Aircraft Runup PDF

Aircraft Runup Ground Run: - Wipers are kept off - If left on, it might scratch the windshield - If that happens, the plane is not allowed to take off. - Remember to turn off wipers before starting up - Always use water when testing the wiper to prevent friction from...

Aircraft Runup Ground Run: - Wipers are kept off - If left on, it might scratch the windshield - If that happens, the plane is not allowed to take off. - Remember to turn off wipers before starting up - Always use water when testing the wiper to prevent friction from scratching the windshield. - Start the master switch, then wait 90 seconds then start - The battery voltmeter must be 24 volts, otherwise the plane won't start - APU fire piston: - Fire detection system - Uses four light bulbs to ensure the fire distinguishers are discharged, providing fire protection for the APU. - Overhead scan - Scans to make sure everything is working. - Ground run enclosure - A half pipe is used to prevent the air from generating a lot of heat onto whatever is behind it. - Story - Brand new airbus 340 was destroyed 2 days after production was complete. - Flight crew conducted pre-delivery tests on the ground - One person pulled something that automatically removed the brakes, causing the plane to crash into the enclosure - 200 million dollars of work had been lost as a result. A modern jet engine can roll over a car driving 50 yards behind it Aircraft Engine Ground Run -- Jet Blast - At full power exhaust wake speeds can typically be 130 to 240 km/h. - Exhaust speeds can reach 300 km/h - A category 1 hurricane for comparison reaches speeds of 115 to 130 km/h. - Power hazard areas - Power hazard areas are located aft of the engine exhausts, and - When modern jet engines are operated at rated thrust levels, the exhaust wake can exceed 375 miles per hour (603.504 kilometers per hour) - An idling airplane can produce a compact version of a category 3 hurricane, with an engine wake approaching 120 miles per hour. - At extreme end of the intensity scale is a category 5 hurricane, - With wind greater than 155 miles per hour. - Residential, industrial structures would experience roof failure, with lower strength structures experiencing complete collapse, - If you are doing a ground run, make sure the blast fence or ground run enclosure. is high enough to cover that. Noise - Jet engines produce a lot of noise - So much so that the city of Toronto put a curfew on flights after 11 - Whilst engines have gotten better, the blast is still there, though the noise has gotten quieter. - Regulating noise is a challenge because of the\... - local geography, - proximity of residential developments - and complex sound characteristics from the noise source. - Jet engines have a noise footprint at takeoff of 120 decibels Positioning - Aircraft should be positioned away from other people, hangars, shops or other vehicles - Aircraft shall never taxi behind other aircraft in the process of an engine run-up. - All engine run-ups need to be authorized by control towers. - Because of these factors, it's possible to not have an engine runup for the whole day. - Fire protection should be available at all time - An FOD check should be done before a runup to avoid foreign objects from getting sucked up into the engines Flight deck management - A licensed AME on type will be in the left seat (in command) - A second AME will be in the right seat to ride the brakes and keep a watch on the outside the aircraft. - **Ground Command:** A third mechanic will be on the ground to have a full view of the outside of the airplane. - **Fire Extinguisher Command:** A fourth and fifth mechanic will be positioned by the fire extinguisher on the left side of the aircraft whilst in full view of the third mechanic, but out of the way if the aircraft jumps the brakes - **Tail Watchers:** the sixth and seventh mechanics will be positioned to prevent entrance of vehicles into the run-up area. - The flight deck and all the ground crew will have walkie talkies to have 24/7 communication. - The tower will give permission for the run - One flight deck radio will be tuned for the airport emergency frequency. - **Every ground run needs a minimum of 5 people.** Low Power Runs - **Purpose:** Fuel leaks, checks, oil and hydraulic filters, replacement components, engine overhaul, etc. - Note: the term "idle power" for the purpose of this procedure is the lowest percentage of power at which the engine will run with throttles fully retarded (retracted full back). - Permission to do LPR is granted if there is confirmation that the engine will only run at idle. - Only one plane is allowed to do engine runs at a time PPE - Mechanics are required to do an FOD check of their pockets to get rid of hats or anything that can fall or get sucked into the engine. - Wheel chocks may or may not be used depending on the AME's steering strategy if the aircraft brake let go - CONCENTRATE, CONCENTRATE, FOCUS, FOCUS, FOCUS - Only carry tools you need and count them before and after - No Loose clothing or long hair - Know your environment **How do engines start:** 1. Start command with cockpit 2. Electrical power (via battery) 3. Electric starter motor 4. APU 5. Starting air a. Air is drawn in through the compressor blades of the turbine engine. b. The engine is let to run until the necessary RPM is reached. c. Every blade goes through the spark plugs until the necessary RPM is reached. **Components for starting the engine:** - APU - Air turbine starter - Ignition - Clutch - Connected to the air turbine starter - Stage 1: Fully engaged - Stage 2: Partially engaged - Stage 3: Fully disengaged **Engine Test Run** 1. Idle check for oil, fuel and component replacement 2. Full power according to barometric conditions, a. Slowly advance both engines to 50%. This prevents the airframe from twisting with the thrust if one engine is at idle and the other is at full power. b. Advance one engine to chart full power slowly, then take readings and slowly back at 50%. c. Repeat with the other engine. Slowly retard throttle to idle 3. Slam (not actually) one throttle ahead and count 7 seconds to spool up to target number on chart; This process is for acceleration check 4. Bleed air check; checks where engine bleed valves close as power increases 5. Vibration check; done at higher power to ensure first stage compressor blades are balanced. 6. Five-minute cool down 7. Engines off **Turbine Heat Management** - The turbine engine expands and contracts with heat with very small and critical dimensional tolerances - The engine must be temperature stabilized "warmed up" and throttle movements are done - All throttle movements must be done slowly to lessen the thermal shock of increased fuel and resultant heat through the hot section core. - After all the checks are done the engines have to cool for 5 minutes before shut-down. - Tip clearances between the turbine blades and the shrouds covering them are very susceptible to blade contraction with quick temperature\... throttle movements or shutting the engine down while it is hot and not stabilized in temperature. **Piston Engine Temperature and Manifold Pressure Management** 1. Engine oil temperature must be in the green 2. Throttle movements must be slow as manifold pressure and temperature increases 3. Rapid change of manifold pressure will reduce life of the engine, and it's changes of making its TBO 4. Mechanics must be extra careful of the propeller when doing engine leaks checks 5. Special goggles should be worn because of the dust blown back by the propeller