munirabbasi Posted December 14, 2020 Share Posted December 14, 2020 Hello Herks Hydra Expertise! B model aircraft,During Retraction cycle of landing gears with UT system (in-flight) low pressure WX light of UT suction boost pump was Flickered and extinguished when gears were up and locked. Manufacture of Suction pump is able corporation sealed type and without cooling FAN and also without modification (C-130E airplanes AF72-1288 and up and C-13OH airplanes have a suction boost by-pass circuit. The by-pass line contains a restrictor and a check valve that will continuously circulate one GPM of fluid, from the suction boost pump back to the booster system reservoir, to provide a cooler operating boost pump). FE Said operation of LDG were not conducted along with FLAP ops simultaneously. any expert opinion Munir Abbasi Home Hercules Pakistan Quote Link to comment Share on other sites More sharing options...
hehe Posted December 14, 2020 Share Posted December 14, 2020 Is this the same aircraft that was having these issues? There was a post about a week ago with similar issues Previous history of this? Any recent maintenance done? I wouldn't automatically call it bad if it just flickered. It could be a loose cannon plug on the low press switch and the gear going up shook the wall. It could just be a loose push to test on the warning light. What has been done to resolve? Quote Link to comment Share on other sites More sharing options...
munirabbasi Posted December 15, 2020 Author Share Posted December 15, 2020 3 hours ago, hehe said: Is this the same aircraft that was having these issues? There was a post about a week ago with similar issues Previous history of this? Any recent maintenance done? I wouldn't automatically call it bad if it just flickered. It could be a loose cannon plug on the low press switch and the gear going up shook the wall. It could just be a loose push to test on the warning light. What has been done to resolve? No and No previous history of hydraulic defect or maintenance regrading hydraulic system. Low PRESS WX SW connector was checked found SAT . wiring security and circuit checked found SAT . Defect could not duplicate on ground. Best Regards Munir Abbasi Home Hercule4s Pakistan Quote Link to comment Share on other sites More sharing options...
hehe Posted December 15, 2020 Share Posted December 15, 2020 Check the simple things Util reservoir filters (pressure return/case drains and reservoir vemt filter). Something as simple as a wet vent filter can cause enough of a liquid lock that pump would cavitate during large draw such as landing gear movement. Swap the low pressure switch to booster side. See if it follows the switch to booster side. Check the landing gear flow regulators. Should be free flow toward motor and regulated away on both up/down lines. What was the util system pressure drop? Did it drop below or around 1300 psi? Quote Link to comment Share on other sites More sharing options...
munirabbasi Posted December 15, 2020 Author Share Posted December 15, 2020 9 hours ago, hehe said: Check the simple things Util reservoir filters (pressure return/case drains and reservoir vemt filter). Something as simple as a wet vent filter can cause enough of a liquid lock that pump would cavitate during large draw such as landing gear movement. Swap the low pressure switch to booster side. See if it follows the switch to booster side. Check the landing gear flow regulators. Should be free flow toward motor and regulated away on both up/down lines. What was the util system pressure drop? Did it drop below or around 1300 psi? Thanks for immediate response Oh! Teflon hose , mounted bottom of utility system reservoir was found kinked Quote Link to comment Share on other sites More sharing options...
munirabbasi Posted December 15, 2020 Author Share Posted December 15, 2020 10 hours ago, hehe said: Check the simple things Util reservoir filters (pressure return/case drains and reservoir vemt filter). Something as simple as a wet vent filter can cause enough of a liquid lock that pump would cavitate during large draw such as landing gear movement. Swap the low pressure switch to booster side. See if it follows the switch to booster side. Check the landing gear flow regulators. Should be free flow toward motor and regulated away on both up/down lines. What was the util system pressure drop? Did it drop below or around 1300 psi? Thanks for immediate response Oh! Flexible hose, mounted bottom of reservoir was found Collapsed Munir Abbasi 10 hours ago, hehe said: Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.