EFTA Document EFTA01781557

From: Larry Visoski Sent: Sunday, April 1 , 1 11:1 To: Subject: Je vacation GIV update Jeffrey Message from Pete,.below: Dave and I are at airport now in case=you decide to depart earlier than 3.0am„ I suspect that the right precooler (fan air) modulating valve i= bad. They are both original. From the last video and Photo's; The readings show th=t the left side is being given a voltage to the Torque motor sending a=nbsp;pressure to command the valve to be partially closed. Zero volts, zero pressure is for full open, ie: co=d air into the precooler and lowering the temperature into the supply syste=. There is no signal from the valve, the temperature monitoring circuit cont=ols the changes required. The right side shows that it is bein= commanded to close due to the high voltage, and pressures. ( 9 volts, 9 PSI) It seems that the signals are not being followed, or that the val=e cannot respond to them. Since t=e control system does not see the temperature change from the sensors, it c=ntinues to increase the pressure to the valve. Brief complete•=/span> EFTA_R1_00100605 EFTA01781557 As for the full version- This was done as a draft, please excuse any duplication for items noted i= the brief, these were my original thoughts. I agree with all t=at you stated- =span style="background-color: rgba(255, 255, 255, 0);">The guidelines are=for what the electrical system does. We have found a bad controller- the sweeping voltage and pressures, and r=placed it- There was also a bad s=nsor that was replaced- We have s=apped the pressure regulator/torque motors. Latest swap was the Anticipators. There seem to be multiple issues, and we are narrowing them down.=/span> I believe that the electrical and=control systems are now operating normally. Now on to the air side of it. From the last video,=and photo's- I believe that the l=ft side is operating properly. Th= Temp is being controlled by sending a regulated pressure to the valve, and=it responding. =span style="background-color: rgba(255, 255, 255, 0);">The pressure suppl=ed is closing the valve, and maintaining the 400 Degrees requested.<=p> No voltage equals no pressure, Valve open= lowering the Temperature. </=pan> The right side shows giving a close=signal to the precooler (fan air) valve. High Voltage, and pressure supplied to the Valve on that side to dos., and increase the temperature. T=at side doesn't seem to respond. =he valve has a 4 inch input/output side. 2 EFTA_R1_00100606 EFTA01781558 The control line is about 1/4 inch. That is one of the lines that we found collapsed, and started us on=this direction. Is it possible that the supply air is not bein= able to overcome the pressure at the valve? The pressure read at the panel is a control pressure, also known=as "Muscle air". Maybe the input a=r at the 4 inch diameter inlet, can overcome the control air. I again suspect an issue with the LP valve- There is no valve position, or feedback signal from the valve- The electrical signal is showing to cl=se the valve, <=pan style="background-color: rgba(255, 255, 255, 0);">The pressure is als= showing to close the valve. =/span> One way to check is to select Win= heat on- The system causes the a=plicable side to remove the signals, and allow the valves to go full open.<=span> Wing heat is not normally used at a=titude- When the aircraft is in b=low 0 degrees temps, there is no reason, since any precip won't stick. Ask Larry if there any issues with sel=cting the wing heat on at altitude- I don't believe that there are any limits to the altitude, but the fuel bu=n will be increased. Just a quick check- The groun= checks for the precooler system are limited, Engines running, there should be no air flowing from the lower p=Ion heat exchanger at idle- Incre=se power, and there should be airflow noticed. 3 EFTA_R1_00100607 EFTA01781559 My training manual shows that the valve should start to open a= about 74% HP on the ground, Wing=heat on, there should be airflow. Regards, Pete Sent from my iPhone = 4 EFTA_R1_00100608 EFTA01781560