided to go anyway, spend some time with him, take a look around at some houses, and drive back as originally planned. US Airways sent me through Philadelphia, so I called my mom to meet me there during the hour layover. She walked me to the next terminal. It was cool to see her.

The rest of the trip was uneventful. I got "randomly" selected AGAIN on my next flight, although finally NOT the very last one. (Random, my butt - I'm the least of their worries, I had a freakin' top secret clearance for cryin' out loud!!!) The flight from KC to Philly had some turbulence, but just the boring normal kind. The flight from Philly to Columbia was on a tiny plane (jet though, not propeller) and the line to take off was super long so I ended up talking to the flight attendant for about 45 minutes telling him all about the adventure. By this time, I’d told the story a bunch of times, to Mom, Darrell, Sam... Hahaha. Plus, all the passengers could talk about during all the waiting we had to do was the flight - it was cool to get so many other people’s experiences and feelings about what had happened. A few of the news stories said stuff like “we all thought we were going to die,” (uh, I didn’t), “we thought we were doomed,” (uh, I didn’t), and other crazy stuff, but most of the people I talked to were of the same opinion I was - while we certainly could have been killed, we didn’t think we were going to crash and die.

Everyone agreed, though, that the flight crew did an amazing job. The pilots got us through some terrible conditions (still not sure if it was weather related or mechanical) and landed us safely. The flight attendants remained calm and worked out all the post-landing details while keeping us up-to-date to what was going to happen next. I will certainly fly Midwest again and I have no problems flying a Boeing 717 again. I did get the slightest bit nervous when the bus pulled into the KC airport, knowing that I was about to fly again, but it didn’t last long. It’s still way safer to fly and I love to fly anyway. While I missed Darrell’s graduation, I’m still glad I made the trip, even with all the unexpected adventure!

So, that’s my story. Wish I could tell you that I made it up. But, I didn’t! I kept thinking throughout the whole thing - I am so glad Justin wasn’t there, and it’s a good thing this happened to me instead of my friend Steph (she doesn’t like flying)!!!

And the preliminary NTSB report:

NTSB Identification: NYC05MA083
Scheduled 14 CFR Part 121: Air Carrier operation of Midwest Airlines
Incident occurred Thursday, May 12, 2005 in Union Star, MO
Aircraft: Boeing 717-200, registration: N910ME
Injuries: 80 Uninjured.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.
On May 12, 2005, about 2321 central daylight time, a Boeing 717-200, N910ME, operated by Midwest Airlines Inc., as flight 490, experienced a loss of pitch control while climbing through 23,000 feet, over Union Star, Missouri. The flightcrew declared an emergency, and the airplane was subsequently recovered at an altitude of 13,000 feet. The airplane diverted to Kirksville, Missouri, and landed uneventfully. There were no injuries to the two certificated airline transport pilots, two flight attendants, and 76 passengers. Night instrument meteorological conditions prevailed for the flight that departed from Kansas City, Missouri, about 2308, destined for the Ronald Reagan National Airport, Washington, District of Columbia. An instrument flight rules flight plan was filed for the scheduled domestic flight conducted under 14 CFR Part 121.
According to the captain, the flight sequence for the day had originated from Los Angeles, California, and was scheduled to land at Kansas City. Due to weather at Kansas City, the flightcrew diverted to Omaha, Nebraska, where additional fuel was obtained and a further evaluation of the weather conditions could be made.
After reviewing the weather, the flight departed for Kansas City at 2100, and proceeded uneventfully, landing at 2146.
While in the company operations area, at Kansas City, the captain was briefed by company dispatch personnel regarding significant weather that was moving from west to east prior to the departure for Washington. The captain also noted the weather on a display screen that was located in the operations area.
As the airplane was taxied for departure at 2231, the captain elected to delay the takeoff, and wait for the weather pass further to the east. Once the weather past, and the flightcrew received a "ride report" from a previous departing airplane, the flight departed from runway 1L.
As the airplane climbed on a northerly heading, the captain observed a green area on the cockpit radar screen, "indicating the presence of rain." Areas of yellow were also observed on the screen, at a distance of 20 miles or more to the east. Once the captain determined that the flight was sufficiently clear of the weather, he requested a turn to the east. The air traffic controller subsequently cleared the flight onto a 060-degree heading and to an altitude of FL270.
As the airplane turned to the assigned heading, the captain observed a master caution light illuminate on the glareshield, and a "config" on the center console. The captain then observed that a "rudder limit fail" alert was being projected on the engine and alerting display (EAD). As the captain was about to call for the quick reference handbook (QRH), the airplane pitched down abruptly and the autopilot disconnected. Both pilots placed their hands on the control yokes in an attempt to arrest the descent. The captain noted that the airspeed was increasing rapidly and that they were losing altitude. The airplane then began an uncommanded climb, which was followed by a series of uncommanded descents and climbs, which lasted for several minutes.
After regaining control of the airplane, the flightcrew diverted to the Kirksville Regional Airport, and landed uneventfully on runway 18.
Examination of the airplane's exterior revealed that the oil filler door on the right engine nacelle was open, and evidence of a lightning strike exit hole was visible on the top surface of the tail cone. Further examination of the exterior did not reveal any other lightning holes.
Functionality testing of the airplane's flight control systems and avionics were conducted after the incident, with no abnormalities noted except for a disconnect of the flight control columns.
The airplane was equipped with a cockpit voice recorder (CVR), and a digital flight data recorder (DFDR). Both recorders were transported to the Safety Board's Office of Research and Engineering for further examination.
Several other computer components were removed from the airplane for further examination and extraction of retained data.
The reported weather at Kansas City, at 2317, included 8 miles visibility; light rain and thunderstorms; ceiling 3,900 feet overcast, with cumulonimbus clouds; temperature 64 degrees F; dew point 64 degrees F; altimeter 29.99 inches Hg. The report also noted that frequent lighting was observed, and the thunderstorm activity was moving east.

I just did a google search and found this. Yikes!!

And the NTSB "Probable Cause" report


Originally posted: Saturday July 29, 2006 - 01:32pm

11 comments:

  1. I came across your blog post during a google search on the Midwest Airlines incident in Kirskville. I was a Midwest Airlines flight dispatcher at the time of your incident (but was not working your particular flight at the time). During our training, we reviewed some of the details of your flight's incident. I don't say this lightly, but you were very fortunate that day. I knew both of your pilots on a first-name basis and am so thankful that things turned out as they did!

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  2. Yes, me too!

    Anything you're allowed to tell me?

    Thanks for the comment. It's rather surreal thinking about it now.

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  3. And Jim, if you see either of them again, thank them for me?

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  4. New discoveries:

    http://www.alpa.org/portals/alpa/pressroom/NTSBSubm/2005-5-12_MEA.pdf

    http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=mro&id=news/ntsb9147.xml&headline=NTSB%20Reiterates%20Automated%20Air%20Data%20Sensor%20Heating%20Recommendation

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  5. And the archived story from the local paper:

    http://nl.newsbank.com/nl-search/we/Archives?p_action=doc&p_docid=12A060C45D8C4520&p_docnum=1&p_theme=gatehouse&s_site=KDEB&p_product=KDEB

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  6. I was on this flight with you 15 years ago and came across this blog post while searching for the NTSB entry (their system and my bookmark changed). Your account of it is really good and 100% consistent with my experience and memories. I have flown more than 2 million miles and this was the worst experience of my flying career. Hats off to the crew and the amazing volunteers in Kirksville for all that they did to help us!

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  7. I typed this up a day or three after it happened, so memories were very fresh.

    Just did another Google search - from https://www.skybrary.aero/index.php/B712,_en-route,_Union_Star_MO_USA,_2005

    On 12 May 2005, a Boeing 717 crew climbed in night IMC without selecting the appropriate anti-icing systems on and as a result lost control. The non-standard crew response led to an eight minute period of pitch excursions which occurred over a 13,000 feet height band at recorded ground speeds between 290 and 552 knots prior to eventual recovery and included a split in control columns some two minutes into the upset. The Investigation concluded that the aircraft had been fully serviceable with all deviations from normal flight initiated or exacerbated by the control inputs of the flight crew.

    More details on the page. Only eight minutes, huh? Felt a lot longer than that.

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  8. Details: http://avherald.com/h?article=41289e84

    A Midwest Airlines Boeing 717-200, registration N910ME performing flight YX-490 from Kansas City,MO to Washington National,DC (USA) with 76 passengers and 4 crew, experienced a series of wild pitch oscillations while climbing through FL190. The indicated airspeed subsequently fluctuated between 52 and 460 KIAS (ground speed between 290 and 552 knots), the altitude between 10600 and 23300 feet. The crew managed to regain control after several oscillations and diverted to Kirksville,MO, where the airplane landed safely. No injuries had occured during the upset.

    The National Transportation Safety Board (NTSB) just released their factual report suggesting - the formal conclusion of the probable cause not yet done -, that the wild pitch oscillations were the result of a lightning strike causing the air data (pitot) heat system switch to fail resulting in most of the pitots icing up and thus producing unreliable air speed data.

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  9. The captain was pilot flying. A strong thunderstorm front was just passing Kansas City as the airplane was scheduled to depart. The captain therefore decided to delay departure until the weather had passed to the east. Another flight gave a "ride report" before the captain elected to depart, the weather system now being 25nm east of the airport. After takeoff the airplane turned onto a heading of 010 degrees taking the airplane away from the weather system. The airborne weather radar showed only green areas ahead of the airplane despite adjusting radar pitch and tilt. The airplane was steered by the autopilot, the vertical profile being controlled by the flight management system. The airplane entered IMC conditions, but no turbulence was observed during the entire departure. The captain turned to heading 060, the flight was cleared to climb to FL270 and switch frequencies.

    Ground based weather radar information showed the airplane's location within a large area of strong echos indicating thunderstorms and rain up to 42000 feet.

    As the airplane climbed through 19000 feet, the master caution light and the config cue switch illuminated, the EICAS secondary screen changed from the engine display to the configuration display. 12 seconds later the autopilot disconnected. Many parameters associated with various flight systems and modes recorded by the flight data recorder toggled around that time. The captain noticed a "RUDDER LIM FAIL" message displayed on the secondary EICAS screen.

    Just as he wanted the first officer to retrieve the Quick Reference Handbook (QRH) to work the according procedures, the airplane began to pitch down. The first officer recalled, that the pitch angle reached more than 20 degrees nose down. The captain recalled, that he heard the autopilot disconnect wailer. The captain was still pilot flying, but the first officer began to assist at the controls. The airplane settled in a steep dive, that the first officer felt was almost beyond recovery. The airplane did not respond to control inputs, the controls felt very heavy. The captain reported, that there was little response to the control inputs and all of the sudden a lot of response, the first officer recalled a loss of altitude of at least 5000 feet.

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  10. The airplane then pitched sharply up despite both crew now pushing the yoke to the most forward position in order to keep the nose in a normal attitude. The airspeed decreased to about 190 KIAS, at which point the first officer advanced throttle levers to about three quarters of travel (about 80% N1). The power levers felt normal. Although the captain managed to keep wings level, he was unable to regain altitude control.

    The airplane pitched down again and entered another dive, the first officer now took control over ("I have the airplane" followed by the captain's "okay"). The first officer now handled the controls with the assistance of the captain and managed to regain control of the airplane. The captain continued to manage the flight controls until he began to communicate with air traffic control, at which point he relinquished controls to the first officer without a "formal" transition of controls.

    The first officer said later, that the airspeed went below stall speeds and above overspeed during the recovery. The flight data recorder showed airspeeds between 52 and 460 KIAS. The various airspeed indications (primary captain's airspeed, standby airspeed indication) began to disagree.

    Following the recovery of the airplane the crew noticed a "COLUMN DIS" (captain's and first officer's flight controls disconnected) message on their EICAS. The flight data recorder showed, that the differential control forces applied by captain and first officer during the recovery exceeded the design values, at which the control columns were intended to disconnect (in order to free one set of controls in case of the blockage of the other).

    The captain elected to divert to Kirksville feeling, the airplane needed to get onto the ground as quickly as possible. The autopilot was reengaged with autothrottle disengaged until final approach. The first officer performed a manual landing with the captain operating spoilers and throttles.

    The cockpit voice recorder revealed, that the captain announced "rudder limiter fault" followed by the autopilot disconnect aural signal, then both pilots called "down, down, down" several times. The captain declared emergency to air traffic control, 2 seconds later the first officer declared emergency to air traffic control, and both crew repeated the emergency calls several times. The overspeed aural signal was recorded later, both pilots calling "up, up, up" several times following again by "down, down, down" several times.

    Four minutes after the start of the upset the captain said "get the ice on" followed by "ice protection, ice protection". A sound like the click of a switch was recorded, shortly thereafter the captain advised ATC of the column disconnect and that they did not have any elevator control. Several more cycles of "up, up, up" and "down, down, down" followed. 8 minutes after the upset began, the crew started the diversion to Kirksville. The captain reported to ATC 14 minutes after the begin of the upset, that the airplane was back under control.

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  11. Examination by the NTSB revealed two lightning strike attach points, one at the aft edge of the tail cone and one at the lower aft edge of the #3 VHF communication antenna. No further evidence of lightning was found, no parts were missing or damaged. The bonding strap providing electrical connectivity between fuselage and tail cone was intact and showed no heat damage or discoloration.

    The flight controls system showed no fault, except for the disconnected control columns. The disconnect alert was found working properly.

    The rudder system showed no fault.

    The air data heat system was tested without finding a fault.

    When the Air Data Heat switch underwent a 100 cycles switch test however, it was noticed that the electrical resistance between pins 6 and 7 was 116 milliohms although the specification by the manufacturer of the switch requires a value below 25 milliohms.

    During the first test cycle the resistance between pins 9 and 11 was greater than 1 Ohm (in other words, the contacts did not close). The single encounter did not repeat in the following 100 cycles of testing.

    The switch was x-rayed and subsequencly disassembled for examination. Evidence of arcing was found as well as lightly peened contact surfaces.

    The manufacturer of the switch provided three possible scenarios resulting from malfunction of the various poles of the switches, one scenario resulting in the loss of the rudder limiter pitot heat. This, in a NTSB test, led to the subsequent failure of the rudder limiter pitot and finally ended in a "RUDDER LIM FAIL" message.

    A simulation test regarding airplane performance revealed, that the air speed data off the flight data recorder had gross differences to the calculated simulation speeds. "The results of the simulation study indicated that the FDR airspeed data contained intermittent streams of anomalous data", the NTSB wrote.

    The full factual report is available at: http://www.ntsb.gov/ntsb/brief2.asp?ev_id=20050523X00653&ntsbno=NYC05MA083&akey=1

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