IGV SYSTEM BINDS WHEN IGV ACTUATOR LEVER IS MOVED BY HAND

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3-2. TROUBLESHOOTING - CONTINUED

g.INLET GUIDE VANE (IGV)

( 2 ) E S - 2 6 . IGV SYSTEM BINDS WHEN IGV

- CONTINUED

ACTUATOR LEVER IS MOVED BY HAND.

This section contains troubleshooting to determine why binding is felt

when the IGV actuator lever is moved by hand. V a r i a b l e i n l e t g u i d e v a n e s

(IGVs) are located in the inlet housing behind the inlet support struts.

The individual vanes are coupled together and controlled by a unison

ring which is connected to a bellcrank outside the engine through an

inlet guide control. The bellcrank is attached to a connecting link

which attaches to the IGV actuator lever. The IGV actuator lever is

coupled to the IGV actuating cylinder piston through a connecting link.

The air bleed butterfly valve control rod is also coupled to the IGV

actuator lever. Movement of the IGV actuating cylinder causes the IGV

actuator lever to move and turn the bellcrank to reposition the IGVS and

also move the rod to reset the butterfly valve. The cylinder piston is

controlled by fuel flow from the electro-mechanical fuel system (EMFS)

which is regulated by the electronic control unit (ECU) .A feedback

control (cable) is connected, by quick-release pins, between the EMFS

and the IGV actuator lever. This reflects the actual setting of the IGVs

back to the EMFS and ECU for reference. A faulty air bleed valve, IGV

a c t u a t i n g c y l i n d e r , IGV feedback control, or EMFS could cause binding.

C l o g g e d f u e l l i n e s a t t h e a c t u a t i n g c y l i n d e r , damage or wear on the IGV

actuator lever and bushing, bellcrank, inlet guide control, connecting

links and connecting hardware could also cause binding. The art on this

page provides an overview of the IGV system. Refer to this along with

in-text art while performing troubleshooting.

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