C-5 Auxiliary Power Unit (APU) Practice Test

These questions are part of the practice quiz. Start practicing

• Which condition can negatively impact the lubrication system of an APU?
• When is it permissible for a ground observer to fight a fire related to the APU?
• What does an illuminated fault light on the cockpit panel indicate regarding the APU?
• How does an APU contribute to overall aircraft weight?
• How often does the C-5 APU typically require major overhauls?
• What is one disadvantage of ventilating the APU in an enclosed area?
• What does the term “single-point fueling” refer to in context with the APU?
• What is the recommended state of the APU during aircraft taxiing?
• Which system does the C-5 APU primarily support for temperature regulation and comfort?
• How many minutes are required to fully recharge the APU start accumulators?
• If the APU generator fail light comes on during operation, what is the appropriate course of action?
• Why must you wait five seconds before turning off the battery switch after pulling the APU fire handle?
• Why is maintenance critical to the performance of the APU?
• Which of the following is NOT a safety feature of the C-5 APU?
• What is a common troubleshooting step if the APU fails to start?
• How is the APU control typically activated or deactivated?
• How does the APU assist in aircraft engine starting?
• Which cockpit indicators are relevant to APU operation?
• Does an EGT reading of 716-824°C during APU start indicate a malfunction?
• What indicates that the APU is ready to supply electrical power?
• What happens if the APU is operated under certain conditions with the aircraft on jacks?
• What is the EGT range for continuous full load APU operation?
• Which of the following is a safety precaution during APU maintenance?
• Which system helps maintain fuel quality in the APU?
• What is a required preflight check for the APU?
• How many feet must one hangar door be opened, and what is the purpose?
• What happens if the APU experiences excessive speed?
• What routine maintenance tasks are necessary to ensure the APU's longevity?
• What indicates that an APU fire has occurred during operation?
• What is the minimum hydraulic pressure required during ATM operations?
• What does the APU require in terms of accumulator pressure for a normal start?
• What type of fuel does the C-5 APU use?
• What is the approximate fuel consumption rate of the C-5 APU?
• What could an APU temperature warning light indicate?
• What is a consequence of an APU operating in extreme temperatures?
• What must occur to abort the APU start if a fuel leak is detected?
• What is the maximum operational altitude for the C-5 APU?
• What can contribute to the APU not starting?
• What must be done with the BOTTLE SELECT switch during an APU emergency?
• How long can the C-5 APU operate continuously under normal conditions?
• What is the primary purpose of the APU's air start capability?
• How does temperature affect APU performance?
• What does the APU provide to ensure effective engine starting?
• What happens when the AIR COND switch is in the BOTH position?
• In the absence of core processing, communication with Ground Control/Control Tower should use which system?
• How should the bottle select switch be positioned for APU emergency controls?
• What PSI should SYS 1 and/or SYS 4 indicate during operation?
• What type of engine powers the APU in the C-5?
• Why is it crucial to monitor APU oil temperatures?
• What is the maximum continuous EGT for operated APU?
• What is the minimum amount of fuel required in MAIN Tanks 2 and 3 for the operation of APU/ATM systems?
• Which component of the APU system is critical for managing its operations?
• What is the primary role of the APU before takeoff?
• What might occur if safety precautions are not followed during APU maintenance?
• What is the main advantage of using an APU during flight preparation?
• Why is it essential to monitor oil temperature in relation to the APU?
• What function does the APU serve during periods when the aircraft is stationary?
• What is the relevance of the APU's bleed air in pressurization?
• Which of the following can lead to operational failures in an APU?
• What is a common cause of failure in the APU?
• What is the APU's maximum start time from the start light to "ON SPEED" at 0°F and above?
• In which position must the battery switch be for a fire handle shutdown?
• What role does the APU play during aircraft ground operations?
• Where is the APU located on the C-5 aircraft?
• What maintenance practice can help prevent APU overheating?
• What is the initial sequence of system checks performed after starting the APU?
• What safety feature prevents the APU from starting if the temperature is too low?
• How does an APU generally support the aircraft's systems?
• How does the APU control panel indicate that the unit is operational?
• What is one of the APU's primary outputs for supporting ground operations?
• What does TO 1C-5-714 modify?
• Which alert is indicated by the APU fire light on the pilot's enunciator panel?
• What does an "APU Fault" light indicate?
• What role does regular maintenance play in APU performance?
• What kind of system is integrated with the APU?
• What does a transient temperature of 715°C to 824°C require?
• What is a significant indicator of APU performance issues?
• What is the consequence of neglecting APU maintenance?
• What hazard is associated with APU exhaust?
• Before starting the C-5 APU, what is crucial to check?
• What should be disconnected from the A/C prior to operation of either ATM?
• How often should the operational parameters of the APU be monitored?
• Which feature of the APU increases its operational reliability?
• Where should the qualified APU operator be located during operation?
• Which of the following can cause an APU to shut down unexpectedly?
• What action should be taken after notifying Ground Control about an APU emergency?
• What systems are powered directly by the APU?
• When is the APU required to be utilized without exception?
• Which of the following is NOT a BOLD FACE ITEM in emergency procedures?
• What type of fuel does the C-5 APU utilize?
• What is the consequence of not allowing the APU appropriate warm-up time before applying an air load?
• Which indicators are crucial for monitoring APU performance during flight?
• Under what condition can the Electric Suction Boost pumps be shut off while operating hydraulic systems?
• Under what circumstances is it mandatory for the APU to be operational during ground operations?
• On the loadmaster panel, where should the APU emergency controls be set?
• What is involved in the starting sequence of the C-5 APU?
• How is the APU's fuel system designed to operate?
• What is the main advantage of the APU for military aircraft like the C-5?
• What action must be taken by the fire guard after APU fuel/oil system maintenance?
• What type of engine design does the C-5 APU utilize?
• Where are the APU fire extinguisher bottle select switches located?
• What procedure is followed to ensure the APU is serviceable?
• Where are the APU fire extinguisher bottles located on the aircraft?
• What are the typical operating limits monitored for the C-5 APU?
• What is the indication required from the AC load meter on the AC SYS CONTROL PANEL?
• What does the APU indicator light signify in the cockpit?
• What may occur if the APU fuel filter becomes clogged?
• What indication signals that the APU is ready for use?
• What is one of the primary functions of the APU during ground operations?
• What is one of the primary purposes of an APU?
• How does the APU contribute to environmental control in the aircraft?
• What is the ideal time to wait after the APU has reached operational temperature before starting the unit?
• What action should be taken if the EGT exceeds 715°C during APU start?
• How long should the APU be warmed up before applying an air load?
• How does the APU relate to an aircraft's maintenance schedule?
• Why is proper ventilation necessary when using the APU?
• What sequence of operations occurs when starting the APU?
• What is the minimum pressure for the left and right APU start accumulators?
• During an APU emergency, which procedure should be prioritized first?
• How often should the oil in the C-5 APU be checked?
• What safety feature in the C-5 APU helps prevent excessive speeds?
• What indicates a malfunction if starting the APU?
• What is the significance of APU RPM readings in the cockpit?
• What type of power does the APU generator typically generate?
• Which type of oil is used in the C-5 APU?
• Which tools are essential for APU maintenance troubleshooting?
• What should the AC volt meter indicate on the AC SYS CONTROL PANEL?
• What happens if the APU fails during operation?
• At what temperature does APU's maximum start time increase to 60 seconds?
• How does the APU maintain its operational efficiency?
• What action should be taken if irregular fluctuations in APU performance are detected?
• What should be factored into flight planning related to the APU?
• What is the acceptable range indicated by the FREQ meter on the AC SYS CONTROL PANEL?
• What is the operational capacity of the C-5 APU in terms of power generation?
• In what situation is the APU most critical for aircraft operations?
• What does the term "bleed air" refer to in relation to the APU?
• What role does the APU play while the aircraft is on the ground?
• During an APU operation, why is monitoring the audible APU fire warning system important?
• What may trigger the APU fault light to illuminate?
• What key feature enhances the operational capability of the C-5 APU?
• Which action is crucial to ensure APU reliability?
• To which frequency should the UHF/VHF radios be set during operation?
• What component prevents APU fuel starvation?
• What is the loss in PSI through each power transfer between hydraulic systems?
• What should be done if the APU oil pressure is low during operation?
• How is APU maintenance tracked on the C-5?
• What is the best practice when an "APU Fault" light is illuminated?
• What responsibility does the fire guard have during APU operation?
• What is the purpose of the APU's fuel management system?
• What functionality does the APU control panel provide?
• What happens if there is a fuel supply interruption to the APU?
• Which of the following tasks does the APU NOT perform?
• How can a fire extinguisher be discharged into the APU compartment if the APU fire extinguisher bottle does not extinguish the fire?
• What is the significance of an APU's control module?
• How can the operational efficiency of an APU be maximized?
• Transitioning from external power to APU power may cause which system to fail?
• Why is the APU essential during engine starts?
• What must personnel do when operational parameters are not met during ATM operations?
• How does the APU contribute to crew comfort during ground operations?
• What is necessary when operating the APU with the APU compartment door open?
• Which hydraulic systems are used to pressurize the APU accumulators?
• During the start of an ATM, what is the time limit for hydraulic pressure to reach the operating range?
• When starting ATM/PTU, why is it important to check the position of the flaps/slats with a ground observer?
• What is a potential consequence of neglecting APU maintenance?
• What type of tests are conducted on the APU during maintenance?
• When does a "Full Load" condition occur?
• For cooling purposes, how long should the APU run unloaded before shut down?
• Which of the following is a primary indicator of oil quality in the APU?
• What is the primary function of the C-5 APU?
• What is the first step in shutting down the C-5 APU?
• What actions should be taken if either battery is below the minimum voltage?
• What is the consequence of having an unserviceable battery installed and connected?
• Which components are included in the C-5 APU system?
• If the APU is started without external power, what indication will be absent?
• What is a common indicator of needing APU maintenance?
• How does the APU contribute to fuel efficiency during ground operations?
• What happens if the elapsed time of 30 seconds to ON SPEED is exceeded during APU start?
• What should be minimized to enhance APU operational efficiency?
• What safety measure prevents APU overspeed?
• What can result from an APU start accumulator charged to less than 2800 PSI?
• What is one of the primary causes of wear and tear on an APU?
• How does the APU provide benefits to aircraft operations?
• What role does the APU play during high-temperature ground operations?
• Why is regular maintenance critical for APUs?
• What mechanism is employed to prevent over-temperature conditions in the APU?
• What is the primary function of the C-5 APU?
• What is the typical cycle time for an APU's start and cool down?
• What happens when the APU reaches self-sustaining speed during the starting process?
• What component allows the APU to shut down automatically under specific conditions?
• How does environmental temperature affect APU performance?
• Which buses will be powered when APU generators supply aircraft power?
• What is the purpose of ensuring the APU emergency controls are in the correct position?
• Which of the following is NOT a maintenance task for the APU?
• How do temperature extremes affect APU function?
• What is the maximum altitude at which the C-5 APU can operate?
• How is the APU cooled during operation?
• Why is it necessary to monitor APU exhaust temperatures?
• What information is provided by the APU run time data display?
• What should the DC volts meter indicate during operation?
• What is the primary function of the APU's lubrication system?
• In what scenario might external power sources be preferable over the APU?
• How often should APU oil levels be checked?
• How can the APU impact ground operations?
• What type of electrical output is provided by the APU?
• During which state must a qualified operator monitor ATM operations?
• What component monitors the APU's oil pressure?
• What is the minimum battery voltage required?
• What must be done to protect personnel from APU exhaust hazards?
• How is the APU's fuel system protected against contamination?
• In what situation would you likely keep the APU on during taxing?
• In terms of electrical power during ground time, what role does the APU play?
• If pressure gauges are not steady, what is the first action to take?
• Which of the following can be described as a primary function of the APU?
• What is the typical maintenance schedule for the C-5 APU based on?
• During what circumstances does the APU need to provide cooling air?
• Why is it important to allow the APU to cool down before shutting off the fuel supply?
• What must be available when starting an APU without external power?
• Which system is responsible for alerting the crew of APU malfunctions during flight?
• What is a potential consequence of not maintaining proper distance from APU exhaust?
• What are the two primary systems the C-5 APU supports?
• What adverse effect can improper usage of an APU have on fuel consumption?
• What is the role of the APU control panel in the C-5?
• Why is it important to monitor the APU's operation through its control panel?
• What factor can lead to increased fuel consumption in an APU?
• If a complete loss of hydraulic pressure occurs during ATM operation, what is the recommended action?
• What must be accomplished if there is no external power available for an APU start?
• What is the maximum transient limit for EGT during APU start?
• What could a malfunctioning fuel filter lead to?
• What is the maximum duration for the transient EGT between 715°C and 824°C during APU start?
• Which of the following is an effect of insufficient cooling on an APU?
• Where must personnel be stationed during the operation of ATMs?
• What does the pressure gauge indicate when it is unstable?
• Can the C-5 APU operate silently?
• Before pressurizing the No. 2 and No. 3 hydraulic systems, what should be set on the INBD ELEVATOR panel?
• What is the correct range for EGT during normal APU starting conditions?
• How does starting the APU affect the main engine start sequence?
• What is required when operating the APU/ATM system in hangars without an automatic fire suppression system?
• What is the main purpose of the APU's exhaust system?
• What is one of the key benefits of having an APU on large aircraft like the C-5?
• When should technicians perform an APU oil change?
• What is the maximum EGT upon applying load at governed speed?
• How does the APU affect the weight and balance of the aircraft?
• How can the pilot manually initiate a shutdown of the APU?
• During APU startup, what position must the battery switch be in and why?
• Which component of the APU is responsible for generating electrical power?
• What is TO 1C-5-736 primarily used for?
• What should a crew do if the APU fails to start?
• How many seconds should you leave the APU/OFF/EXT PWR switch in the 'off' position before switching to APU?