28-40 Fuel Flow Check
1. Open mast fairing per § 53-22. Remove engine cowling per § 53-21.
2. Refer to Figure 28-1. Attach a temporary hose to one of the vent weldment openings.
With the fuel cap installed, blow into the hose (do not use compressed air) and verify
air blows out the other vent opening. If air does not blow out the other vent, remove
obstruction(s) in vent line(s) or in fuel bladder and repeat check.
3. Defuel helicopter per § 12-42, then service helicopter with 19.4 gallons of fuel per §
12-41.
4. Weigh a suitable, empty container having a volume of at least one gallon. Record
weight of empty container in table below.
5. Pull fuel valve into off position and disconnect B283-12 hose assembly from the engine
fuel inlet fitting.
6. Using a second, suitable container, push fuel valve into on position and drain fuel into
second container for a few seconds to purge system of air. Then fill the weighed
container for 60 seconds. Weigh and record weight of empty container & 60 seconds
of fuel flow in table below.
7. Perform the following calculation:
Combined weight of empty container & 60 seconds fuel flow:
lb
Subtract Weight of empty container:
—
lb
Equals Weight of 60 seconds fuel:
=
lb
8. Minimum fuel flow (at 19.4 gallons of fuel) is 4.75 lb/min (60 seconds). If fuel flow
is less than 4.75 lb/min, remove obstruction(s) in vent line(s), fuel bladder, fuel hoses,
fuel valve, or fuel strainer (inside bladder at outlet), and repeat check until fuel flow is
satisfactory.
9. Close mast fairing per § 53-22. Install engine cowling per § 53-21.
Page 28.14 Chapter 28 Fuel System APR 2017
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