Boeing 737 - 600/700/800/900. Operations Manual (1997 year) - page 4
Operations Manual Bulletin No. TBC-6, Dated January 29, 1999 (continued)
Administrative Information
Insert this bulletin behind the Operations Manual Bulletin Record page in
Volume 1 of your Operations Manual. Amend the Operations Manual Bulletin
Record to show bulletin TBC-6 “In Effect” (IE).
This condition is temporary until Service Bulletin 737- 27-1215 is installed.
CS3-2712
Page 2 of 2
Sect Name
Section Name
Operations Manual Bulletin
for
The Boeing Company
The Boeing Company
Seattle, Washington 98124-2207
s
Number: TBC-7
Date: January 29, 1999
Document Effectivity: D6-27370-TBC
Subject: Engine Overheat/Fire and APU Fire Detection
Reason: To inform flight crews of a potential malfunction of the engine
overheat/fire and APU fire detection system.
Information in this bulletin is recommended by The Boeing Company, but may not be FAA approved
at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual (AFM),
the AFM shall supersede. The Boeing Company regards the information or procedures described
herein as having a direct or indirect bearing on the safe operation of this model airplane.
THE FOLLOWING PROCEDURE AND/OR INFORMATION IS EFFECTIVE UPON RECEIPT
Background Information
A defect in the manufacturing process of the engine and APU fire detector loops
may allow a slow leak of the internally contained helium gas. This slow leak may
result in an increase in the predetermined temperature limit for a fire or overheat
condition alert.
The wheel well fire detection and wing-body overheat detection systems are not
affected.
Boeing issued an All-Operator telex, same subject, requesting the operators to
inspect their 737-700 series airplanes and spares inventory to identify the fire
detector assemblies and fire detector elements serial numbers. Flight crews flying
airplanes with suspect parts should use the operating instructions contained in this
bulletin until repairs have been completed.
Page 1 of 2
Operations Manual Bulletin No. TBC-7, Dated January 29, 1999 (continued)
Operating Instructions
Engine Overheat
If an engine overheat condition occurs (ENG OVERHEAT light illuminates), it
should be treated as an engine fire and the Engine Fire, Severe Damage or
Separation non-normal procedure should be accomplished.
APU Operation
The APU system does not have overheat detection and the predetermined
temperature limit for a APU fire may have increased. The APU should not be
operated in flight unless an emergency condition requires its use. If the APU is
started in flight, land at the nearest suitable field.
Note: Dispatch configurations requiring the use of the APU during flights are not
authorized i.e. Dispatch with an Engine Driven Generator System inoperative.
Administrative Information
Insert this bulletin behind the Operations Manual Bulletin Record page in
Volume 1 of your Operations Manual. Amend the Operations Manual Bulletin
Record to show bulletin TBC-7 “In Effect” (IE).
This condition is temporary until the system is modified. The All-Operator telex
provides instructions on how to receive replacement parts.
CS3-2702
Page 2 of 2
Sect Name
Section Name
Operations Manual Bulletin
for
The Boeing Company
The Boeing Company
Seattle, Washington 98124-2207
s
Number: TBC-8R1
Date: December 17, 1999
Document Effectivity: D6-27370-TBC
Subject: UNCOMMANDED ENGINE ACCELERATION DUE TO AN
ENGINE FUEL CONTROL FAULT
Reason: This is a reissue of TBC-8, dated January 29, 1999, which informed
flight crews of a CFM 56-7 engine anomaly. The purpose of this reissue
is to provide Service Bulletin information.
Information in this bulletin is recommended by The Boeing Company, but may not be FAA approved
at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual (AFM),
the AFM shall supersede. The Boeing Company regards the information or procedures described
herein as having a direct or indirect bearing on the safe operation of this model airplane.
THE FOLLOWING PROCEDURE AND/OR INFORMATION IS EFFECTIVE UPON RECEIPT
Background Information
There have been five (5) cases of uncommanded fuel flow accelerations on
CFM56-7 engines. These are the result of an engine fuel control anomaly that can
lead to excessive fuel flow, causing uncommanded thrust increase, engine RPM
and/or EGT limit exceedances, or engine surge.
The first three (3) events occurred at near idle engine power during approach. For
two (2) of the three (3) events, flight crew action was necessary to shutdown the
effected engine.
Two (2) subsequent events of uncommanded fuel flow accelerations occurred on
an airplane which had EEC Software version 7BI installed. These events occurred
on the ground, one while parking at the gate and one while taxiing. It should be
noted this software was designed to minimize but not eliminate repeat occurrences
of uncommanded fuel flow acceleration.
Page 1 of 4
Operations Manual Bulletin No. TBC-8R1, Dated December 17, 1999 (continued)
Alert Service Bulletin CFM56-7B S/B
73-A026, dated January
20,
1999,
introduced EEC software version 7.B.J which provided a significant improvement
in the Fault Accommodation Logic. There have been no additional uncommanded
engine acceleration events since the release of software version 7.B.J. This Alert
Service Bulletin and this Operations Manual Bulletin apply to airplanes with
manufacturer’s line numbers 1 through 193. Line number 194 and on received the
software fix during production.
In addition, a review of the current
737 non-normal procedures has been
conducted and the results include a new procedure for an engine limit, surge, stall
condition. This change aligns the 737 non-normal procedure with other Boeing
models’ non-normal procedure. This new procedure was incorporated in Rev. 2,
dated July 31, 1998, of the TBC Operations Manual.
Operating Instructions
If one or more of the following occurs, perform the Engine Limit/Surge/Stall
procedure:
•engine RPM or EGT indications are abnormal, approaching or exceeding limits
•no response to thrust lever movement
•abnormal engine noises.
Note: Flight crews should remain vigilant for uncommanded engine acceleration
during all phases of flight.
Administrative Information
This bulletin replaces bulletin TBC-8, dated January 29, 1999. Discard bulletin
TBC-8. Revise the Bulletin Record page to show TBC-8 as “Cancelled” (CANC).
Insert this bulletin behind the Operations Manual Bulletin Record page in
Volume 1 of your Operations Manual. Revise the Bulletin Record page to show
bulletin TBC-8R1 “In Effect” (IE).
This bulletin will be cancelled after Boeing is notified that all affected airplanes
in your fleet have been modified by Alert Service Bulletin CFM56-7BS/B 73-
A026. If you do not plan to modify all your airplanes and would like to have the
contents of this bulletin incorporated in your Operations Manual, please advise
Boeing accordingly.
Page 2 of 4
Operations Manual Bulletin No. TBC-8R1, Dated December 17, 1999 (continued)
Please send all correspondence regarding Operations Manual Bulletin Status to
one of the following addresses:
Mailing Address Manager, Flight Technical Publications
737 Model
Boeing Commercial Airplane Group
P.O. Box 3707 MS 20-89
Seattle, WA 98124-2207
USA
Fax:
(206) 662-7812
Telex:
329430 Station 627
SITA:
SEABO7X Station 627
CS3-2723
Page 3 of 4
Operations Manual Bulletin No. TBC-8R1, Dated December 17, 1999 (continued)
Intentionally
Blank
Page 4 of 4
Sect Name
Section Name
Operations Manual Bulletin
for
The Boeing Company
The Boeing Company
Seattle, Washington 98124-2207
s
Number: TBC-9
Date: January 29, 1999
Document Effectivity: D6-27370-TBC
Subject: APU DC FUEL PUMP OPERATIONAL ANOMALY
Reason: To inform flight crews of an APU DC fuel pump operational anomaly.
Information in this bulletin is recommended by The Boeing Company, but may not be FAA approved
at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual (AFM),
the AFM shall supersede. The Boeing Company regards the information or procedures described
herein as having a direct or indirect bearing on the safe operation of this model airplane.
THE FOLLOWING PROCEDURE AND/OR INFORMATION IS EFFECTIVE UPON RECEIPT
Background Information
The APU DC Fuel Pump is intended to provide pressurized fuel to the APU when
no AC fuel pump is operating.
Flight testing has revealed that the APU DC fuel pump will not operate
automatically when the APU fuel control senses a low fuel pressure condition,
unless the center tank fuel pump switches are in the ON position. This condition
is caused by the routing of the low fuel pressure signal through the center tank
pump switches. When these switches are in the OFF position, the low pressure
signal is interrupted.
Operating Instructions
With the center tank fuel pump switches in the OFF position, the APU DC fuel
pump does not function as described in the Operations Manual and should be
treated as inoperative.
Note: With no AC power available and the DC fuel pump inoperative, APU starts
are not recommended above 25,000 feet.
Operations Manual Information
The Non-Normal Procedure page for Loss of Both Engine Driven Generators has
been revised to include the above Note.
Page 1 of 2
Operations Manual Bulletin No. TBC-9, Dated January 29, 1999 (continued)
Administrative Information
Insert this bulletin behind the Operations Manual Bulletin Record page in
Volume 1 of your Operations Manual. Amend the Operations Manual Bulletin
Record to show bulletin TBC-9 “Incorporated” (INC).
This condition is temporary until the system is modified. This bulletin will be
revised to include Service Bulletin information when available.
CS3-2728
Page 2 of 2
Sect Name
TBC-10R1Section Name
Operations Manual Bulletin
for
The Boeing Company
The Boeing Company
Seattle, Washington 98124-2207
s
Number: TBC-10R1
Date: September 10, 1999
Document Effectivity: D6-27370-TBC
Subject: LANDING ALTITUDE DISPLAY ANOMALY
Reason: This is a reissue of TBC-10, dated January 29, 1999, which informed
flight crews of a landing altitude display anomaly. The purpose of this
reissue is to provide additional information regarding the anomaly as
well as information regarding the FMC software upgrade to correct the
anomaly.
Information in this bulletin is recommended by The Boeing Company, but may not be FAA approved
at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual (AFM),
the AFM shall supersede. The Boeing Company regards the information or procedures described
herein as having a direct or indirect bearing on the safe operation of this model airplane.
THE FOLLOWING PROCEDURE AND/OR INFORMATION IS EFFECTIVE UPON RECEIPT
Background Information
On the PFD altitude indication, landing altitude is displayed as an amber
crosshatched area indicating:
• the FMC landing altitude for the destination runway or airport, or
• the landing altitude for departure runway or airport until 400 NM from
departure or one-half the distance to destination, whichever occurs first.
Flight testing has revealed that an incorrect landing altitude indication may appear
after flight plan entry. This anomaly will in turn result in an incorrect transition
altitude indication. FMC Update U10.3, due early first quarter 2000, will correct
both anomalies.
Operating Instructions
Re-enter the flight plan route and verify correct landing altitude is displayed.
Page 1 of 2
Operations Manual Bulletin No. TBC-10R1, Dated September 10, 1999 (continued)
Administrative Information
This bulletin replaces bulletin TBC-10, dated January 29, 1999. Discard bulletin
TBC-10. Revise the Bulletin Record page to show TBC-10 as “Cancelled”
(CANC).
Insert this bulletin behind the Operations Manual Bulletin Record page in
Volume 1 of your Operations Manual. Amend the Operations Manual Bulletin
Record to show bulletin TBC-10R1 “In Effect” (IE).
This condition is temporary until the system is modified. This bulletin will be
revised to include Service Bulletin information when available.
CS3-2736
Page 2 of 2
Sect Name
Section Name
Operations Manual Bulletin
for
The Boeing Company
The Boeing Company
Seattle, Washington 98124-2207
s
Number: TBC-11R1
Date: March 26, 1999
Document Effectivity: D6-27370-TBC
Subject: COLLINS ILS/GPS MULTI-MODE RECEIVER (MMR) FAILURE
Reason: This is a reissue of TBC-11, dated January 29, 1999, which informed
flight crews of the lack of failure indications associated with certain
internal Multi-Mode Receiver (MMR) failures. The purpose of this
reissue is to add Service Bulletin information.
Information in this bulletin is recommended by The Boeing Company, but may not be FAA approved
at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual (AFM),
the AFM shall supersede. The Boeing Company regards the information or procedures described
herein as having a direct or indirect bearing on the safe operation of this model airplane.
THE FOLLOWING PROCEDURE AND/OR INFORMATION IS EFFECTIVE UPON RECEIPT
Background Information
Flight testing has shown that certain internal MMR failures can occur which do
not display fault indications or failure flags. In this event, the associated ILS and
GPS will not function. ILS frequency, localizer deviation and glideslope deviation
indicators will not be displayed. Normal GPS functions and updates will not be
available and the altitude range arc will move erratically if displayed.
Collins GLU-920 Service Bulletins (8 and 10 through 15) provide information on
the upgrade that fixes the anomaly.
Operating Instructions
If course and glideslope deviation indicators are not displayed, consider the event
as an ILS receiver failure. Dual channel approach and autoland will not be
available. Consider the effect on approach minimums and select an appropriate
course of action. When flight conditions permit, view FMC Position Page 2 and
determine if a GPS position is missing. If so, consider the associated GPS receiver
as failed.
Page 1 of 2
Operations Manual Bulletin No. TBC-11R1, Dated March 26, 1999 (continued)
Administrative Information
This bulletin replaces bulletin TBC-11, dated January 29, 1999. Discard bulletin
TBC-11. Revise the Bulletin Record page to show TBC-11 as “Cancelled”
(CANC).
Insert this bulletin behind the Operations Manual Bulletin Record page in
Volume 1 of your Operations Manual. Amend the Operations Manual Bulletin
Record to show bulletin TBC-11R1 “In Effect” (IE).
This bulletin will be cancelled after Boeing is notified that all affected airplanes
in your fleet have been modified by Collins GLU-920 Service Bulletins (8 and 10
through 15). If you do not plan to modify all your airplanes and would like to have
the contents of this bulletin incorporated in your Operations Manual, please advise
Boeing accordingly.
Please send all correspondence regarding Operations Manual Bulletin Status to
one of the following addresses:
Mailing Address Manager, Flight Technical Publications
737 Model
Boeing Commercial Airplane Group
P.O. Box 3707 MS 20-89
Seattle, WA 98124-2207
USA
Fax:
(206) 662-7812
Telex:
329430 Station 627
SITA:
SEABO7X Station 627
CS3-2737
Page 2 of 2
Sect Name
Section Name
Operations Manual Bulletin
for
The Boeing Company
The Boeing Company
Seattle, Washington 98124-2207
s
Number: TBC-12R1
Date: September 6, 1999
Document Effectivity: D6-27370-TBC
Subject: INADVERTANT RTO AUTOBRAKING DURING LANDING
Reason: This is a reissue of TBC-12, dated January 29, 1999, which informed
flight crews of the potential risk of RTO braking during landing on 737-
600/700/800 airplanes. The purpose of this reissue is to provide Service
Letter information.
Information in this bulletin is recommended by The Boeing Company, but may not be FAA approved
at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual (AFM),
the AFM shall supersede. The Boeing Company regards the information or procedures described
herein as having a direct or indirect bearing on the safe operation of this model airplane.
THE FOLLOWING PROCEDURE AND/OR INFORMATION IS EFFECTIVE UPON RECEIPT
Background Information
A 737-800 operator has reported three incidents of inadvertent selection of RTO
braking during landing roll. In each case, flight crews were attempting to disarm
the autobrakes by placing the Auto Brake Select Switch to the "OFF" position.
The RTO events were caused by over-rotating the switch past the "OFF" position
to the "RTO" position. Boeing Flight Test and Boeing Engineering have
confirmed that RTO arming and application logic in the autobrake system may
allow RTO braking to engage if the switch is placed in the "RTO" position at any
speed after landing autobraking has initiated.
Boeing Service Letter
737-SL-32-078 provides information concerning an
autobrake software modification to re-verify the arming conditions when RTO is
selected during landing roll. This modification will prevent RTO braking even if
the switch is inadvertently placed in the "RTO" position during landing.
Page 1 of 2
Operations Manual Bulletin No. TBC-12R1, Dated September 6, 1999 (continued)
Operating Instructions
Although the autobrake system can be disarmed by placing the Auto Brake Select
Switch in the "OFF" position, Boeing recommends the use of manual braking to
disarm the autobrake system. Flight crews may also disarm the autobrakes by
moving the SPEED BRAKE lever to the down detent if speed brakes are not
further required to assist stopping.
Administrative Information
This bulletin replaces bulletin TBC-12, dated January 29, 1999. Discard bulletin
TBC-12. Revise the Bulletin Record page to show TBC-12 as “Cancelled”
(CANC).
Insert this bulletin behind the Operations Manual Bulletin Record page in
Volume 1 of your Operations Manual. Amend the Operations Manual Bulletin
Record to show bulletin TBC-12R1 “In Effect” (IE).
This bulletin will be cancelled after Boeing is notified that all affected airplanes
in your fleet have been modified by Service Letter 737-SL-32-078. If you do not
plan to modify all your airplanes and would like to have the contents of this
bulletin incorporated in your Operations Manual, please advise Boeing
accordingly.
Please send all correspondence regarding Operations Manual Bulletin Status to
one of the following addresses:
Mailing Address Manager, Flight Technical Publications
737 Model
Boeing Commercial Airplane Group
P.O. Box 3707 MS 20-89
Seattle, WA 98124-2207
USA
Fax:
(206) 662-7812
Telex:
329430 Station 627
SITA:
SEABO7X Station 627
CS3-2752
Page 2 of 2
Sect Name
Section Name
Operations Manual Bulletin
for
The Boeing Company
The Boeing Company
Seattle, Washington 98124-2207
s
Number: TBC-13R1
Date: April 23, 1999
Document Effectivity: D6-27370-TBC
Subject: NUISANCE PWS FAIL ANNUNCIATION
Reason: This is a reissue of TBC-13, dated January 29, 1999, which informed
flight crews of predictive windshear system operational conditions that
can cause the subject annunciation to be displayed. The purpose of this
reissue is to provide Service Bulletin information.
Information in this bulletin is recommended by The Boeing Company, but may not be FAA approved
at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual (AFM),
the AFM shall supersede. The Boeing Company regards the information or procedures described
herein as having a direct or indirect bearing on the safe operation of this model airplane.
THE FOLLOWING PROCEDURE AND/OR INFORMATION IS EFFECTIVE UPON RECEIPT
Background Information
Flight testing and customer reports have confirmed that a nuisance PWS FAIL
annunciation will occur for approximately
30 seconds under the following
conditions:
• WXR has not been selected on at any time since electrical power up, and
• one or both engines are advanced for takeoff and the indicated airspeed is
increasing.
This applies to the Allied Signal weather radar system with the Predictive
Windshear function activated.
(Allied Signal/Bendix weather radar system
receiver-transmitter part number 066-50008-0405). The message will extinguish
approximately 30 seconds after appearing.
Allied Signal/Bendix Service Bulletin RTA-4B-34-97
(M4508) corrects the
anomaly. This service bulletin converts the weather radar RT unit part number
from 066-50008-0405 to 066-50008-0406.
All airplanes prior to Line Number 347 are affected. Follow-on airplanes will have
the -0406 receiver-transmitters installed prior to delivery.
Page 1 of 2
Operations Manual Bulletin No. TBC-13R1, Dated April 23, 1999 (continued)
Operating Instructions
To prevent the annunciation from occurring, select the weather radar system on
prior to takeoff. The weather radar may then remain on or be turned off as desired
for the remainder of the flight. Consider any subsequent PWS FAIL annunciation
or WINDSHEAR alert as valid.
Administrative Information
This bulletin replaces bulletin TBC-13, dated January 29, 1999. Discard bulletin
TBC-13. Revise the Bulletin Record page to show TBC-13 as “Cancelled”
(CANC).
Insert this bulletin behind the Operations Manual Bulletin Record page in
Volume 1 of your Operations Manual. Amend the Operations Manual Bulletin
Record to show bulletin TBC-13R1 “In Effect” (IE).
This bulletin will be cancelled after Boeing is notified that all affected airplanes
in your fleet have been modified by Allied Signal/Bendix Service Bulletin RTA-
4B-34-97 (M4508).
If you do not plan to modify all your airplanes and would like to have the contents
of this operations manual bulletin incorporated in your Operations Manual, please
advise Boeing accordingly.
Please send all correspondence regarding Operations Manual Bulletin Status to
one of the following addresses:
Mailing Address Manager, Flight Technical Publications
737 Model
Boeing Commercial Airplane Group
P.O. Box 3707 MS 20-89
Seattle, WA 98124-2207
USA
Fax:
(206) 662-7812
Telex:
329430 Station 627
SITA:
SEABO7X Station 627
CS3-2765
Page 2 of 2
Sect Name
Section Name
Operations Manual Bulletin
for
The Boeing Company
The Boeing Company
Seattle, Washington 98124-2207
s
Number: TBC-14
Date: January 29, 1999
Document Effectivity: D6-27370-TBC
Subject: AFDS PERFORMANCE DEGRADATION WITH RADIO
ALTIMETER FAILURE
Reason: To inform flight crews of potential AFDS performance degradation
associated with certain Radio Altimeter failure modes.
Information in this bulletin is recommended by The Boeing Company, but may not be FAA approved
at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual (AFM),
the AFM shall supersede. The Boeing Company regards the information or procedures described
herein as having a direct or indirect bearing on the safe operation of this model airplane.
THE FOLLOWING PROCEDURE AND/OR INFORMATION IS EFFECTIVE UPON RECEIPT
Background Information
The LNAV function of the flight management computer (FMC) is limited to a
bank angle limit of 30 degrees by the flight control computers (FCC) when the
radio altitude is 400 feet or greater. Below 200 feet, LNAV is limited to 8 degrees
of bank angle. Between 200 and 400 feet bank angle is limited to 15 degrees. The
actual bank angle commanded by the FMC will be within these bounds.
Flight testing has confirmed that certain radio altimeter failure modes can cause
degraded autopilot flight director system (AFDS) performance. These failure
modes may not cause an amber RA failure flag to be displayed.
If a radio altimeter fails while transmitting a valid altitude of less than 200 feet or
if the radio altimeter output never becomes valid after power up on the ground, the
associated FCC, which uses that radio altimeter as its primary source of data, will
use the last valid altitude received or use zero feet if no valid altitude is received
after power-up. This will result in the LNAV command on that side always being
limited to 8 degrees of bank angle, during either autopilot or flight director
Page 1 of 2
Operations Manual Bulletin No. TBC-14, Dated January 29, 1999 (continued)
operation. Depending on the aggressiveness of the programmed turns of the active
LNAV path, this failure could result in the airplane departing the LNAV path if the
FMC desired commands exceed the AFDS bank limits. This failure will be
indicated by the airplane symbol not following the defined (magenta) path as
shown on the Navigation Display.
Operating Instructions
Boeing procedures emphasize the need for pilot monitoring of automated systems
to ensure acceptable performance in flight. In this case, vigilant flight path
monitoring will reveal the radio altimeter failure as a deviation from the FMC
computed path when using LNAV guidance. This failure will also cause a flight
director disagreement in LNAV mode. The flight director associated with the
failed radio altimeter will be limited to 8 degrees of bank. The flight director
associated with the operating radio altimeter will not be bank angle limited unless
the airplane is below 400 feet AGL. If these effects occur, the flight crew must
utilize other appropriate methods of flight path control at their disposal. These
methods include but are not limited to: use of manual flight modes to keep the
airplane on the FMC path or use of VOR guidance to track appropriate radials if
the LNAV track overlays VOR airway structure. Additionally, the autopilot and
flight director LNAV steering commands will be normal from the FCC associated
with a functioning radio altimeter.
Administrative Information
Insert this bulletin behind the Operations Manual Bulletin Record page in
Volume 1 of your Operations Manual. Amend the Operations Manual Bulletin
Record to show bulletin TBC-14 “In Effect” (IE).
This condition is temporary until the system is modified. This bulletin will be
revised to include Service Bulletin information when available.
CS3-2776
Page 2 of 2
Sect Name
Section Name
Operations Manual Bulletin
for
The Boeing Company
The Boeing Company
Seattle, Washington 98124-2207
s
Number: TBC-15
Date: January 29, 1999
Document Effectivity: D6-27370-TBC
Subject: FMC Software Restart Anomaly
Reason: To inform flight crews of potential FMC software restarts caused by
certain CDU inputs during flight.
Information in this bulletin is recommended by The Boeing Company, but may not be FAA approved
at the time of writing. In the event of conflict with the FAA approved Airplane Flight Manual (AFM),
the AFM shall supersede. The Boeing Company regards the information or procedures described
herein as having a direct or indirect bearing on the safe operation of this model airplane.
THE FOLLOWING PROCEDURE AND/OR INFORMATION IS EFFECTIVE UPON RECEIPT
Background Information
Boeing has confirmed an airline report of FMC anomalies which can cause
software restarts during flight. When in the descent phase of flight, if the flight
crew EXECutes a change to the flight plan on the ACT RTE LEGS or ACT RTE
page and then presses the DES key to display the DES page before predictions
have completed processing, an FMC internal program fault will occur causing an
FMC “software restart.” The FMC navigation function does not correctly recover
from the program fault causing a variety of misleading cockpit displays and lateral
guidance anomalies until the correction is complete. In airplanes with dual FMCs,
the restart can occur in one or both FMCs. In airplanes with a single FMC, the
correction of the program fault may take up to 8 minutes.
Laboratory testing has verified that these anomalies are limited to FMCs loaded
with software version U10.2. These anomalies can cause a significant increase in
pilot workload and have the potential to degrade the flight crew's situational
awareness. LNAV guidance can be unreliable, the MAP display can be oriented
along an erroneous track and a large erroneous wind can be displayed on the MAP
and CDU. The software will be revised as soon as possible. The following specific
flight deck effects are indications of a software restart:
Page 1 of 4