ALERT SERVICE BULLETIN 412-20-183

20 November 2020
Revision A, 17 December 2020
Revision B, 22 January 2021

MODEL AFFECTED: 412/412EP

SUBJECT: FUEL CHECK VALVE P/N 209-062-607-001,

INSPECTION AND REPLACEMENT OF.

HELICOPTERS AFFECTED: Serial numbers 33108 through 33213, 34001

through 34036, 36001 through 36648, 36650
through 36657, 36660 through 36672, 36674
through 36680, 36685, 36687, 36689, 36691, 36693,
36695 and 36696, 36700 and 36701 having a Circor
Aerospace (Circle Seal) fuel check valve not
marked “TQL”.

[Serial number 36649, 36658, 36659, 36673, 36681,

36682, 36683, 36684, 36686, 36688, 36690, 36692,
36694, 36697, 36698, 36699, 36702 through 36999,
37002 through 37999, 38001 through 38999 and
39101 through 39999 will have the intent of this
bulletin accomplished prior to delivery.]

COMPLIANCE: Part I: Within the next 25 flight hours or 30 days,

whichever comes first after the release date of the
revision A of this bulletin.

Part II: Within the next 25 flight hours or 30 days,

whichever comes first after accomplishment of Part I
and every 25 flight hours or 30 days thereafter until
Part III is accomplished.

Part III: No later than 600 flight hours or 12 months,

whichever comes first after accomplishment of Part I.

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DESCRIPTION:

Bell recently received a report of a cracked check valve manufactured by Circor

Aerospace (Circle Seal). This check valve was manufactured in 2009 which is outside
of the manufacturing date range (October 2011 – March 2015) addressed by the ASB
412-15-168 Rev A. Corrective actions implemented in 2015 by Circor Aerospace to
prevent cracking of the check valve housings are indicated by the “TQL” marking.

This recent check valve cracking report indicates that additional fuel check valves P/N
209-062-607-001 manufactured by Circor Aerospace (Circle Seal) not having the “TQL”
marking may be susceptible to cracking with time in service.

This Alert Service Bulletin mandates a one-time inspection of the suspected fuel check
valves for housing dimension measurement. Fuel check valves that do not meet the
inspection requirements outlined in the Part I of the Accomplishment Instructions of this
bulletin will require replacement. Valves that are found serviceable after
accomplishment of Part I of this bulletin will not require further inspection or
replacement.

The original release of this bulletin mandated a one-time inspection of fuel check valves
manufactured between 1995 and March 2015 without the “TQL” marking. Following the
original release of this bulletin, Bell received reports from operators indicating that some
fuel check valves did not have a manufacturing date stamped on the housing. Based
on additional information provided by Circor Aerospace, revision A of this bulletin
mandates the inspection of all fuel check valves manufactured by Circor Aerospace at
the Corona facility in California, not having the “TQL” marking. Fuel check valves
manufactured at the Corona facility have the “CORONA CA” marking. Regardless of
the manufacturing date, fuel check valves with the “TQL” marking are not affected by
this bulletin.

The revision A of this bulletin also corrects the Helicopters Affected effectivity.
Helicopters serial numbers 33001 through 33107 do not have the subject check valves
installed, therefore those helicopters have been removed from the Helicopters Affected
section of this bulletin. In addition to minor editorial changes, this revision A corrects the
metric dimension provided in Part I for the fuel check valve outside diameter
measurement.

Revision B of this bulletin corrects an error in the non-affected helicopter serial numbers
block. Revision B does not change the compliance of this bulletin.

Applicability of this bulletin to any spare part shall be determined prior to its installation
on an affected helicopter.

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APPROVAL:

The engineering design aspects of this bulletin are FAA approved for FAA certified
helicopters as listed in the applicable Type Certificate Data Sheet. For non FAA certified
helicopters, the engineering design aspects of this bulletin are Bell Engineering
approved.

CONTACT INFO:

For any questions regarding this bulletin, please contact:

Bell Product Support Engineering

Tel: 1-450-437-2862 / 1-800-363-8023 / productsupport@bellflight.com

MANPOWER:

Approximately 1 man-hour is required to accomplish Part I of this bulletin and 0.5 man-
hour to accomplish Part II. Approximately 1 man-hour per check valve is required to
accomplish Part III of this bulletin. This estimate is based on hands-on time and may
vary with personnel and facilities available.

WARRANTY:

There is no warranty credit applicable for parts or labor associated with this bulletin.

MATERIAL:

Required Material:

The following material is required for the accomplishment of this bulletin and may be
obtained through your Bell Supply Center.

Part Number Nomenclature Qty (Note)

209-062-607-001 Fuel check valve A/R (1)

NOTE 1: Two fuel check valves are installed per helicopter. Replacement will be
required only if the valve does not meet the inspection requirements.

Consumable Material:

None required.

SPECIAL TOOLS:

None required.

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WEIGHT AND BALANCE:

Not affected.

ELECTRICAL LOAD DATA:

Not affected.
REFERENCES:

BHT-412-MM Maintenance Manual, Chapter 28

Alert Service Bulletin 412-15-168 RA

PUBLICATIONS AFFECTED:

None affected.

ACCOMPLISHMENT INSTRUCTIONS:

Part I. Fuel check valve inspection.

1. Prepare the helicopter for maintenance and gain access to the fuel check valves.
The check valves are located in the aft pylon area (Figure 1).

-NOTE-

It is not necessary to remove the fuel check valve for

inspection. Regardless of manufacturing date, any fuel check
valves with the “TQL” marking are not affected by this bulletin.
Fuel check valves manufactured by other suppliers are also
not affected by this bulletin. Fuel check valves with the
“CORONA CA” marking and without the “TQL” marking are
affected by this bulletin. (Figure 2, Details A and B).

2. Verify if the check valves installed are affected by this bulletin.

3. If the check valves are not affected, make an entry in the helicopter logbook and
historical service records indicating the findings and compliance with this Alert
Service Bulletin.

4. If one or both check valves are affected, proceed as follows:

a. Using a caliper or equivalent, measure the check valve housing at the center and
record dimension (Figure 3).

b. Measure the housing at the inlet end where the threaded fitting is installed and
record dimension.

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 c. f the dimension measured at the inlet end is no more than 0.003 inch (0.0762
mm) greater than the measurement at the center, the valve is serviceable and
does not require further inspection or replacement. Make an entry in the
helicopter logbook and historical service records indicating the findings and
compliance with this Alert Service Bulletin.

-NOTE-

Due to possible delay in getting replacement check valves,

Bell recommends that operators place their order as soon as
Part I is accomplished if one or two check valves are found
defective.

d. If the dimension measured at the inlet end is greater than 0.003 inch (0.0762 mm)
when compared to the measurement at the center, the valve will require
replacement. Part III can be accomplished immediately, or Part II can be
accomplished until the defective valve can be replaced in accordance with Part
III.

e. If the defective check valve is not replaced immediately, make an entry in the
helicopter logbook and historical service records indicating the findings and that
Part II must be accomplished every 25 flight hours or 30 days whichever comes
first until Part III is accomplished.

Part II. Recurring 25 flight hour or 30-day inspection.

5. Prepare the helicopter for maintenance and gain access to the fuel check valves
(Figure 1).

6. Using a strong light source, visually inspect the fuel check valves for general
condition and fuel leaks. Inspect for cracks at the inlet end where the threaded fitting
is installed (Figure 3).

7. If a crack is found, replace the check valve prior to next flight. Figure 4 shows an
example of a cracked check valve.

8. If no cracks or any other defects that would cause the valve to be unserviceable are
found, make an entry in the helicopter logbook and historical service records
indicating the findings and that Part II will require accomplishment until Part III is
accomplished.

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Part III. Fuel check valve replacement.

-NOTE-

The accomplishment of Part III constitutes the terminating

action of this ASB.

1. Prepare the helicopter for maintenance and gain access to the fuel check valves
(Figure 1, Details A and B).

2. Refer to the applicable Maintenance Manual and replace defective fuel check
valve(s) (BHT-412-MM, Chapter 28).

3. Make an entry in the helicopter logbook and historical service records indicating
compliance with this Alert Service Bulletin.

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Figure 1. Fuel Check Valves Location

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 Detail A. Circor Aerospace Fuel Check Valve Marked “TQL”

Detail B. Fuel Check Valves not Manufactured by Circor Aerospace

Figure 2. Fuel Check Valves not Affected

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Figure 3. Fuel Check Valve Outside Diameter Measurement

Figure 4. Cracked Fuel Check Valve

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