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MarcoT
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 4:07 am

Quoting OPNLguy (Reply 198):
What I mean was does anyone know for sure that the Kenya -800 was a SFP model?

I don't know, but the serial number (35069, according to aviation-safety,net) apparently does not compare in the list of the affected serial numbers from the Emergency AD 2007-06-52

(link by hand: Regulatory_and_Guidance_Library/rgAD.nsf/0/D08E486777976E508625729E006EBCDE at www.airweb.faa.gov because for some reason the usual method got into problem with this address, don't know why)

Quote:

Applicability

(c) This AD applies to the Boeing Model 737-800 series airplanes, certificated in any category, serial numbers 32685, 34277 through 34281 inclusive, 34474, 34475, 34654 through 34656 inclusive, 34690, 34948, 34949, 35091 through 35093 inclusive, 35103, 35134, 35176 through 35183 inclusive, 35330, 35331, 35558, 35559, and 36323 through 36328 inclusive.

Though as a layman I am not sure if that list includes only US registered and or owned aircraft.

[edited because I forgot the initial quote, ehem]

[Edited 2007-05-09 21:12:09]
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EMA747
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 4:29 am

I've found the article. http://www.timesnews.co.ke/06may07/nwsstory/news1.html
Here is the bit about it being a SFP version:

Quote:
In mid July last year, Boeing design enhancements that increased the short-field performance of the Next-Generation 737, including the 737-800, earned certification from the US Federal Aviation Administration following a successful four-month flight-test program. European Aviation Safety Agency certification was expected to follow soon.

Marconi Avionics Group announced then the award of Supplemental Type Certification (STC) by the Federal Aviation Administration (FAA) for full operational use of the HUD 2020 Visual Guidance System (VGS) on Boeing 737-800 aircraft.

These measures included adding the payload capacity, ability to land in short runways and navigate through harsh weather. The plane that went down yesterday had these advancements.

That info is wrong actually because if you look here http://www.planespotters.net/Product.../737-800/index.html?sort=9&start=5
or even type 5Y-KYA into the search page here on a.net is shows it as being a 737-8AL(WL).
Failing doesn’t make you a failure. Giving up and refusing to try again does!
 
OPNLguy
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 4:42 am

Quoting EMA747 (Reply 201):
That info is wrong actually because if you look here http://www.planespotters.net/Product.../737-800/index.html?sort=9&start=5
or even type 5Y-KYA into the search page here on a.net is shows it as being a 737-8AL(WL).

I suspect that the article's author simply found anything/everything about the 737NG family and SFP improvments, but failed to notice the the SFP stuff was an "option". The Boeing press release from July 2006 (announcing the SFP improvements) mentions that GOL and some (10 or so) other airlines had ordered SFP versions, but I didn't see Kenya listed. As the aircraft was delivered after July, and more towards the end of the year, I'm assuming it wasn't a SFP version, and whomever looked up the S/N and cross-checked it with the S/N's in affected AD seems to come to the same conclusion.

I'm hoping AWST will publish some info on the public (read: "free") side of their website. I'd believe any info that they put out over the conventional media.
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
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zeke
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 4:49 am

Quoting Rwessel (Reply 180):
I'd suggest continuing to take the 30s estimate with a large grain of salt.

The 30 seconds comment came from the Kenya Airways chief pilot James Ouma who said Kenyan investigators believe the jet crashed about 30 seconds after takeoff, and was found on its flight path.

A lot of estuary type terrain is on the flight path off runway 12, it has the Wouri river to the north, and the Sanaga to the south.

The normal departure routes can be found on the ASECNA AIS website and the topographic charts for the area can be found on the links below (about 7 mb each)

Douala (7.1 MB)
French Congo(7.4 MB)

Given the flight time and distance from the airport, it is unlikely the aircraft achieved 1000' in altitude.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
jaysit
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 5:03 am

Quoting EMA747 (Reply 196):
Pics from the crash site make it look like there was none/very little fire. I would have thought a plane crashing nose down or nearly nose down into the ground with fuel for a 4+ hour flight would have burst into flames?

Ditto for the ValueJet crash in the Everglades.

And that aircraft's foreward cargo hold was on fire, and it nosedived from a much higher altitude.
Atheism is Myth Understood.
 
JoeCanuck
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 5:05 am

Quoting Pilotaydin (Reply 192):

As far as I can tell, most investigators come to conclusions based on facts and try to avoid coming to conclusions based on suppositions and theories. The purpose of this is so they can maintain an open mind and not prejudice any conclusions with preconceptions.

Instead of wasting resources and time proving, (or disproving), every theory that comes down the pike, (no matter how likely), they start with the facts and work towards a logical conclusion based on them. They don't start with theories and work backwards. If there isn't enough information to support any definitive conclusion, they say that too.

I'll be stunned if you can find any NTSB people guessing about how this tragedy occurred.
What the...?
 
Electech6299
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 6:20 am

Quoting JoeCanuck (Reply 205):
I'll be stunned if you can find any NTSB people guessing about how this tragedy occurred.

I won't, quite the opposite. My job is very similar in nature- conducting controlled experiments and using only hard scientific data to formulate conclusions (or evaluate other evidence-based conclusions). Yet everyone in my profession is always in "technical inquiry" mode, asking questions and trying out theories. It's part of the job, and a beneficial practice because it keeps the mind sharp, inquisitive, and open. The only one who might not partake in these theoretical exchanges is the lead person on a particular project, for two reasons: 1) The project involves work-related stress, and it's not helpful to add to this by talking about your own work. It's better to keep the exchange theoretical, discussing someone else's work. 2) Because that person usually has more hard data and relevant information about the particular study that they have to focus on, so they are not open to entertaining theoretical possibilities that do not match the study conditions.

In the end, it's the study author (in aviation, the lead investigator) who issues the definitive report. That should always be respected, because no one else has the information and technical backing available to that person. However, there is nothing wrong with engaging in scientific debate about a situation, actual or theoretical, and there is nothing wrong with asking questions of the report author. (That's what peer review is for).

So I would bet that there are lots of NTSB investigators out there following the news and entertaining pet theories- just not the ones actually doing the investigation. If you only want to discuss "investigation-worthy evidence", don't waste your time on threads like this one. Sit back and watch for the preliminary and final reports. Happy reading!
Send not to know for whom the bell tolls...it tolls for thee
 
rwessel
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 8:55 am

Quoting Irobertson (Reply 195):
Just something picky, but depending on this whole windshear theory, 250kts is *indicated* speed, am I right? True airspeed could have been a hell of a lot faster, especially if the wind suddenly changed direction...? Or am I talking out of my butt here?

At sea level IAS will be equal to true airspeed, modulo any calibration or system errors. It's at higher altitudes that true airspeed starts to significantly exceed indicated airspeed.

And if the wind suddenly changed from a strong tailwind to a strong headwind (sort of a reverse microburst), both the indicated and true airspeed of the aircraft would suddenly increase, while the ground speed would not change. If the headwind continues, the aircraft will, without any other changes, climb until it slows back to its trimmed airspeed (presumably the same IAS/TAS as before the wind shift), which will reduce the ground speed.

Anyway, a sudden switch from a tailwind to a headwind might cause a pretty good bump, but it's not dangerous as it will temporarily increase the performance of your aircraft (IOW, your aircraft will want to climb some). It's the sudden switch from a headwind to a tailwind that makes microbursts so dangerous.
 
pilotaydin
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 11:47 am

Quoting JoeCanuck (Reply 205):

Even when they have the facts, such as air florida flight 90, they STILL can't put a finger on WHY the pilots did what they did....so there is guess work and assumptions/theories even AFTER all facts are in... palm 90 showed an EPR of 2.2 when they were actually indicating 1.8......that's a fact....but you can't bring out facts about decisions that weren't made, i respect your point and agree with it partially....but then at the same time, you aren't wasting any time, you need something to get your head around while you wait for the facts, there will be no ruling anything out.
The only time there is too much fuel onboard, is when you're on fire!
 
philb
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 4:12 pm

Quoting Rwessel (Reply 207):
Anyway, a sudden switch from a tailwind to a headwind might cause a pretty good bump, but it's not dangerous as it will temporarily increase the performance of your aircraft (IOW, your aircraft will want to climb some). It's the sudden switch from a headwind to a tailwind that makes microbursts so dangerous.

Even more dangerous is vertical windshear which is present in microbursts within their core but is also present in active CBs and can lift a large aircraft at a rate of several thousand feet a minute, well beyond design limits, and then cease leaving the aircraft in an "upset" condition with the crew unable to re-orientate and devoid of any sensible instrument readings.
 
XT6Wagon
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 5:11 pm

Quoting Philb (Reply 209):
Even more dangerous is vertical windshear which is present in microbursts within their core but is also present in active CBs and can lift a large aircraft at a rate of several thousand feet a minute, well beyond design limits, and then cease leaving the aircraft in an "upset" condition with the crew unable to re-orientate and devoid of any sensible instrument readings.

Hmm, updraft causing massive rate of climb for a short time, they or the autothrottle back off the throttle a hell of alot... then bam the other side, down draft, engines at idle or flamed out due to rain and a quick trip into the swamp? Or switch from headwind to tail wind could do it too, I would guess. Certainly not going to have the time to correct ANY mistake if one is made just after takeoff in a heavy storm.
 
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saleya22r
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 5:51 pm

1. How reliable is the METAR at Douala in the first place given that there is no radar service? Are only visual observations used? For example METAR at the time of the accident suggested zero wind. How can this be correct?
2. As far as the jammed spoilers hypothesis is concerned, would the aircraft with spoilers deployed be able to rotate and climb in the first place?One might expect that it had crashed somewhere even nearer the treshold?
 
philb
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 6:02 pm

Quoting Saleya22R (Reply 211):
For example METAR at the time of the accident suggested zero wind. How can this be correct?

Depends on whiere the wind reading was taken and when. An airfield can have different wind speeds and directions over different parts of the field.

Even here in Ireland some of the Atlantic showers can cause very different conditions at one end of the 10,000 foot long 06/24 runway to the other, especially if the general wind direction is southerly. Ideally a runway should have three wind monitors - one each end and one in the middle and, in poor conditions, these should be passed to the crews of arriving and departing aircraft and any significant change should be notified immediately.
 
PYP757
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 11:29 pm

Quoting JoeCanuck (Reply 176):
I find it somewhat ironic that there is often so much criticism on A.net of the media, for incorrect aeronautical information and unsubstantiated reporting and when something like this happens, we all have to present our own unsubstantiated theories until we're all, eventually, proven wrong.

I cannot understand why some people on A.net always object to speculating on the causes of accidents. Nobody forces them to read the threads that appear here. If they want, they can just wait for the final reports, which can take months or years to be published depending on the country where the crash takes place. Personally, I am far too curious to wait that long, and I find a lot of the theories developped here quite plausible and interesting. So thank you everyone for your vey insightful comments.
 
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zeke
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RE: Kenya Airways 737-800 Lost PT. 2

Thu May 10, 2007 11:42 pm

Quoting Saleya22R (Reply 211):
1. How reliable is the METAR at Douala in the first place given that there is no radar service? Are only visual observations used? For example METAR at the time of the accident suggested zero wind. How can this be correct?

A metar is only for Wx a few miles about an airport, the majority of metars do not use any form of radar data to generate the observations.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
Electech6299
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RE: Kenya Airways 737-800 Lost PT. 2

Fri May 11, 2007 12:05 am

Quoting Saleya22R (Reply 211):
As far as the jammed spoilers hypothesis is concerned, would the aircraft with spoilers deployed be able to rotate and climb in the first place?One might expect that it had crashed somewhere even nearer the treshold?

The failure described in the AD (AD 2007-06-51) is for a single actuator to be jammed in the deployed position, causing the single spoiler panel (or set of panels) to remain deployed. This does not affect the other spoilers. The concern is that if a plane did take off with a single set of spoilers deployed, the lift characteristics of that wing will be different and cause the aircraft to roll. IMHO, the drag from a single set of spoilers should not significantly affect the aircraft takeoff performance (but I could be wrong).

For those familiar with the 738, how many spoiler panels/actuators are on each wing?
Send not to know for whom the bell tolls...it tolls for thee
 
David L
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RE: Kenya Airways 737-800 Lost PT. 2

Fri May 11, 2007 12:30 am

Quoting PYP757 (Reply 213):
I cannot understand why some people on A.net always object to speculating on the causes of accidents.

Agreed but I confess I do get a bit irritated when someone becomes fixated on a single cause in spite of a lack of evidence or the presence of more evidence for a different cause.
 
wjcandee
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RE: Kenya Airways 737-800 Lost PT. 2

Fri May 11, 2007 1:22 pm

FWIW, this seems to be the latest, from AP (fair use excerpt): http://www.ctv.ca/servlet/ArticleNew...wreckage_070510/20070510?hub=World

"Investigators were focusing initially on the pilot's decision to take off despite predictions a thunderstorm would last up to an hour more, an official familiar with the inquiry said. The Nairobi-bound Boeing 737-800 nose-dived into a swamp seconds after taking off Saturday from an airport, killing all 114 people on board.


"Why did other planes wait for the storm to pass and not him? That's the question," said the Cameroonian official, who spoke on condition of anonymity because of the sensitivity of the subject.


The pilot waited an hour because of weather, but Douala airport had predicted the storm would last for another hour. The official said the pilot of a Royal Air Maroc jetliner that was next to take off waited another 45 minutes after the Kenya Airways flight left and encountered no turbulence.


According to aviation regulations, cockpit crews are free to take off in bad weather unless the local flight control takes extraordinary measures such as temporarily closing the airport.


The last statement above raises an issue that has been in my head since the accident. A buddy who flies a similar-size jet for a major carrier used to like to talk about how individual airline policies regarding "no fly" conditions can lead to different results and can affect safety at the margins. He describes sitting at a major airport in high wind conditions and watching a 737 from a smaller carrier taxi out to the runway in conditions that meant that his airline's policies precluded his aircraft from taking off. So he was sitting at the gate watching the show. The guy got hit with a massive blast of tailwind just after the mains lifted off, and my buddy says that it was as close as he has ever seen in person a transport-category aircraft come near crashing; the guy almost lost it, and probably did for a brief moment. He presumed that there existed some wet seats in various parts of the plane. Given that it now appears that the gear was cycling and the flaps weren't fully-retracted, a weather scenario as the initiating cause seems likely. And it makes me feel a bit validated for having the attitude as I sit sometimes in Atlanta during thunderstorms with passengers lining up bitching about why we can't get take off, if the pilot doesn't want to go, or his airline's policy won't let him go, I'm happy to wait.
 
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zeke
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RE: Kenya Airways 737-800 Lost PT. 2

Fri May 11, 2007 1:31 pm

Quoting Wjcandee (Reply 217):
The last statement above raises an issue that has been in my head since the accident. A buddy who flies a similar-size jet for a major carrier used to like to talk about how individual airline policies regarding "no fly" conditions can lead to different results and can affect safety at the margins. He describes sitting at a major airport in high wind conditions and watching a 737 from a smaller carrier taxi out to the runway in conditions that meant that his airline's policies precluded his aircraft from taking off.

The metars from 1600 to 0200 that day indicated the highest recorded wind was 5 kt, at the time of the accident nil wind was reported in the metar.

I assume the 738 has all the latest doppler Wx rardar with a predictive wind shear function.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
philb
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RE: Kenya Airways 737-800 Lost PT. 2

Fri May 11, 2007 3:49 pm

Quoting Zeke (Reply 218):
The metars from 1600 to 0200 that day indicated the highest recorded wind was 5 kt, at the time of the accident nil wind was reported in the metar.

I assume the 738 has all the latest doppler Wx rardar with a predictive wind shear function.

As stated before, the METARS only show the wind at the point of measurement. They are a GUIDE which, in normal conditions do a job. See my post #212 and have a read of the document referred to in #144.

As to on board equipment, it is only as good as the notice taken of it and the use to which that information is put. All cars have speedometers but thousands of drivers are caught speeding every day - and I'm not accussing the crew of the aircraft, just pointing out a truism.
 
wjcandee
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RE: Kenya Airways 737-800 Lost PT. 2

Sat May 12, 2007 9:13 am

I hesitated to start a new thread on this, but I commend to you all the following AP article, which is a model of clarity, non-hype and accuracy for the layman reader. It discusses the latest developments in the investigation, and clarifies some of the earlier inaccurate information. (The only mistake I saw was the reference to the model of 737 involved.) I appreciate that it covers the "Who was flying?" topic that readers always seem to want to know, but then correctly makes the point that the captain always has final authority. Etc. An unusually-good article, especially given the fact that there isn't much new information.

http://www.kcbs.com/topic/ap_news.ph.../a/i/Cameroon-CrashProbe_a_i_-----
 
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zeke
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RE: Kenya Airways 737-800 Lost PT. 2

Sat May 12, 2007 9:22 am

Quoting Philb (Reply 219):
See my post #212 and have a read of the document referred to in #144.

The information you posted is very basic, a gust front associated with a thunderstorm would have shown up on a metar over that period of time, I have flown about the tropics for many years, I am well versed with the life cycle of a tropical thunderstorm.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
OPNLguy
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RE: Kenya Airways 737-800 Lost PT. 2

Sat May 12, 2007 10:28 am

Quoting Wjcandee (Reply 220):
I hesitated to start a new thread on this, but I commend to you all the following AP article, which is a model of clarity, non-hype and accuracy for the layman reader.

I concur--a pretty good article. One wishes that more aviation articles could be as such...

Based on what was mentioned in the article, it sounds like another example of PA759, complete with other crews electing to continue waiting, while one didn't.....

Quoting OPNLguy (Reply 160):
In 1982, just before Pan Am 759 went down, one of our crews declined ATC's offer of a departure on runway 10. Our aircraft was pointed east, and the captain, using the aircraft weather radar, simply didn't like what he saw off the end of the runway, and decided to take an additional delay, as did some other aircraft. PA759 apparently thought what they saw was acceptable, and launched, and the rest is history.

Back in 1985 when Delta 191 went down due a microburst at DFW, the fact that it was an L-1011 was in a way a benefit safety-wise, since its DFDR recorded more data parameters compared with other aircraft of the time. Various folks put this data to good use, and TDWR, improved flight simulator programs, and onboard windshear detection equipment were developed or enhanced. It's been reported that the DFDR on this 738 records 1,000 different parameters, and if true, and further, if the Kenya 738 was a repeat of the PA759 microburst encounter, hopefully the new data obtained from the DFDR will make TDWR, sim programming, and onboard windshear setection equipment that much better...
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
wjcandee
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RE: Kenya Airways 737-800 Lost PT. 2

Sat May 12, 2007 11:20 am

Quoting OPNLguy (Reply 222):
Based on what was mentioned in the article, it sounds like another example of PA759, complete with other crews electing to continue waiting, while one didn't.....

I concur. Obviously, it's important for the investigators and, to some extent, the media to shine a light on all possibilities, but the smart money has been on the most obvious cause -- a PA759-type scenario -- for as long as most "experts" in the media have been speculating about wings being ripped off and Airworthiness Directives regarding flaps and mechanical failure, etc. I guess people just don't want to believe that something so catastrophic can be caused by a little less focus on caution and a little more focus on getting there.

I like the often-used Edmund Fuller quotation: "It's appalling to see what trivial things can be among the causes of massive disaster."

Or to quote Jacob van Zanten: ""We gaan."


A decent little synopsis of PA759 can be had at: http://www.pilotfriend.com/disasters/crash/panam759.htm
 
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Buyantukhaa
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RE: Kenya Airways 737-800 Lost PT. 2

Sat May 12, 2007 11:57 am

Quoting Wjcandee (Reply 223):
I like the often-used Edmund Fuller quotation: "It's appalling to see what trivial things can be among the causes of massive disaster."

Or to quote Jacob van Zanten: ""We gaan."

Well said....
I scratch my head, therefore I am.
 
OPNLguy
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RE: Kenya Airways 737-800 Lost PT. 2

Sat May 12, 2007 12:01 pm

Quoting Wjcandee (Reply 223):
A decent little synopsis of PA759 can be had at: http://www.pilotfriend.com/disasters...9.htm

This accident is also one of many covered in Dr. Fujita's "The Microburst" that came out in the mid-1980s. He also did another book soley on the Delta 191 crash. They're both out of print, but if you can find used ones on eBay or elsewhere, they're great reads...
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
Electech6299
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RE: Kenya Airways 737-800 Lost PT. 2

Sat May 12, 2007 12:40 pm

Quoting Wjcandee (Reply 220):
there isn't much new information

I agree, good article, but it clears up quite a bit of the speculation we have been wondering about on this thread.

Quote:
The site is less than 3 miles from Runway 12

That suggests that our other references to 3.2 miles were incorrect.

Quote:
The wreckage indicated the plane flew nose-first into the ground at a nearly 90-degree angle. It was found buried deep in a crater of reddish-brown muck with only tiny bits of the rear fuselage and wings left above ground.

So much for the "controlled ditching" theories. This was a severe stall, at a high enough altitude to permit a steep dive.

Quote:
The location of the wreckage also indicates the pilot was banking sharply to the right. This would have exposed the raised left wing to the gust, investigators said.

That's new- and once again raises the specter of control surface (spoiler?) asymmetry. (I know, extremely unlikely, but still possible) The way I read it, the pilot most likely tried to make a maneuver to steer around a thunderhead early in the climbout and got caught with his wingtip down. I suppose only the CVR data will tell the story, but the DFDR data might lend some insight as well. Was the PF fighting only the weather, or was he fighting his own plane as well?

I suppose from here will also be inquiry into Kenya Airlines training for pilots on interpreting weather radar, and airline policies and culture that guide the pilots' decisions. This pilot was ultimately responsible for his decision to fly, but he did not make it in a vacuum. How well does the Chief Pilot stick up for his pilots when they choose to ground an airplane or delay a flight? How much leverage does the Operations side of the business have to make the pilots regret making safe decisions? Is there a culture of respect for safety, or is there a culture of demand for profit? I know that Kenya Airlines has one of the better reputations in the region, but even at the best airlines there is always room to grow.
Send not to know for whom the bell tolls...it tolls for thee
 
philb
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RE: Kenya Airways 737-800 Lost PT. 2

Sat May 12, 2007 6:40 pm

Quoting Zeke (Reply 221):
The information you posted is very basic, a gust front associated with a thunderstorm would have shown up on a metar over that period of time, I have flown about the tropics for many years, I am well versed with the life cycle of a tropical thunderstorm.

Obvoiusly you are far more experienced than the Australian Govt Dept of Meteorology - or didn't you bother to download and read the PDF? I'm sure they will be delighted to have their work dismissed as "very basic".

Perhaps you might be interested in the situation at New Orleans on July 9 1982 when a Pan American 727 took off, made only 95 feet and crashed 12,000 feet from the start of its take off run.

At taxi clearance, with active storm cells in the area, the wind for Runway 10 was 240 at 2 knots. During taxi it became 040 at 8 knots. Four minutes later, with the 727 in the queue, it was 060 at 15 knots, gusting 25 knots with windshear alert, northeast airfield quadrant 330 degrees 10 knots, northwest quadrant 130 at 3 knots.

A minute later the runway wind was given as 070 degrees 17 knots, peak gust 23 knots, low level windshear alert for all quadrants.

A 767 landing immediately before the 727 lined up reported a 10 knot widshear at 100 feet on finals. The 727 then took off and, at 95 feet, started descending and struck trees 700 metres beyon the end of the runway, then hit and destroyed houses.

Immediately before the 727 took off, a Republic DC9 took off and during the roll met heavy rain and windshear. Its Vr had been calculated as 132 knots, V2 at 140 knots but the captain rotated at 121 knots, the stick shaker briefly vibrated but the aircraft started to climb and, as they passed the end of the runway, the airspeed increased from 132 knots to 160 knots "in an instant".

As the 727 began to roll the rain was falling at 25mm per hour but, at the far end of the runway it was in excess of 50mm per hour..

During the period of the accident, and contrary to the actual readings, the airport's recording anenometer showed an average wind of 16 knots but, two seconds after the 727 struck the trees, the windshear alert equipment showed 080 degrees 15 knots at the centre of the runway and 310 degrees at 6 knots at the end beyond which the 727 crashed.

Meteorological studies since have concluded that the downdraught associated with the microburst that generated the windshear would have been in excess of 600 feet per minute (10 feet per second). Combined with the windshear, this was a fatal combination for an aircraft the size of the 727, using full take off power and with the air conditioning packs off to gain maximum thrust from the outboard engines.

The point of all of this is to highlight the fact that, even in 1982, New Orleans had far better weather detection equipment than Douala now has and yet a jet, operated by a well managed company, flown by a very experienced crew, crashed. Given the similarity in weather, the fact that Douala has poor equipment and that there was similar thunderstorm activity and how close to the airport the aircraft crashed, the effect of thunderstorms on airframes, dismissed by many on this and the previous thread, will not be being taken lightly by the investigation.
 
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zeke
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RE: Kenya Airways 737-800 Lost PT. 2

Sat May 12, 2007 7:06 pm

Quoting Philb (Reply 227):
Obvoiusly you are far more experienced than the Australian Govt Dept of Meteorology - or didn't you bother to download and read the PDF? I'm sure they will be delighted to have their work dismissed as "very basic".

If you learned something from that great, but it is still at a very basic level, all of that is standard ATPL knowledge. The difference naturally as it closer to the equator, tops of thunderstorms can go past 50,000' as thats how high the tropopause is. The life cycle of a thunderstorm has not changed since I used to teach CPL pilots years ago.

Quoting Philb (Reply 227):
At taxi clearance, with active storm cells in the area, the wind for Runway 10 was 240 at 2 knots. During taxi it became 040 at 8 knots. Four minutes later, with the 727 in the queue, it was 060 at 15 knots, gusting 25 knots with windshear alert, northeast airfield quadrant 330 degrees 10 knots, northwest quadrant 130 at 3 knots.

A minute later the runway wind was given as 070 degrees 17 knots, peak gust 23 knots, low level windshear alert for all quadrants.

Thats very nice, but the facts for the airport on the day don't support such a dramatic and colourful story....

FKKD 051600Z 26005KT 9999 SCT016 FEW020CB BKN300 29/25 Q1008 NOSIG
FKKD 051500Z 27004KT 9999 BKN016 FEW020CB BKN120 30/25 Q1008 NOSIG
FKKD 051400Z 26005KT 9999 BKN016 FEW020CB BKN120 31/25 Q1009 NOSIG
FKKD 051300Z 27004KT 9999 BKN016 FEW020CB BKN120 30/25 Q1010 NOSIG
FKKD 051200Z 33005KT 9999 BKN016 FEW020CB BKN120 30/25 Q1011 NOSIG
FKKD 051100Z 34004KT 9999 BKN016 FEW020CB BKN120 29/24 Q1012 NOSIG
FKKD 051000Z 00000KT 9999 BKN016 FEW020CB BKN120 28/24 Q1012 NOSIG
FKKD 050900Z 00000KT 9999 BKN016 FEW020CB BKN120 27/24 Q1012 NOSIG
FKKD 050800Z 00000KT 9999 SCT016 FEW020CB BKN120 26/25 Q1012 RETS NOSIG
FKKD 050700Z 00000KT 9999 TS BKN015 FEW016CB BKN120 25/24 Q1011 NOSIG
FKKD 050600Z 00000KT 9999 TS BKN013 FEW016CB BKN120 24/24 Q1010 NOSIG
FKKD 050500Z 15003KT 9999 TS BKN013 FEW020CB BKN120 24/24 Q1010 NOSIG
FKKD 050400Z 00000KT 9999 TS BKN013 FEW020CB BKN120 24/24 Q1010 NOSIG
FKKD 050300Z 00000KT 9999 TS BKN013 SCT020CB OVC120 24/24 Q1009 NOSIG
FKKD 050200Z 00000KT 9999 TS BKN013 SCT020CB BKN120 24/24 Q1009 NOSIG
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
philb
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RE: Kenya Airways 737-800 Lost PT. 2

Sat May 12, 2007 7:37 pm

Quoting Zeke (Reply 228):
If you learned something from that great, but it is still at a very basic level, all of that is standard ATPL knowledge. The difference naturally as it closer to the equator, tops of thunderstorms can go past 50,000' as thats how high the tropopause is. The life cycle of a thunderstorm has not changed since I used to teach CPL pilots years ago.

I learnt most of the thunderstorm basics in the 1960s and have been following the growth in knowledge ever since. I posted the link to help those on here who, somehow, have the impression that thunderstorms are benign and safe to fly through in modern aircraft. Perhaps they, and you, should read Page 45.

Quoting Zeke (Reply 228):
Thats very nice, but the facts for the airport on the day don't support such a dramatic and colourful story....

It isn't a nice, dramatic and colourful story. It is FACT taken from the official report and commentaries thereto by aviation and meteorological experts.

Quoting Zeke (Reply 228):
FKKD 051600Z 26005KT 9999 SCT016 FEW020CB BKN300 29/25 Q1008 NOSIG
FKKD 051500Z 27004KT 9999 BKN016 FEW020CB BKN120 30/25 Q1008 NOSIG...etc


Exactly, you amplify my point. Those readings are taken from a fixed point and show a slight increase in wind speed and some wide variance in direction over a 6 minute period. A similar read out from the recording equipment at New Orleans for a 15 minute period before and during the take off run of the 727 on July 9 1982 showed a fairly steady average of 16 knots from 070 or 080 degrees but - as was proved - the real picture around the airfield was vastly different and, just beyond the airfield boundary, was beyond survivability for a 727.
 
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zeke
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RE: Kenya Airways 737-800 Lost PT. 2

Sat May 12, 2007 11:15 pm

Quoting Philb (Reply 229):
Exactly, you amplify my point. Those readings are taken from a fixed point and show a slight increase in wind speed and some wide variance in direction over a 6 minute period.

Nope, you cannot seem to be able to read a metar, those reading are over a 10 hour period (1700-0300 local on the 5th), they are not in minutes,

I had a look at page again, could not see anything new, I fly in the tropics all the time, all that stuff is common sense.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
comorin
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RE: Kenya Airways 737-800 Lost PT. 2

Sat May 12, 2007 11:16 pm

Dumb question - much has been made here of modern airliners having weather radar, but how effective is it when sitting on the runway?

Thanks.
 
pilotaydin
Posts: 2100
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RE: Kenya Airways 737-800 Lost PT. 2

Sun May 13, 2007 8:04 am

Quoting Comorin (Reply 231):
Dumb question - much has been made here of modern airliners having weather radar, but how effective is it when sitting on the runway?

it's very very effective actually some of them function once you advance the throttles to mid position, otherwise it would pick up vortexes left and right and constantly scream windshear...
The only time there is too much fuel onboard, is when you're on fire!
 
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HAWK21M
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Joined: Fri Jan 05, 2001 10:05 pm

RE: Kenya Airways 737-800 Lost PT. 2

Sun May 13, 2007 6:00 pm

Quoting Comorin (Reply 231):
Dumb question - much has been made here of modern airliners having weather radar, but how effective is it when sitting on the runway

Quite effective with Tilt.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
philb
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Joined: Mon May 24, 1999 5:53 am

RE: Kenya Airways 737-800 Lost PT. 2

Sun May 13, 2007 6:02 pm

Quoting Zeke (Reply 230):
Nope, you cannot seem to be able to read a metar, those reading are over a 10 hour period (1700-0300 local on the 5th), they are not in minutes,

I had a look at page again, could not see anything new, I fly in the tropics all the time, all that stuff is common sense.

Fair point, misread the times as I had a much shorter time scale in my head as I'd been reading up on the Pan American crash where there is a list of readings in minutes and I was replying in a rush before going out for the day. Even so it doesn't destroy my point about METARS being a reading from a fixed point and giving a general picture which can be vastly different from what is happening in close proximity.

If you fly through the tropics all the time and have an interest in the work done on protecting aircraft from storms your comment:

Quoting Zeke (Reply 228):
Thats very nice, but the facts for the airport on the day don't support such a dramatic and colourful story....

surprises me as it minimises the importance of that accident, its effect on the knowledge base and how it affected and led to changes in the US programme of installation of low level windshear alert equipment and led to specific work on microburst prediction, detection and avoidance.

Of course Douala, 25 years after that accident, has none of that equipment. Once the cause of the accident has been determined the question of why the flight took off (even if the cause was mechanical) needs to be asked, given other flights waited another 45 minutes and more for the weather to abate.
 
srbmod
Topic Author
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Joined: Tue Mar 20, 2001 1:32 pm

RE: Kenya Airways 737-800 Lost PT. 2

Sun May 13, 2007 11:25 pm

With this thread getting well past 200 posts, it's being locked (mainly for the benefit of those following the thread on slower connections) and please continue the discussion in the thread linked below.
Kenya Airways 737-800 Lost PT. 3 (by Srbmod May 13 2007 in Civil Aviation)

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