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azax 22nd Feb 2011 04:49

JET EXAM - Study Portal ONLY
 
Please do no post queries about your reference no.
or examination centers. :=

Let this be a thread to share only exam oriented knowledge.

Thank you.

P.S.

indian airways limit
46,000' / 49,000' ???

v1_rotate 22nd Feb 2011 07:02

FlightLevel 460

cvchetan 22nd Feb 2011 14:59

Tech is basic of a/c structure, controls, Engines including jet engines, Basics of different systems etc.

For Nav they'll ask from everything including CP/PNR. Then numericals will be of very simple numbers and will be there to judge if your concept is right.

Radio aids will focus on workings, errors etc of various devices and again numericals will be very basic in nature.

harsh786techy 22nd Feb 2011 15:45

Ques-what is the requiremnets for
1. CAVOK
2. SKC

I think cavok is 10 km vis and no clouds base below 5000 and no TS FG etc.
But can someone put some light on SKC

azax 22nd Feb 2011 23:02

they will try to cover most subjects in a variety of questions...
brushing up everything you have learned is the way to go.
cp pnr is one of the key concepts of flying ... which cannot be not-asked in selection examinations.

anyway

SKC is sky clear ... no clouds
is used to indicate the cloud amount
amongst sct bkn ovc
or
sky conditions
amongst cb tcu clr-sky clear below 12000' AGL i.e. because when u speak of clouds its always above ground level.

CAVOK
is ceiling and visibility ok
which indicates VIS is 10k+ with no shallow fog
usage mostly vfr
no cloud below 5000' or lowest safe which ever is higher

CAVU
is c & V unlimited
same thing but no clds below 10000'
usage mostly ifr

Uniform. 23rd Feb 2011 08:02

Does the radio nav includes the basic equipment like NDB/ADF, VOR, ILS, MLS, DME, TCAS etc :E

or we have to study others like INS, IRS, GPWS, EFIS, FLIGHT warning also???? :sad:

harsh786techy 23rd Feb 2011 08:13

@azax
 
ok, so if conditions are
8km+ Vis and NO CLOUDS what would be mentioned in METAR?

Is it still going to CAVOK or SKC

azax 23rd Feb 2011 08:25

its an indian airline recruiting -
so i think they might require indian pilots to know nav topics that
the dgca expects us to know...
so i am guessing yes questions on all nav and radio aids could be asked

but certainly not IRS and |INS


and as for the forecast

VIS 8K
or 8000
SKC

both will be mentioned

alpha_victor_romeo 23rd Feb 2011 08:43

stall speed at 8000ft 45kts...
stall speed at 20000ft ???

alpha_victor_romeo 23rd Feb 2011 08:46

Guys which books are you referring for the study of tech ??

plz tell me asap

t.a 23rd Feb 2011 09:11

stall depends on angle of attack and not on airspeed. so will stall at the same IAS at any given altitude.

DJ Flyboy 23rd Feb 2011 12:39

What is the primary role of the turbine in
Turboprop
Turbofan

flyinghigh89 23rd Feb 2011 13:17

There is a question in the other thread which is raising alot of confusion..I would like to ask it here-

Will an aircraft descend faster in headwind/tailwind?

shanx 23rd Feb 2011 13:44


stall speed at 8000ft 45kts...
stall speed at 20000ft ???
An airplane can stall at ANY speed at ANY altitude.

As long as Angle of Attack is exceeded, the airplane will stall.

The question doesn't make sense unless of course it has been taken from some DGCA "question bank".

Sierra2467 23rd Feb 2011 13:48

where does the stall on a wing occur first? wing tip/wing root?
does it differ for swept wing/washout wing?
thnx in advance

v1_rotate 23rd Feb 2011 13:49

Yup.

The Indicated Stall Speed would always remain the same , its just that the TAS would be higher at higher altitudes.

How to put an exact figure to it based on the data given i do not know. :confused:

cvchetan 23rd Feb 2011 13:52

wing roots are the first to stall.. that is because in case of a stall, the ailerons which are at the wing ends will still be functional..

shanx 23rd Feb 2011 13:55


There is a question in the other thread which is raising alot of confusion..I would like to ask it here-

Will an aircraft descend faster in headwind/tailwind?
As far as RATE OF DESCENT is concerned, winds have no effect.

(If that is what you're trying to mean by asking which aircraft will "descend faster").

shanx 23rd Feb 2011 13:57


The Indicated Stall Speed would always remain the same , its just that the TAS would be higher at higher altitudes.
Not really.

The airplane can be made to stall at various indicated airspeeds.

v1_rotate 23rd Feb 2011 13:57

@ Sierra2467
 
Ideally we would want the wing root to stall first, so we still have aileron effectiveness to help in a stabilized recovery.

In swept back wings , unfortunately there is a tendency for the wing tip to stall first due to span-wise flow. One solution considered was using forward swept wings, but this causes excessive 'wingtwist'

Stall strips, Washout etc are used to ensure that the airfoil would stall first at the wingroot

v1_rotate 23rd Feb 2011 14:00

@shanx
 
Yes true and correct, sorry about that.

The Stall speed (IAS) does increase times the square root of the load factor.

Sierra2467 23rd Feb 2011 14:02

@cvchetan v1_rotate
Ok, so incase they ask- a wing stalls at the root first,unless "swept wing" is specified in which case the wing stalls at the tip first, right?
thnx again :)

shanx 23rd Feb 2011 14:04

@v1 rotate

Yes. Was just going to add ...

Stall speed depends on load factor.

So as an example, an aircraft that normally stalls at 70 KIAS, can be made to stall at 90 or 100 Kts (Indicated) by forcefully yanking back the controls.

(in other words, inducing more Gs hence .. increasing load factor)

v1_rotate 23rd Feb 2011 14:12

@Sierra2467

Yes, although I dont think they would ask the question that bluntly, because its still rather ambiguous. The planform is also a factor, The stall characteristics of an elliptical wing for example are not as favorable as a rectangular wing.

And also this unfavorable tendency on swept back wings can be minimized with Washout, stall strips , wing fences etc...

SuperflyTNT 23rd Feb 2011 18:22

Doubt.
 
When in ground effect - Lift increases and Induced drag decreases. So, when out of ground effect, Lift decreases and Induced drag inc. ? Is that right?

Sierra2467 24th Feb 2011 09:08

are you guys doing the questions from oxford series? those who appeared last time said that oxfords level is too high for jet exam?!
any suggestions plz?

t.a 24th Feb 2011 10:47

@flyinghigh89
I am not sure if my thinking towards this answer is appropriate or not.
But would like to recall that, on an ILS if there is a change in wind direction which if resulted in change in Ground speed, then to remain on the glide slope, then if Gs decreases then ROD decreases and if Increases then ROD Increases.(which is derived from the formula angle*100*Gs/60)

so applying this principle to your Question, when an aircraft is descending in a still air and later observed a wind change, then if we apply the vice-versa of the above (since u are not giving a correction in this scenario) and the above law is to stay on the Glide slope.

So the resultant would be that, on a Head wind (Gs Decreases ) so the rate of descent increases.

Please correct me, if u find a mistake.

Thanks.

djajay.jayaraj 24th Feb 2011 11:54

In the last Jet Exam, Was there Any Questions Bases on Mass & Acceleration, If so anyone remember what it was ?

I remember seeing it somewhere on the Jet Air-Thread, But unable to Find it now..

AJ

alpha_victor_romeo 24th Feb 2011 12:25

Info
 
I still didn't get the answer ??:confused:

Does Stall Speed change with height..??

BTW This is a question was asked to me by my friend who appeared Indigo exam last time and recollected this question..:ok:

So if you guys could help...

Also Shape of Earth : Ellipsoid or oblate spheroid..??:confused:

Wat is TVMDC type ques..??

What is geomertic Pitch..??

any idea bout Magnus Effect..??

Wat are ACW Generators..??

These are ques frm INDIGO exam first session.. Kindly post any info you might have on any of the above topics.....:ok:

tmbpilot 24th Feb 2011 13:36

@alpha_victor_romeo-----stall speed increases with alt....description is quite theoretical ,from what i remember is it falls a little as we climb and then starts to increase and becomes more than the original stall speed....correct me if im wrong


shape of the earth strictly speaking its an oblate spheriod

geometric pitch of a prop is the horizontal distance a free propellor will cover in one rotation....effective is the actual distance and the diff between them is slip...


what an unnecessary question:ugh: but magnus effect takes place when when an object is rotating it causes an whirlpool around it ...quite like shaktimaan used to do:cool:

ACW or AC wild type generators have an changing frequency ...as this generator speeds up or slows down freq changes..

@DJ Flyboy
in an turboprop ac turbine is used to drive the prop ,,in an turbojet its used to drive an compressor

correct me if im wrong anywhr

planeboy_777 24th Feb 2011 14:04


@alpha_victor_romeo-----stall speed increases with alt....description is quite theoretical ,from what i remember is it falls a little as we climb and then starts to increase and becomes more than the original stall speed....correct me if im wrong

thats incorrect my friend........ Stall is dependent on the Dynamic pressure....which is IAS (.5x[row]x [TAS]x[TAS]) ..

the green arc in your ASI never changes if you ever notice:pp

:ok::ok::ok::ok::ok::ok::ok:

alpha_victor_romeo 24th Feb 2011 14:05

Thnx
 
@ above Thank you for your response.... if you dnt mind me asking

could you please refer me the books you study from... you seem to have a good understanding of the subject...

alpha_victor_romeo 24th Feb 2011 14:09

guys i still need some formula if u claim .... it will change with altitude pls tell me the value how much if 45 kts at 8000ft 20 000 ft how much..??

planeboy_777 24th Feb 2011 14:46

The Formula is Lift = .5 x [Density] x TAS x TAS x S x Cl(co-efficient of lift)



Stall will occsur just after when Cl reaches its Max so itzz constant for a wing...the only variable is Density and TAS

at high altitudes Density Decreases and TAS is increased automatically increased so the dynamic pressure aka IAS aka .5 x [Density] x [TAS] x [TAS] remains contant

tmbpilot 24th Feb 2011 15:27

@planeboy_777 at lower range of altitude stall speed does not vary with alt,this is because at these low altitudes the mach number is less than 0.4 m too low for compressibility to be present.at 30000ft the mach number has increased to such an extent the rise in stall speed becomes apparent.......so rephrasing my reply"as alt inc,stall speed is initially constant then increases due to compressibility".......if u have an oxford book refer pg 7-35......

cyrilroy21 24th Feb 2011 17:22

@tmbpilot

Are referring to IAS or TAS when it comes to stall speed ?

Pulkdahulk 24th Feb 2011 19:04

Stall speed IAS remains the same at all altitudes.

Please refer

http://www.pprune.org/tech-log/10859...ude-stall.html

SuperflyTNT 24th Feb 2011 20:56

Can anyone share the METAR and TAF minimums over here? Thanks.

shanx 24th Feb 2011 21:15

@Pulkdahulk


Stall speed IAS remains the same at all altitudes.
Incorrect.

You can stall the airplane at a much higher IAS by inducing more G's.

Which is why an airplane would stall at a higher IAS, when in a really steep turn, or if the yoke is yanked back real hard.

neels0908 25th Feb 2011 02:47

stall speed
 
guys....
with regard to the question on stall speed,

the formula for lift is : LIFT= (C.L) * {(0.5) * (rho) * (TAS) * (TAS)}
where {(0.5) * (rho) * (TAS) * (TAS)} is the dynamic pressure, which gives the indicated airspeed.

So, from the above equation, when we equate for {(0.5) * (rho) * (TAS) * (TAS)} , it will be : (dynamic pressure) = LIFT/(C.L)

and stall occurs when the coefficient of lift is maximum.
Hence, during stall, (dynamic pressure) =LIFT / (C.L max)

and since C.L max is constant for an aerofoil and the load factor is directly proportional to the Lift produced during straight and level flight, if the load factor acting on an A/c is the same, it will always stall at the same IAS.

Also, when (C.L) = (C.L max) , that is the AoA at which the A/c will always stall irrespective of the Altitude or the speed. { Please note that whenever most of the books say speed, they mean the TAS (v) }

Now , from the very first equation , if we equate for the speed {i.e TAS (v)}, we get

(TAS) * (TAS) {or (v squared)} = [ LIFT / { (C.L max) * (0.5) * (rho) }]


hence TAS {or (v)} will be equal to the square root of the expression on the right hand side of the above equation.

From the derived equations for the TAS {or (v)} and the IAS , we see that density (rho) is involved only in the equation,

So.... Under constant load factor, the IAS at which an A/c will stall will always remain constant, but the TAS will vary inversely with density

i.e , the A/c will stall at a higher TAS at higher altitudes, since density is lower.


Hope this helps .
Best o Luck to all u guys.... :ok:


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