Flashcards in UH 60 Start System Description 1 Deck (71)
Discribe the UH60 engine start system
The engine start system is an electro-pneumatic system used to start both engines.
What is the caution that pertains to moving the engine PCL while pressing the starter button
To aviod damage to the engine start switch actuators, do not mover the EPCL from IDLE to OFF while pressing the starter button
What is the auto start circut?
During acceleration to idle, a speed sensor on the starter feeds the Ng speed information to the speed switch
The speed switch commands the starter valve to open until the Ng speed reaches a minimum of what % NG
Between __% and __% NG the start valve will close extinguishing the starter caution light.
How does a pilot abort an auto start sequence?
By pulling down on the PCL. This actuates the abort start switch and closes the starter air valve.
How does a pilot complete a manual start?
By pressing and holding the starter button during the start process, and releasing the button when the NG speed reaches a minimum of 52% NG.
What are 3 ways to provide air for Engine Starts
APU, Crossbleed, Ground Source.
What does the APU do for the engine start?
The APU supplies air to the engine selected for engine start. (turbomach and Garrett are the two types of APUS.)
Can an Engine start be accomplished with the APU air source availalble but NO AC power from the APU Gen?
Yes, If the battery is the sole source of DC power, and an air source is available( i.e. the APU available, but the APU gen is inop), only the #1 engine may be started.
What is the #1 engine start valve powered by?
The #1 engine start valve is powered by the DC essential bus, and no instruments will operate until the AC power becomes available.
What is the #2 enigine start valve powered by?
The #2 engine start vavle is powered by the #2 primary bus, and requireds an operaitonal main or APU gen, or and external power source.
What happens when a pilot presses the #1 engine starter button?
Pressing the #1 engine starter button opens the #1 engine start valve, allowing air supplied by the APU to enter the #1 starter and the #1 Engine.
What valve is utilized to complete a cross bleed start?
Cross bleed starting utilizes the bleed-air shutoff vavle to direct air from the operating engine to the opposite engine during the start sequence. Starting one engine from the other (cross bleed start) is the same as starting an engine using the APU as the air source, except the AIR SOURCE HEAT/START switch will be in the ENG position.
During a Cross bleed start, were does the pressure come from to start the other engine.
Pressure from the running engine compressor is used to start the other engine.
What are the requirments to accomplish a Cross Bleed start?
To accomplish a Cross Bleed Start, the running engine should be at 90% NG with the RPMR at 100%, and the engine anti-Ice advisory light off.
During a crossbleed start why might you have to raise the collective?
The collective may have to be raised to increase the NG to 90% as an 18% loss of the Maximum TQ available on the air source engine will be experienced during the start sequence.
Why would you want to use the APU during an in flight engine start?
A cross bleed start in flight may decrease the max TQ available from the running engine by as much as 18%. Therefore, the APU should be used.
What is an AGPU used for?
The AGPU is an external air source used for engine starting.
What are 2 sources of external engine starts?
Aircraft to Aircraft (buddy Start) and AGPU
Where does the pneutic tubing start and end?
The pneumatic tubing and manifold used during the engine start sequence, extends from the left side of the transmission sectoin throughout the cabin suction upper deck area forward to the heater.
What is the first section of the pneumatic tubing and what does it do?
The first seciton of the pneumatic tubing is the nipple check valve. The nipple check vavle provides a connection point for external air source.
Name all of the sections of pneumatic tubing in sequence.
Lower tube, middle tube, upper tube, front tube, cross bleed tube, and the APU compartment front tube connects to the cross bleed tube.
Discribe the Pneumatic tubing.
The pneumatic tubing consists of a series of coupled or welded tubes joined together so any one of the air sources may provide bleed air for whatever reason depending on demend.
Discribe the pneumatic system.
The pneumantic system is comprised of a series of tubing and valves that distribute compressed air to bleed air dependant systems.
Pneumatic tubing is not allowed any dents that exceed __% of the total diameter of the tube in question.
Are cracks allowed on pneumatic tubes or joints?
Where are the starter contol Valves located
the start control valves are located inside the oil cooler compartment, inboard of each respective engines firewall.
The start control valves are _______ controled and ___ ______ to allow bleed air to flow through to the engine starter.
The start control valves are electrically controlled and air actuated to allow bleed air to flow through to the engine starter.