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New Problem For All 737 Rudders?  
User currently offlineArniePie From Belgium, joined Aug 2005, 1265 posts, RR: 1
Posted (7 years 4 months 3 weeks 4 days ago) and read 8011 times:

http://www.airweb.faa.gov/Regulatory...7400086257275005A3828?OpenDocument

Is this the same as the old issue with the classic and 200 series or something different.

Also am I correct in understanding that it has to be solved pretty quickly?


[edit post]
25 replies: All unread, showing first 25:
 
User currently offlineEI321 From Iraq, joined Jul 2009, 0 posts, RR: 0
Reply 1, posted (7 years 4 months 3 weeks 4 days ago) and read 8001 times:

Wasnt there something about this in flight international last week?

User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 2, posted (7 years 4 months 3 weeks 4 days ago) and read 7989 times:

Quoting ArniePie (Thread starter):
Is this the same as the old issue with the classic and 200 series or something different.

I think the word "superseding" would indicate that the new AD replaces the old AD (for the original rudder issue) and mandates some new items.

SUMMARY: The FAA is superseding an existing airworthiness directive (AD) that applies to all Boeing Model 737 airplanes. The existing AD currently requires installation of a new rudder control system and changes to the adjacent systems to accommodate that new rudder control system. For certain airplanes, this new AD adds, among other actions, repetitive tests of the force fight monitor of the main rudder power control unit (PCU), repetitive tests of the standby hydraulic actuation system, and corrective action; as applicable. For those airplanes, this new AD also adds, among other actions, replacement of both input control rods of the main rudder PCU and the input control rod of the standby rudder PCU with new input control rods, as applicable, which ends the repetitive tests. For certain other airplanes, this new AD adds installation of an enhanced rudder control system in accordance with new service information. This AD results from a report of a fractured rod end of an input control rod of the main rudder PCU and a subsequent report of a fractured rod end of the input control rod of the standby rudder PCU. We are issuing this AD to prevent failure of one of the two input control rods of the main rudder PCU, which, under certain conditions, could result in reduced controllability of the airplane; and to prevent failure of any combination of two input control rods of the main rudder PCU and/or standby rudder PCU, which could cause an uncommanded rudder hardover event and result in loss of control of the airplane.


User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Reply 3, posted (7 years 4 months 3 weeks 3 days 22 hours ago) and read 7737 times:

What's interesting to note about this is that it also applies to the 737NGs, not just (primarily) the 73S/733 as before.

See also:
http://www.airliners.net/discussions/tech_ops/read.main/182492/


User currently offlineDAYflyer From United States of America, joined Sep 2004, 3807 posts, RR: 3
Reply 4, posted (7 years 4 months 3 weeks 3 days 4 hours ago) and read 7020 times:

Quoting ConcordeBoy (Reply 3):
What's interesting to note about this is that it also applies to the 737NGs, not just (primarily) the 73S/733 as before.

Why is that? As I understand it, the 737NGs have an all new rudder system.



One Nation Under God
User currently offlineJetfuel From Australia, joined Jan 2005, 2195 posts, RR: 0
Reply 5, posted (7 years 4 months 3 weeks 3 days 2 hours ago) and read 5568 times:

They have 30 days to do all this work

This AD applies to all Boeing Model 737-100, -200, -200C, - 300, -400, -500, -600, -700, -700C, -800 and -900 series airplanes, certificated in any category

I can forsee some major schedule issues here for many airlines



Where's the passion gone out of the airline industry? The smell of jetfuel and the romance of taking a flight....
User currently offlineExpress1 From , joined Dec 1969, posts, RR:
Reply 6, posted (7 years 4 months 3 weeks 3 days 1 hour ago) and read 5047 times:

that is worrying to know,considering we are catching a Ryanair B738 flight out of LUTON to ROME in the morning!!!!

 eek 

dave


User currently offlineGlideslope From United States of America, joined May 2004, 1601 posts, RR: 0
Reply 7, posted (7 years 4 months 3 weeks 3 days ago) and read 4276 times:

Looks like a bad batch of control rods discoverd during testing. I's not every 737. Only the ones with the "defective Control Rods" were installed in. Seems to me they have an good idea where they went.

It's a supplier Q&C issue. Not a design issue. The failure was discovered in a Boeing mandated test. What lead to that test is not in the article.



To know your Enemy, you must become your Enemy.” Sun Tzu
User currently offlineMagyar From Hungary, joined Feb 2000, 599 posts, RR: 0
Reply 8, posted (7 years 4 months 3 weeks 2 days 22 hours ago) and read 3932 times:

Quoting Jetfuel (Reply 5):
This AD applies to all Boeing Model 737-100, -200, -200C, - 300, -400, -500, -600, -700, -700C, -800 and -900 series airplanes, certificated in any category



Quoting Glideslope (Reply 7):
Looks like a bad batch of control rods discoverd during testing. I's not every 737. Only the ones with the "defective Control Rods" were installed in. Seems to me they have an good idea where they went.

It's a supplier Q&C issue. Not a design issue. The failure was discovered in a Boeing mandated test. What lead to that test is not in the article.

When did the last 737 classic roll out? They have this "defective rod" issue for some time.


User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Reply 9, posted (7 years 4 months 3 weeks 2 days 21 hours ago) and read 3849 times:

Quoting DAYflyer (Reply 4):
Why is that? As I understand it, the 737NGs have an all new rudder system.

it's right there in the directive... 681 of them were delivered with "fractures in the rods have been caused by a quality control issue that resulted in the units becoming 'over-baked and brittle'".


User currently offlineWingnut767 From , joined Dec 1969, posts, RR:
Reply 10, posted (7 years 4 months 3 weeks 2 days 18 hours ago) and read 3642 times:

For certain airplanes, that NPRM proposed to add, among other actions, repetitive tests of the force fight monitor of the main rudder power control unit (PCU), repetitive tests of the standby hydraulic actuation system, and corrective action; as applicable. For those airplanes, that NPRM also proposed to add, among other actions, replacement of both input control rods of the main rudder PCU and the input control rod of the standby rudder PCU with new input control rods, as applicable, which would end the repetitive tests.

We partially agree. We agree with Southwest Airlines that no further work is required by paragraph (g) for airplanes on which the input control rods have been replaced in accordance with paragraph (g)(4) of this AD. We also find that no further work is required by paragraph (h) for airplanes on which the input control rods have been installed in accordance with paragraph (h) of this AD.

Quoting DAYflyer (Reply 4):
Quoting ConcordeBoy (Reply 3):
What's interesting to note about this is that it also applies to the 737NGs, not just (primarily) the 73S/733 as before.

Why is that? As I understand it, the 737NGs have an all new rudder system.

The modified rudder packages are still going into the 737NG. They have not all been done. This is an addition to the AD already being done. Also the standby rudder and control rod are not being modified at this time. This seems to change that with the recurring inspections and tests.

Quoting Jetfuel (Reply 5):
They have 30 days to do all this work

This AD applies to all Boeing Model 737-100, -200, -200C, - 300, -400, -500, -600, -700, -700C, -800 and -900 series airplanes, certificated in any category

For the replacement of the input control rod of the standby rudder PCU: This AD specifies a compliance time of within 90 days after the effective date of this AD whereas Boeing Alert Service Bulletin 737-27A1279 specifies a compliance time of 24 months.

Regarding the reduced compliance times described previously, an unsafe condition exists that requires the immediate adoption of this AD; therefore, providing notice and opportunity for public comment before the AD is issued is impracticable, and good cause exists to make this AD effective in less than 30 days.

30 days to take effect and then 90 days to comply.




[


User currently offlineIkramerica From United States of America, joined May 2005, 21456 posts, RR: 60
Reply 11, posted (7 years 4 months 3 weeks 2 days 17 hours ago) and read 3500 times:

Quoting Jetfuel (Reply 5):
I can forsee some major schedule issues here for many airlines

If you read closely, i don't believe this is true. The AD covers a subset of planes, and we really don't know which they are, how many, and whether some of these jets have already had this done as a precaution.



Of all the things to worry about... the Wookie has no pants.
User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Reply 12, posted (7 years 4 months 3 weeks 2 days 15 hours ago) and read 3350 times:

Quoting Ikramerica (Reply 11):
how many,

...actually, that one it does specify.


User currently offlineADiZzy From United States of America, joined Jan 2007, 171 posts, RR: 0
Reply 13, posted (7 years 4 months 3 weeks 2 days 15 hours ago) and read 3339 times:

Sounds like Southwest is going to have alot of work to do over the next week. To bad they dont have a second type of craft in their fleet!

User currently offlineAsstChiefMark From , joined Dec 1969, posts, RR:
Reply 14, posted (7 years 4 months 3 weeks 2 days 15 hours ago) and read 3332 times:

Oh dear God! What's Northwest gonna do?

Mark  Silly


User currently offlineDfwRevolution From United States of America, joined Jan 2010, 957 posts, RR: 51
Reply 15, posted (7 years 4 months 3 weeks 2 days 15 hours ago) and read 3308 times:

Quoting ADiZzy (Reply 13):
Sounds like Southwest is going to have alot of work to do over the next week. To bad they dont have a second type of craft in their fleet!

I don't think they have any regrets...  Yeah sure


User currently offlineSonic67 From United States of America, joined Jan 2005, 292 posts, RR: 0
Reply 16, posted (7 years 4 months 3 weeks 2 days 15 hours ago) and read 3281 times:

Quoting EI321 (Reply 1):
Wasnt there something about this in flight international last week?

http://www.flightglobal.com/articles...es-resurface-despite-redesign.html

The article states the Boeing delivered 880 of which 681 were discovered to have been delivered with "suspect rods".


User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 17, posted (7 years 4 months 3 weeks 2 days 15 hours ago) and read 3277 times:

Quoting ADiZzy (Reply 13):
Sounds like Southwest is going to have alot of work to do over the next week. To bad they dont have a second type of craft in their fleet!

SWA has 266 -700s in the fleet out of a total of 485 aircraft. *IF* all 266 were being grounded by the AD, I'd say you might possibly have a point. Since they're not, I'd say you don't...  Wink

Quoting DfwRevolution (Reply 15):
I don't think they have any regrets...

Roger that...  Wink


User currently offlineIkramerica From United States of America, joined May 2005, 21456 posts, RR: 60
Reply 18, posted (7 years 4 months 3 weeks 2 days 15 hours ago) and read 3246 times:

Quoting ConcordeBoy (Reply 12):
...actually, that one it does specify.

What I meant was we know how many were shipped that way, but we don't know how many have already been repaired per the AD. I highly doubt an airline like WN, for example, wasn't warned of the preliminary change in advance...



Of all the things to worry about... the Wookie has no pants.
User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Reply 19, posted (7 years 4 months 3 weeks 2 days 13 hours ago) and read 3151 times:

Quoting OPNLguy (Reply 17):
SWA has 266 -700s in the fleet

...though this doesn't only apply to the -700 (not saying you're suggesting that either).


User currently offlineAdria From , joined Dec 1969, posts, RR:
Reply 20, posted (7 years 4 months 3 weeks 2 days 9 hours ago) and read 3011 times:

After 3 crashes they still didn't manage to fix the problem?

User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Reply 21, posted (7 years 4 months 3 weeks 2 days 1 hour ago) and read 2767 times:

Quoting Adria (Reply 20):
After 3 crashes they still didn't manage to fix the problem?

...more than three; and despite patch after patch, the root problem still (and apparently, will always until the 737 is replaced by another model) remain(s).


User currently offlineSonic67 From United States of America, joined Jan 2005, 292 posts, RR: 0
Reply 22, posted (7 years 4 months 3 weeks 2 days ago) and read 2687 times:

Quoting ConcordeBoy (Reply 21):
...more than three; and despite patch after patch, the root problem still (and apparently, will always until the 737 is replaced by another model) remain(s).

This is a separate issue regarding possible cracked rods but some of the parts where part of the rudder control replacement.


The new rudder control system that includes new components such as an aft torque tube, hydraulic actuators, and associated control rods, and additional wiring throughout the airplane to support failure annunciation of the rudder control system in the flight deck. The system also incorporate two separate inputs, each with an override mechanism, to two separate servo valves on the main rudder power control unit (PCU); and an input to the standby PCU that also include an override mechanism.

IMG of new rudder control.
http://www.airliners.net/uf/view.fil...7524&filename=1171911422cfHvk2.jpg


User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Reply 23, posted (7 years 4 months 3 weeks 1 day 21 hours ago) and read 2585 times:

Quoting Sonic67 (Reply 22):
The new rudder control system that includes new components such as an aft torque tube, hydraulic actuators, and associated control rods, and additional wiring throughout the airplane to support failure annunciation of the rudder control system in the flight deck. The system also incorporate two separate inputs, each with an override mechanism, to two separate servo valves on the main rudder power control unit (PCU); and an input to the standby PCU that also include an override mechanism.

Good stuff, but two questions immediately spring:
1) how many currently have this?
2) when will all be required to have this in service?


User currently offlineAdria From , joined Dec 1969, posts, RR:
Reply 24, posted (7 years 4 months 2 weeks 5 days 23 hours ago) and read 2396 times:

So is the 737NG still safe to fly within those 30 days?

User currently offlineFlashmeister From United States of America, joined Apr 2000, 2900 posts, RR: 6
Reply 25, posted (7 years 4 months 2 weeks 5 days 19 hours ago) and read 2293 times:
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Quoting Adria (Reply 24):
So is the 737NG still safe to fly within those 30 days?

Yes, unless you work for a news outlet or are an associate of Scary Mary Schiavo.  Smile

I mean, seriously... thousands and thousands of these things flying around (plenty, by the way, with the old rudder design too) and yet they manage not to fall out of the sky at the drop of a hat. You're in far greater danger driving a brand new car off the lot than you are taking a hop on a 20-year-old 737... despite what NBC News might say.


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