Chp 4 ( Ground Running) Flashcards
What is engine ground running?
Engine ground running is the process of running aero-engines without flying the aircraft, crucial for aviation maintenance.
Why is ground running important?
Ground running allows for extensive testing on the ground, minimizing the risk to life compared to in-flight testing.
What procedures should be followed during ground running?
Aero-engine and APU ground running must be conducted according to the relevant technical information and Local Orders.
What is the role of the ground running supervisor?
The ground running supervisor ensures that all team members are briefed on their responsibilities and the general procedures.
What is a typical composition of a ground running team?
A typical team may consist of a
-Supervisor
-Operator
-Safety Person.
What additional member is usually present in helicopter ground running?
Helicopters typically have a pilot as the operator due to the risk of ‘Ground Resonance’ during the run.
What poses a danger to crew and maintenance personnel in helicopters?
The engine and rotors pose a danger once installed into the airframe.
What is the first drill to follow when approaching a helicopter with turning rotors?
Always give the thumbs up signal before entering or leaving the rotor disc.
What should you wait for before entering or leaving the rotor disc?
Never enter or leave the rotor disc until the pilot returns the thumbs up signal.
From which position should you enter and leave the rotor disc?
Enter and leave from the correct place; 12 - 2 o’clock is ideal.
What should be done with headdress and loose clothing/items when near the rotor disc?
Ensure headdress and loose clothing/items are removed or secured.
When should you never enter the rotor disc?
Never enter the rotor disc whilst the rotors are running up or slowing down.
What is blade sailing?
At low rotor RPM and gusty wind conditions, the blades may suddenly drop below head height.
What is the danger of the tail rotor?
The tail rotor is extremely dangerous; it is smaller and rotates at a much higher RPM than the main rotor.
What is the rule regarding walking near the tail rotor?
NEVER walk near or around the tail rotor.
What do engine air intakes create when running?
Engine air intakes create a large depression, resulting in high air velocities.
What are the dangers of engine exhaust?
Exhaust gases are extremely hot and will cause burns; they are also poisonous.
What do the shaded areas in the aircraft documentation indicate?
The shaded areas show the most dangerous areas when the engines are in operation.
What should you be careful of when working near danger areas?
You must be careful when you do work in or near the danger areas. Obey the precautions that follow.
When is it necessary to go near the main or tail rotor blades?
Do not go near the main or tail rotor blades when an engine is in operation unless it is necessary.
What should you do if you need to go near the aircraft?
Get approval from the person who operates the engine.
From which position should you enter the area below the rotor disc?
Only go into the area below the rotor disc from the forward right hand side (starboard) position.
What is important to ensure when near the aircraft?
Make sure the person who operates the engine can see you.
What should you keep away from when an engine is in operation?
Keep away from the engine intake and the exhaust area when an engine is in operation.
What are some reasons for ground running?
The reasons for ground running include:
- Testing of engines after installation (leak checks, set up parameters)
- Testing of engines after major component change
- Testing engine driven systems (Accessory Drives etc.)
- Carry out preventive maintenance
- Verify faults
What should be ascertained for safety constraints regarding aircraft?
The danger zones for the aircraft type, found in the maintenance manuals.
What must be ensured regarding outstanding work on the aircraft?
There is no outstanding work being carried out on the aircraft.
What should be checked regarding oils and lubricants?
All oils and lubricants should be topped up.
What should be checked about the aircraft’s surroundings?
The aircraft should be well clear of buildings and there should be no FOD in the area.
In which direction should the aircraft be facing?
The aircraft should be facing into the wind.
What is required for wheeled aircraft?
Chocks should be in place for wheeled aircraft.
What should be ensured about the aircraft panels?
All panels should be fitted and closed unless required to be open for access during the run.
What type of fire extinguishers should be positioned?
Fire extinguishers of the correct type should be positioned.
What should be checked regarding the safetyman?
There should be a safetyman in communication with the pilot/operator.
What personal protective equipment should be worn?
Ear protection should be worn.
What should be ensured about personnel during engine running?
All personnel should be kept clear of the aircraft whilst it is running.
What will the pilot/operator check prior to start?
The pilot/operator will check to see that all personnel are clear.
What is a Wet Start?
Residual fuel remaining in the combustion chamber following an attempt to start with no subsequent ignition.
What is a Vent Run?
Motor the engine over using the starter motor with no ignition or fuel. The compressor air will blow any residual fuel out of the system.
What is a Drying out Run?
A full engine run carried out after a compressor wash to remove residual water/ZOK mixture while drying the engine out, thus preventing corrosion.
What are Dry Runs?
Similar to a vent run (Dry Crank).
What is Stagnation (Hung Start)?
Engine hangs up during start-up and does not accelerate. Possible causes include fuel starvation.
What is a Hot Start?
Turbine temperature rises to a level above the temperature allowed for engine starting in the AMM. H.P. cock should be immediately closed and the reason identified.
What is Run-down Time?
A timed check, from closing of the HP Cock, to the engine stopping (IAW AMM).
What is the typical sequence for a Run Down Time Check?
- Close HP Cock
- Start stopwatch
- Time engine until rotation ceases
- Check time against the aircraft maintenance manual (AMM)
- This is an indication of engine condition
- Carried out by the pilot (or engine operator after ground run engine shut down)
How should emergencies be handled during engine operation?
Any emergencies that occur prior to, or after the engine has achieved self-sustaining RPM, are to be dealt with in accordance with the relevant technical manual instructions for that engine or aircraft installation.
What is the International Standard Atmosphere (ISA)?
The ISA was established by the International Civil Aviation Organisation as a uniform reference for temperature and pressure, derived from average conditions at all latitudes, seasons, and altitudes.
What are the standard conditions for ISA?
ISA is related to sea level at 45 degrees latitude with zero humidity, giving a temperature of 15 degrees Celsius and a barometric pressure of 1013.25 millibars.
Why is ISA correction necessary during engine testing?
Changes in Outside Air Temperature (O.A.T.) and local air pressure occur with different altitude and climatic conditions, necessitating adjustments to compare performance of similar engines or ensure power outputs are within tolerances.
How are ISA corrections carried out?
Once the data that needs to be corrected and the ambient conditions during the run are known, ISA corrections can be made. Older generations of aircraft use a chart or graph found in the maintenance manual.
What is the process for using a chart for ISA correction?
The chart used to correct observed data into its ISA corrected equivalent is provided by the engine manufacturer. Figures are plotted, and a line is drawn to intersect with the ISA reference line, allowing the corrected figure to be read off.
What is more common today for calculations in aviation?
Using a scientific calculator or a computer is more common today for calculations in aviation.
This method is more accurate than plotting lines on a chart.
What capability do some modern aircraft systems have regarding ISA corrections?
Some modern aircraft systems can make ISA corrections using on-board computers.
What is needed after making ISA corrections to observed data?
A datum to compare the ISA corrected data against is needed.
How can ISA corrected figures be compared?
ISA corrected figures can be compared against nominal figures for all engines of that type or against figures established by the manufacturer for that particular engine.
What is Placard Data?
Placard Data is the reference data recorded from engine tests, used for future performance assessments.
Where is Placard Data recorded?
Placard Data can be recorded in the engine log book, the F700 for the aircraft, or printed on tape next to the appropriate gauge in the cockpit.
What does Placard Data provide to pilots?
Placard Data provides pilots with a set of ‘minimums’ or performance figures that must be attained prior to take-off.
What must pilots do with Placard Data?
Pilots must carry out their own correction to convert the placard figures back to the expected figures under prevailing atmospheric conditions.
How can engineers use Placard Data?
Engineers use Placard Data as a datum to compare future performance runs, identifying any deviations that may indicate wear or deterioration.
What problem can low air temperature cause for engines?
Low air temperature can cause an engine to approach its operating limitations, presenting a challenge for engine designers.
How did older engine designs accommodate low temperatures?
Older engines were designed with safety margins to prevent overstress due to low temperatures, which limited their performance.
What advantage do FADEC systems provide?
FADEC systems adjust fuel systems based on air temperature and pressure data, allowing engines to operate with reduced safety margins for better performance.
What is Flat Rating in turbine engines?
Flat Rating means that an engine is capable of producing more power under ISA conditions than the pilot is allowed to use under higher temperatures or elevations.
What limits turbine engine power output?
The maximum power output of a turbine engine is limited by the temperature the combustion system and turbine components can resist.
What conditions define ISA for turbine engines?
ISA conditions are defined as 15°C air temperature at 1013.25 millibars atmospheric pressure.
What happens to engine power at higher temperatures or elevations?
At higher temperatures or elevations, the engine produces less power due to less dense air and compromised turbine cooling.
What must operators be careful about during ground testing?
Operators must be careful not to exceed temperature, RPM, or pressure limits during ground testing.
