What is N1, N2, EGT and EPR?
What is N1, N2, EGT and EPR?
N1= Low pressure compressor spool or fan rotation speed. Usually expressed as a % of Max N1.
N2= High pressure compressor rotation speed.
EGT= Exhaust gas temperature, indicates the temperature at the first stage of the turbine, which is the most critical temperature in the engine.
EPR= Engine pressure ratio of the inlet to the jet pipe, displayed on the EPR gauge to use as a parameter for setting engine thrust
What is the speed of sound at sea level according to ISA?
What is the speed of sound at sea level according to ISA?
662 kts
Local speed of sound = 39 x √(Temperature in Kelvin)
15°C in Kelvin is (15 + 273) = 288
So the local speed of sound = 39 x √288 = 662 kts
Some wings, flaps and rudders are indented, why?
Some wings, flaps and rudders are indented, why?
To increase the strength of the surfaces.
The same strategy is employed by plastic water bottles, by adding ridges to a surface you increase it's structural rigidity
What performance category was your last aircraft? How are airplanes classified?
What performance category was your last aircraft? How are airplanes classified?
Note: this question was asked to a candidate with previous Seneca experience, make sure to be able to answer this question for your previous aircraft type.
Seneca is class A.
Aircraft are classified according to their Vat.
Explain what coffin corner is and what happens when reaching the coffin corner?
Explain what coffin corner is and what happens when reaching the coffin corner?
Occurs at absolute ceiling where low speed buffet and high speed (Mach) buffet are coincident.
When reaching the coffin corner, both increasing and decreasing the corner speed will result in a loss of control (either the aircraft stalls, or mach buffeting starts).
While climbing with a SEP, in what temperature range can carb icing occur?
While climbing with a SEP, in what temperature range can carb icing occur?
Carb icing can occur with temperatures as high 30°C and humidity as low as 50%, but it is more likely when below 20°C and high humidity, especially during low power settings.
What is departure?
What is departure?
Departure is an east-west distance along a parallel line of latitude, other than the equator.
Departure is calculated by: Change of longitude(minutes) x cosine of latitude.
How does TCAS work?
How does TCAS work?
TCAS works by sending interrogations to other aircraft's transponders.
The transponder will reply to the interrogation in a similar way it responds to radar. From the time difference between the interrogation and the reply, the distance to the other aircraft is calculated. The reply itself contains the altitude of the other aircraft.
The distance and the altitude difference with the other aircraft is tracked to identify a trend which may result in a TA or eventually a RA.
What are the advantages of swept wings?
What are the advantages of swept wings?
Swept wings are:
Better for high speed flight as they have minimal camber and thickness reduce drag and delay Mcrit More stable in turbulence as they produce less lift and as a result they are less responsive to updraughts
What’s the temperature at FL150 according to ISA?
What’s the temperature at FL150 according to ISA?
-15°C
because:
-2°C per 1000 feet gives -30°C.
ISA: 15°C at sea level - 30°C = -15°C at FL150