Anyone with knowledge about embeddeds care to comment? Thanks-L.

-- Lucy (windsng@123.com), February 02, 2000

Answers

The $64,000 Question. MY feeling is not, but I will defer to folk like WW who has some experience in the building of these critters and perhaps Cherri who might or not have some embedded experience in aerospace (I don't rememeber).

CHuck

-- Chuck, a night driver (rienzoo@en.com), February 02, 2000.

Lucy:

It's really early even to assume that the stabilizer trim was the one and only cause of the problem. We'll know more once they get the flight data recorders.

The stabilizer trim is controlled either by the autopilot or manually by the pilots through electric servomotors. It's highly unlikely that the autopilot or computer were the problem since the pilots can override the system and control the trim tabs directly. There has been an airworthiness directive out for about 18 months concerning possible corrosion in the trim tab connectors so it's also possible that there was a mechanical failure of the connection.

The MD-80 series has been extremely reliable in service worldwide but aviation is always a risky business.

-- Jim Cooke (JJCooke@yahoo.com), February 02, 2000.

If these planes are using a GMT time reference, the time that the one in California crashed would have been just shortly after the clock rolled over to February 1. It could be that some of the embedded coding was not written to deal with a leap year in a year that ends in "00". This type of problem could happen in all planes with the same type of systems. My guess would be that this is the first time this plane in Arizona has taken off in the month of February. If that is the case, we may have a viable working theory, and all similar aircraft should be grounded.

-- Hawk (flyin@high.again), February 02, 2000.

Hawk Just posted this a few threads down Hope you don't mind the cross post Hawk.

If these planes are using a GMT time reference, the time that the one in California crashed would have been just shortly after the clock rolled over to February 1. It could be that some of the embedded coding was not written to deal with a leap year in a year that ends in "00". This type of problem could happen in all planes with the same type of systems. My guess would be that this is the first time this plane in Arizona has taken off in the month of February. If that is the case, we may have a viable working theory, and all similar aircraft should be grounded.

-- Hawk (flyin@high.again), February 02, 2000.

-- Johnny (jljtm@bellsouth.net), February 02, 2000.

As I remember from my flying days, trim tabs are controlled by a cable/pully system, or by hydraulics. I don't believe embededs would have anything to do with it.

-- RPGman (tripix@olypen.com), February 02, 2000.

Ooops, thanks Johnny!

Does anyone have connections at American Airlines that could find out if the flight in Arizona was the first time that plane took off in the month of February?

-- Hawk (flyin@high.again), February 02, 2000.

Not very likely in my opinion.

Too many similar aircraft flying without problems. (Yes - I recognize that different versions of the "same" embedded controller respond differently to date sensivity.)

It does not invalidate the concept, jus tmakes it much less likely to be the problems....that is, if it can be shown that the controller DID cause the problem, the presence or absence of any date input related to year 2000, might not not cause the control loss of the tail surfaces.

For example, a few years ago, a mechanical engine failure wiped out the hydraulic lines in the tail of a commercial jet. The controller was not at fault, since there was no "system" to control, nor any hydraulic fluid in the system to move the control surfaces.....

-- Robert A. Cook, PE (Marietta, GA) (cook.r@csaatl.com), February 02, 2000.

Sorry Hawk

I'm going out on a limb here and posting only something I barely remember.

I recall a conversation with a " aviation expert" on the tube the other day and what I remember him saying was that these MD-80's were aircraft that conterfit parts were abundant for.

-- Johnny (jljtm@bellsouth.net), February 02, 2000.

Sorry for what?

I was going to say that they don't always use exactly the same parts in these planes. Maybe some parts have problems, and some don't.

-- Hawk (flyin@high.again), February 02, 2000.

Let me chime in on this. Embedded aren't going to be part of this situation, because MD-80s are not fly by wire aircraft. They're the a combination of hydraulics to move the stabilizor and electic switches and motors for the trim system. Not an embedded device in sight.

But Johnny has hit on something with the counterfit (non-approved) parts issue. A few years back even the FAA was saying that it was only a matter of time before a major crash was caused by one. This might be that first time.

It seems that since licensed production of MD-80s & MD-90s started in China, non-approved parts have been rapidly apprearing in the spare parts industry. This is a serious problem because it involves lots of falsified documentation, not just the box the part comes in. Awfully sophisticated, not a fly by night operation, you know.

There was a spate of improperly reconditioned parts being passed off as good parts back in the eighties that opened FAA's eyes to this issue. That started the current documentation requirements for approved parts. It's all traceable back to the lowest level employee who handles that part during its manufacture and any repair or reconditioning.

If you work with parts going into a passenger aircraft you have to do everything but give blood to be able to touch the part (including pee in the bottle on a regular basis). If this is a non-approved part related crash, it means that somebody has managed to create a counterfeit information bank to back up their fake parts.

Or they're a backdoor operation of a legitimate activity. Like maybe the licensed parts makers in China sending Quality Control rejects out the back door as good spare parts. That's worrisome 'cause it means a very large and sophisticated organization is involved. The People's Liberation Fake Aircraft Parts Company, perhaps?

WW

-- Wildweasel (vtmldm@epix.net), February 02, 2000.

Hey there-Hawk-You better stick to politics and oil problems because your posting up above shows you are up to your eyebrows in warm brown bull poopy-doo.

-- Liberal Hater (liberty@bell.com), February 02, 2000.

Hawk,

First of all, leap year problems will not be evident until MARCH 1, 2000.

Second, the leap year rule is usually coded as "if year divisible by 4, year is a leap year". 2000 IS divisible by 4, so no problem.

The problem occurs in algorithms that try to calculate 1900 dates (a smaller percentage), which was not a leap year. The proper algorithm is

(a) If the number of the year is divisible by 4 then the year is a Leap Year, except

(b) If the number of the year ends in 00 then the year is not a leap year; however

(c) If the number of the year ends in 00 and the year is divisible by 400 the year is a Leap Year.

That said, the problems with the stabilizers is still very suspect...

-- (@ .), February 02, 2000.

Re: Chinese spare parts and quality control.

Recently the Big Three automakers instituted their quality program called QS 9000 which is built on ISO 9000 but with more visibility, procedures, documentation and site audits required. QS 9000 divides suppliers into four Tiers. Tier 1 is for criticial materials, parts or services that directly affects the quality of the automobile.

Exterior galvanized sheet for the stamping plant is one in which I have a working knowledge.

I am told that in China, the ISO certifications are basically for sale and do not carry the same commitment and meaning as here in the USA or western trading partners. This is why there are no Chinese steel or parts in the original equipment for cars made in North America. I am told that in a QS 9000 audit, the car company rep will deduct points from your score if he sees a supplier using parts or materials from China.

There are Chinese product in steelplants and occassionally they perform as well as US made parts. They just do not have the same consistency and reliability.

-- Bill P (porterwn@one.net), February 02, 2000.

Liberal Hater,

I don't think we have room for hate on this forum. Why don't you do us a favor and get the fuck out of here, asshole.

-- Hawk (flyin@high.again), February 02, 2000.

Hey there-Hawk- I didn't say I hated you "big boy". In fact you're my favorite to pick on. I have noticed though that you can dish it out but you have some difficulty taking it. Probably a bad hair day!

-- Liberal Hater (liberty@bell.com), February 02, 2000.

Hawk, don't pay any attention to asshole haters.

Open-minded yourdonites do welcome your posts.

Take care

-- George (jvilches@sminter.com.ar), February 02, 2000.

no one in this thread has mentioned the fact that another M-80 had some questionable stabilizer problems today and had to return to the airport. Does anyone remember last month when 3 separate planes, i think they were boeings, don't remember model but they were all the same, all developed the same problem on the same day with (if i remember correctly) the landing gear? seems rather coincidental.

-- boop (leafyspurge@hotmail.com), February 02, 2000.

737s British Airways, and Concordes, BA. Can't reacll the parcticular problem but was reproted as electronic systems in all cases, do believe.

-- Squirrel Hunter (nuts@upina.cellrelaytower), February 02, 2000.

Re GMT: the beautiful LASCO is still running a 100 century date. Maybe some of the UNIX people could advised if this might cause a problem with interfacing systems running on other time expression.

-- mike in houston (mmorris67@hotmail.com), February 02, 2000.

boop,

Three planes were 737 series aircraft in Norway. Report indicated two were in the air (over different parts of the country), at what appeared to be the same time, declaring emergencies, and landing safely. One with similar problem, was later found at the gate.

-- (snowleopard6@webtv.net), February 03, 2000.

Just heard on news flight recorder box located and on it's way to Washington for analysis.So we'll know something soon enough i guess.

-- JM (give_us@break.com), February 03, 2000.