Subject: Boeing 737 AD/B737/198
(Amdt 1) Center Tank Fuel Pumps 8/2005 TX
Applicability: All Model 737-600, -700, -700C, -800 and
-900 series airplanes. Requirement: 1. Model
737-600, -700, -700C, -800 and -900 series airplanes with a line
number 1234 and below:
a. If not previously accomplished in accordance with the original
issue of this Directive - Remove the Aircraft Flight Manual (AFM)
revision required by AD/B737/190 Amdt 1.
b. If not previously accomplished in accordance with the original
issue of this Directive - Revise the Limitations Section of the
Aircraft Flight Manual (AFM) by incorporating the procedures
included at Annex A to this Amendment (this may be accomplished by
inserting a copy of Annex A into the AFM).
The limitations contained in this Amendment supersede any
conflicting
basic AFM limitations.
c. If not previously accomplished in accordance with the original
issue of this Directive - Install a placard adjacent to each
pilot's primary flight display (PFD) that reads as follows:
"AD/B737/198 fuel usage restrictions required"
2. For all Model 737-600, -700, -700C, -800 and -900 series
airplanes:
a. Fuel pumps with the following part numbers may not be installed
on any airplane as a replacement part, unless the pump has been
inspected to ensure that the wire bundle is properly routed in the
pump since the most recent assembly of the end cap and
motor-impeller housing (whether during manufacture, after
maintenance or inspection, or after overhaul) in accordance with
Boeing Alert Service Bulletin (ASB) 737-28A1197 dated 23 September
2002 or Crane Hydro-Aire Service Bulletin (SB) Crane Hydro-Aire
Motor-Impeller-28-01, including Appendix A, dated 17 September
2002:
PART 39 - 105 Hydro-Aire Part Number 60-989100-4, 60-755100-4
Boeing Part Number 60B89004-14, 60B92404-8
b. Fuel pump motor-impeller assembly
having any part number may not be installed on any airplanes in any
pump position as a replacement part, unless the assembly has been
inspected since the most recent assembly of the end cap
motor-impeller housing (whether during manufacture, after
maintenance or inspection, or after overhaul) using X-ray methods
to ensure that the wire bundle is properly routed in the pump in
accordance with Boeing ASB 737-28A1197 or Crane Hydro-Aire SB Crane
Hydro-Aire Motor-Impeller-28-01, including Appendix A.
3. Remove the Requirement 1.b. AFM revision and the Requirement
1.c. placard.
Note 1: Requirement 3 is optional terminating actions for the fuel
usage restrictions
at Requirements 1.b and c.
Note 2: FAA AD 2002-19-52 Amdt 39-12900 refers.
Compliance: For Requirement 1 - Within 14 days
after the effective date of this Amendment.
For Requirement 2 -- As of the effective date of this
Amendment.
For Requirement 3 -- When all fuel pumps for the center wing tank,
horizontal stabilizer tank, center auxiliary tanks, together with
auxiliary fuel tanks 1 and 4 on an airplanes have been inspected
using X-ray methods in accordance with Boeing ASB 737-28A1197 or
Crane Hydro-Aire SB Crane Hydro-Aire Motor-Impeller-28-01,
including Appendix A.
Inspection of a pump by Crane Hydro-Aire before the effective date
of the original issue of this Directive is considered equivalent to
an inspection performed in accordance with Crane Hydro-Aire SB
Crane Hydro-Aire Motor-Impeller-28-01, including Appendix A.
Inspection of a pump in accordance with Boeing ASB 737-28A1197 or
Crane Hydro-Aire SB Crane Hydro-Aire Motor-Impeller-28-01,
including Appendix A, before the effective date of the original
issue of this Directive is acceptable for removal of the AFM
revision and placard. Effective Date: This Amendment becomes
effective on 23 June 2005.
Background: The United States Federal Aviation
Administration (FAA) has received reports indicating that fuel
pumps on Boeing Model 737, 747 and 757 series airplanes have failed
as a result of chafing of the stator lead wire bundle. This
occurred when the stationary wire bundle came into contact with the
rotor in the pump motor. The pumps failed when the pump power was
short-circuited to the rotor and the circuit protection device
tripped. Examination of failed pumps showed that arcing had
occurred in the pump bearings both inside and outside of the
explosion-proof cavity of the pump. Such arcing could result in an
ignition source in the fuel tank. The fuel pump failures have been
attributed to the manufacturing assembly process during which the
stator lead wire bundle was improperly installed and positioned in
the end cap. The original issue of this Directive superseded
AD/B737/190 Amdt 1, which was cancelled. The Directive required an
amendment to the AFM which is intended to ensure that the center
tank pump inlets are covered with fuel during pump operation,
preventing fuel vapors from coming into contact with any ignition
source resulting from a fuel pump failure and installation of a
placard adjacent to both PFDs advising that fuel usage restrictions
apply. The Directive also provided optional terminating action for
Requirements 1.b. and c. This Amendment limits the applicability of
the fuel usage restrictions to airplanes before line number 1234,
whilst at the same time retaining the requirement to ensure that
fuel pumps that have not been inspected are not installed on
airplanes as replacement spares. The original issue of this
Airworthiness Directive became effective on 3 October 2002.
Annex A
Aircraft Flight Manual Revision
Certificate Limitations
The center tank fuel pumps must be OFF for takeoff if center tank
fuel is less than 5,000 pounds (2,300 kilograms) with the airplane
readied for initial taxi. Both center tank fuel pump switches must
be selected OFF when center tank fuel quantity reaches
approximately 1,000 pounds (500 kilograms) during climb and cruise
or 3,000 pounds (1,400 kilograms) during descent and landing. The
fuel pumps must be positioned OFF at the first indication of fuel
pump low pressure. The CWT fuel quantity indication system must be
operative to dispatch with CWT mission fuel.
Note: The CONFIG indicator will annunciate when
center tank fuel exceeds 1,600 pounds (800 kilograms) and the
center tank fuel pump switches are OFF. Do not accomplish the
CONFIG non-normal procedure prior to or during takeoff with less
than 5,000 pounds (2,300 kilograms) of center tank fuel or during
descent and landing with less than 3,000 pounds (1,400 kilograms)
of center tank fuel. Note: In a low fuel situation, both center
tank pumps may be selected ON and all center tank fuel may be
used.
If the main tanks are not full, the zero fuel gross weight of the
airplane plus the weight of center tank fuel may exceed the maximum
zero fuel gross weight by up to 5,000 pounds (2,300 kilograms) for
takeoff, climb and cruise and up to 3,000 pounds (1,400 kilograms)
for descent and landing, provided that the effects of balance (CG)
have been considered. If a center tank fuel pump fails with fuel in
the center tank, accomplish the FUEL PUMP LOW PRESSURE non-normal
procedure. When defuelling center or main wing tanks, the Fuel Pump
Low Pressure indication lights must be monitored and the fuel pumps
positioned to OFF at the first indication of fuel pump low
pressure. Defueling with passengers on board is prohibited.