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B737NG FAA Mandate  
User currently offlineCdfmxtech From United States of America, joined Jul 2000, 1338 posts, RR: 27
Posted (11 years 7 months 6 days 10 hours ago) and read 2090 times:

The rest of the article is below, but I will highlight one statement that doesn't make much sense to me.

Failure of one flight control system can be overcome by using the backup. But failure of both systems can lead to a crash.

The B737 was designed with manual reversion as a backup for a loss of hydraulics. That statement seems like they are saying since for instance that if Aileron PCU "A" which is pwoered by "A" hydraulics loses power - then "B" can compensate. But if u lose "A" & "B", this can lead to a crash.

I know the aircraft is a bit difficult to handle without hydraulics, but it can't be as bad as a B757 using only the RAT. (I've heard this from pilots)

***************************************

US issues emergency order on newer Boeing 737s
Saturday September 14, 2:26 pm ET


WASHINGTON, Sept 13 (Reuters) - U.S. regulators ordered airlines on Saturday to see if their newer Boeing (NYSE:BA - News) 737 aircraft are equipped with a potentially defective part that could make the plane hard to control if it failed.
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Boeing did not install any of the flight control modules in question on planes that it delivered before May 21. But the Federal Aviation Administration said in its emergency order that airlines could be storing a limited number of modules from a suspect batch for use as spare parts on older planes.

The FAA required immediate inspections of the newer models -- 737-600, -700, -700C, -800, and -900 aircraft -- before they be allowed to fly again. The inspections of newer aircraft cover about 100 planes and airlines must also check their inventories of parts.

The 737 series is the world's most widely used commercial jetliner with 2,000 registered to U.S. airlines and another 4,500 operated by foreign-owned carriers.

Each plane is equipped with a primary and a backup flight control system that each have a module to regulate the flow of hydraulic fluid to the rudder, ailerons and elevators.

Ailerons are hinged flaps located near the end of each wing that control aircraft roll during a turn. A plane's rudder helps control the side-to-side swing of the nose, and the elevator panels on the tail's horizontal stabilizer are used during climbs and descents.

Boeing has identified 15 instances in which the module failed to properly regulate hydraulic fluid. Four occurred during flight, but did not result in any accidents. The other 11 failures were found during ground tests.

The cause of the problem has not been determined but could stem from a manufacturing defect, the FAA said. The module is located in the plane's wheel wells.

An interruption in the flow of hydraulic fluid can make the plane sluggish or otherwise hard to control. "It places a significant additional workload on the flight crew," FAA spokesman Les Dorr said.

Failure of one flight control system can be overcome by using the backup. But failure of both systems can lead to a crash.

The FAA has alerted foreign civil aviation authorities so they can take action on their own.


7 replies: All unread, jump to last
 
User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 1, posted (11 years 7 months 5 days 18 hours ago) and read 2039 times:

Ah, the media....

I learned long ago that they do not report the "news."

They report their "opinions" on the news, which are filtered (or limited, take your pick) by their lack of detailed knowledge in specific fields. Air crashes, industrial accidents, politics, you name it.

One of my all-time favorite media gaffes was after our Air Florida 737 crashed at DCA back in 1982. We all know what happened, but one of the stations there reported (with great certainty) that the reason the aircraft crashed was that there had been so much snow and ice on the runway that they couldn't get enough traction.... (As if studded 737 snow tires or chains would have helped!)


User currently offlineAAR90 From United States of America, joined Jan 2000, 3451 posts, RR: 47
Reply 2, posted (11 years 7 months 5 days 16 hours ago) and read 2017 times:

Classic news media..... don't know anything about which they're "reporting."

My understanding is that if a potentially faulty component failed, the aircraft would lose one of the two hydraulic systems (not flight control systems). The 737NG will fly "ok" with only one hydraulic system (just a little sluggish) but will have difficulty with no hydraulic systems (IMHO, slightly better than 757/767 on RAT, but only slightly).




*NO CARRIER* -- A Naval Aviator's worst nightmare!
User currently offlineLMP737 From , joined Dec 1969, posts, RR:
Reply 3, posted (11 years 7 months 5 days 8 hours ago) and read 1977 times:

Cdfmxtech:

Is it the aileron PCU's that they are talking about? I'm on my days off so I don't know what's going on at work (maybe that's a good thing). Anyway all I heard in the press was power control module. The question is, what are they referring to?


User currently offlineCdfmxtech From United States of America, joined Jul 2000, 1338 posts, RR: 27
Reply 4, posted (11 years 7 months 5 days 8 hours ago) and read 1987 times:

They weren't specific.
The only thing off the had that I know controls the flow of hydraulics to all flight controls is the flight controls module (one for each "A" & "B"). The module with the flt controls shutoff valve, spoiler s/o valve and low pressure switches.


User currently offlineRmm From Australia, joined Feb 2001, 521 posts, RR: 1
Reply 5, posted (11 years 7 months 5 days 3 hours ago) and read 1968 times:

I think this is the latest,

http://www1.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/WebNewEmergencyAD/FCDC67F3E74BE8F586256C34001AD395?OpenDocument

Rmm


User currently offlineSinlock From United States of America, joined Dec 2000, 1593 posts, RR: 2
Reply 6, posted (11 years 7 months 4 days 21 hours ago) and read 1939 times:

Here is a copy of the AD. I'll break it down for you later.

Airworthiness Directives

Header Information
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
Docket No. 2002-NM-241-AD; AD 2002-19-51

Regulatory Information

2002-19-51 BOEING: Docket No. 2002-NM-241-AD.

Applicability: All Model 737-100, -200, -200C, -300, -400, -500, -600, -700, -700C, -800, and -900 series airplanes; certificated in any category.

Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (l) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent operation with one failed flight control module (FCM), which could result in reduced controllability of the airplane, or with two failed FCMs, which could result in loss of control of the airplane, accomplish the following:

Inspection

(a) For Model 737-600, -700, -700C, -800, and -900 series airplanes, having line numbers 1136 through 1230 inclusive: Before further flight after receipt of this AD, do an inspection to determine the serial number (S/N) of both flight control modules (FCM), having part number (P/N) 65-44891-7.

Neither FCM with S/N 8726 or Greater Installed

(b) If neither FCM has S/N 8726 or greater, no further action is required by this AD, except for the requirements specified in paragraphs (j) and (k) of this AD.

FCM(s) with S/N 8726 or Greater Installed

(c) If one FCM has S/N 8726 or greater, the airplane may continue to be operated, but within 24 hours after accomplishing the inspection required by paragraph (a) of this AD, do the actions specified in paragraphs (e) through (g) of this AD.

(d) If both FCMs have S/N 8726 or greater, do the actions specified in either paragraph (d)(1) or (d)(2) of this AD.

(1) Before further flight, replace one of the FCMs with a serviceable FCM, having P/N 65-44891-7 with a S/N less than 8726. Thereafter, the airplane may continue to be operated, but within 24 hours after accomplishing the inspection required by paragraph (a) of this AD, do the action specified in paragraphs (e) through (g) of this AD.

(2) Before further flight, replace both FCMs with serviceable FCMs having P/N 65-44891-7 with a S/N less than 8726. Thereafter, no further action is required by this AD, except for the requirements specified in paragraphs (j) and (k) of this AD.

(e) If required by paragraph (c), (d)(1), or (m) of this AD: Revise the Normal Procedures Section of the FAA-approved Airplane Flight Manual (AFM) to include the following (this may be accomplished by inserting this AD into the AFM):


"Pre-Flight Flight Control Module (FCM) Checks:

These checks can be performed any time after the Electric Hydraulic Pump A and B Switches are positioned ON and prior to Engine Start. Ensure ground personnel are clear of all control surfaces. If Minimum Equipment List (MEL) dispatch with one or both autopilot channels inoperative is planned, it is acceptable not to perform the check on the inoperative channel(s).

Flight Control Switch Check

1. Ensure FLT CONTROL A & B switches are ON

2. FLT CONTROL A Switch . . . . OFF
- Verify Flight Controls LOW PRESSURE Light illuminates within 2 seconds.

3. FLT CONTROL A Switch . . . . .ON
- Verify Flight Control LOW PRESSURE Light extinguishes.

4. FLT CONTROL B Switch . . . . OFF
- Verify Flight Controls LOW PRESSURE Light illuminates within 2 seconds.

5.FLT CONTROL B Switch . . . . .ON
- Verify Flight Controls LOW PRESSURE Light extinguishes.

NOTE: Failure of the Flight Control LOW PRESSURE Light to illuminate within 2 seconds may indicate a failure of the related flight control module.

Autopilot Check
1. Ensure IRUs are in the NAV mode

2. A/P ENGAGE Switch . . . . . CMD A
- Wait 10 seconds, and verify light remains ON

3. Disengage A autopilot

4. A/P ENGAGE Switch . . . . . CMD B
- Wait 10 seconds, and verify light remains ON

5. Disengage B autopilot

6. To fail this test, one autopilot will fail to engage and the other will fail to stay engaged.

NOTE: Failure of the autopilots to engage as described in Step 6. may indicate a failure of a flight control module.

WARNING: If either Pre-Flight FCM Checks fails, do not takeoff until the failed module has been replaced."

(f) If required by paragraph (c), (d)(1), or (m) of this AD: Revise the Limitations Section of the FAA-approved AFM to include the following statement (this may be accomplished by inserting this AD into the AFM):

"If a flight control module (FCM), having P/N 65-44891-7 with S/N 8726 or greater is installed, the "Pre-Flight Flight Control Module (FCM) Checks" specified in the Normal Procedures of this AFM must be accomplished before each flight. If either Pre-Flight FCM Checks fails, do not takeoff until the failed module has been replaced. "

(g) If required by paragraph (c), (d)(1), or (m) of this AD: Revise the Non-Normal Procedures Section of the FAA-approved AFM to include the following (this may be accomplished by inserting this AD into the AFM):


"Flight Control Module (FCM) Failure:

Note: If the module fails in flight, neither A nor B autopilot will engage. Other indications include possible increased in flight control forces (similar to manual reversion) and possible yaw damper disengagement.

Failure of a second module in flight could result in serious degradation of airplane controllability, including high control forces.

If a failure is suspected in flight:

Plan to land at the nearest suitable airport
- Crosswind capability may be reduced

Do not turn off any flight control switches

Plan a flaps 15 landing

Use VREF 15 + 5 or VREF ICE + 5"

Note 2: The Limitations, Non-Normal Procedures, and Normal Procedures specified by paragraphs (e) through (g) of this AD are required to be implemented only for airplanes on which suspect FCMs have been installed. However, individual pilots may operate other airplanes on which those suspect FCMs have not been installed, and that are not subject to those limitations and procedures. Therefore, to avoid any confusion or misunderstanding, it is important that airlines have communication mechanisms in place to ensure that pilots are aware, for each flight, whether the Limitations, Non-Normal Procedures, and Normal Procedures apply.

Failures Detected During "Flight Control Check"

(h) If any failure is detected during any "Pre-Flight Flight Control Module (FCM) Checks" specified in paragraph (e) of this AD, before further flight, replace the affected FCM with a serviceable FCM, having P/N 65-44891-7 with a S/N less than 8726.

Reporting Requirement

(i) Submit a report of inspection findings to the Boeing Renton Airline Support Manager, Craig Blankenstein, 2925 South 112th Street, Seattle, Washington 98168; fax (206) 544-9698; at the applicable time specified in paragraph (i)(1) or (i)(2) of this AD. (The report must include the airplane line number and FCM P/N and S/N.) Information collection requirements contained in this AD have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.

(1) For airplanes on which the inspection required by paragraph (a) of this AD is accomplished after receipt of this AD: Submit the report within 10 days after performing the inspection required by paragraph (a) of this AD.

(2) For airplanes on which the inspection required by paragraph (a) of this AD has been accomplished before receipt of this AD: Submit the report within 10 days after receipt of this AD.

Part Installation

(j) For all airplanes: After receipt of this AD, no person shall install an FCM having P/N 65- 44891-7 with a S/N 8726 or greater, on any airplane.

(k) After receipt of this AD, no person shall install a compensator, P/N 10-605603-3, on any FCM having P/N 65-44891-7.

Alternative Methods of Compliance

(l) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

Special Flight Permits

(m) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished, provided that the airplane is operated per the requirements of paragraphs (e) through (g) of this AD, and that there are no known FCM failures upon dispatch.

Effective Date

(n) AD 2002-19-51, issued on September 13, 2002, becomes effective upon receipt.










My Country can beat up your Country....
User currently offlineCdfmxtech From United States of America, joined Jul 2000, 1338 posts, RR: 27
Reply 7, posted (11 years 7 months 4 days 13 hours ago) and read 1902 times:

I do not need it broken down, I just wanted to confirm which component that they were talking it about. I was right, it is the Flight Controls Modules. However, the way th media presented things have me shaking my head.

Each plane is equipped with a primary and a backup flight control system that each have a module to regulate the flow of hydraulic fluid to the rudder, ailerons and elevators.

The "A" and "B" systems aren't considered primary and backup flght control system.


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