Alittle help for ATP stuff

[35North]

A little help please:

1. What happens to EPR as speed increases?
2.What is convergency?
3.What is Gyroscopic precession and how does one calculate it?
4.What is density altitude and how does one calculate it?
5.Describe take off splay for straight and curved takeoffs
6.what tracking error does full scale deflection on an ILS represent?
7.what cloud types are associated with the passage of a cold or warm front?
8.Does a jet have a critical engine?
9.Define pressure altitude

Anyone?

[BigGrecian]

You should be able to look these answers up in your text books.
I would suggest posting on the JALS Forum (http://jals.co.uk/forum/) where you'll get some good answers.

(Although I could probably answer the questions - I'd have to confirm a thing or two first to ensure I wasn't giving duff gen - sorry!)

[Send Clowns]

I'm assuming you might not be on a course, as some of these fundamental and should have been emphasised, and so don't necessarily have access to course notes. If you do, look them up for more detailed answers. Otherwise, do you mind if I ask why you want to know?

2. Convergency is the angle between the meridians through two specified points.

3. Precession is the tendency of a force applied to one point of a spinning gyroscope to move the alignment of the axis in the same way as a force applied to a stationary gyro 90° further round, in the direction of rotation. You'd have to ask an instrument instructor about calculating it!

4. Density altitude is the altitude in ISA conditions with the same density as the air for which density altitude is to be calculated. Formula is

DA=PA+118.8xT

DA = Density altitude
PA = Pressure Altitude
T = Temperature deviation from ISA, +ve if warmer than ISA, -ve if colder

6. I believe it's 2½°

7. Warm - cirrus, altostratus, nimbostratus in that order
Cold - cumulus, altocumulus and (often embeddded) cumulonimbus

9. Pressure altitude is the altitude in ISA conditions with the same pressure as the air for which pressure altitude is to be calculated.

Send Clowns,
Gen Nav & Flt Plng, BCFT

[Alex Whittingham]

1. EPR Reduces with forward speed
5. What is take-off splay?
6. Depends on the instrument. Clowns is right for a mechanical 5 dot display, but it's 2º on a normal 2 dot EFIS ND and 1º on a 1 dot expanded scale on the EFIS PFD.
8. Generally, no.

[Flyrr100]

Are you serious?
Most of these are PPL questions!
I'm a US pilot (I know... third world license... I've heard them all before...) But these are all topics discussed in Private Pilot Training. Except maybe the EPR question. That's discussed in the US ATP training.

Things that make you go.... "mmmmmmm?"

Fly Safe.

[Send Clowns]

I disagree, FlyRR. I wouldn't have known much of this from my FAA PPL training, probably only the met question (and yes, I did fine in the exam and in the practice questions!), although 3, 4, 7 and 9 are covered by the JAA PPL syllabus. However several are fairly basic to the CPL and ATPL courses.

[Charlie Zulu]

If you're asking about calculating Gyro drift on a DI, here is how you calculate it.

Table for calculating drift in the northern hemisphere (reverse the signs for southern hemisphere):

Earth Rate - Minus
Latitude Nut - Plus
Transport Wander East - Minus
Transport Wader Wast - Plus

So if you have a DI with a Latitude Nut set for 40 Degrees North and you're flying at 240 knots groundspeed on a westerly heading at latitude 50N you would carry out the following.

Latitude Nut correction for 40N (a plus sign for the latitude nut set for the northern hemisphere):

+15 sin 40 = +9.64

Then you have the Earth Rate which is minus in the Northern Hemisphere:

-15 sin 50 = -11.49

Then for the transport wander, a plus sign for flying in a westerly direction in the northern hemisphere:

(Groundspeed / 60 * tan mean latitude that you're flying)

240 / 60 * tan 50 = +4.77 (plus because you are flying west)

Put them all together:

+9.64
-11.49
+4.77

= +2.92 degrees drift per hour (increasing in reading)

In JAA questions they sometimes give you a random drift error as well (giving a + or - as well) so you'd append that to the final answer. Be careful as sometimes they ask you what is the drift for part of an hour instead of a full hour... (I've been caught out in the feedback quesitons a couple of times).

Thus as you were flying 270 degrees (west) after an hour it would have drifted to 272.92 degrees.

Um I'm still doing my JAA ATPLs so I may be wrong... (hope not as I'm taking the exams soon and I'll be in major trouble if I get this wrong!).

By the way I don't think I would have known many of the answers to the question when I took my JAA PPL (CAA back in those days) seven to eight years ago.

Best wishes,

Charlie Zulu.

[low n' slow]

5 Describe the takeoff splay for straight and curved departures:

According to PANS-OPS a turning departure is one in which a turn is initiated wich alters the course by > 15 degrees.
The splay is a bit difficult to describe but I'll do my best. Best is to look at a picture (there's probably a good one in your airlaw book if you have one). The splay is in my underestanding the angle by which a specific area expands. On a VOR route for example, the splay increases, then decreases. All takeoff areas are measured from the departure end of runway (DER).
Splay for a straight departure is with no trackguidance: At DER 150 m to each side of centre line. This takes you into whats known as AREA 1 which extends 1.9 NM straight ahead. The angle by which the area expands is 15 degrees to each side measured from a parallel to the centreline. There is no AREA 2 designated for a non trackguidance departure.
Splay for a straight departure with trackguidance: AREA 1 is as before, but now there's an AREA 2. This starts after 1.9 NM from DER. Depending on if trackguidance is a VOR or NDB the area will decreas towards the aid by 7.8 or 10.3 degrees respectivly, measured from a parallel to the centreline. On passing the aid, the area will expand by the same figures. The area continues past the aid for another 2 NM if its a VOR and another 2.5 NM if it's an NDB.
For a turning departure AREA 1 is as before. AREA 2 will be affected by how great a course change the departure is designed with. Say that a turn of 30 degrees to the right is initiated some way into AREA 2. The left side splay will continue as in AREA 1 for a length depending on fix tolerance and flight technical tolerance, thereafter it will make a right 30 degree turn. On completion of this curve it increases by 15 degrees relative to a parallel to the new centreline. The fix and flight technical tolerance is basiacally a safety factor for ensuring the aircraft is overhead the turning fix and a safetyfactor to permit the aircraft to initiate the turn. The right splay will increase by 15 dergees measured from the new centreline until intersecting with the trackguidance splay which is as before: some form of fix on the centreline from which an obstacle clearance area is calculated. Splay is as before VOR 7.8 and NDB 10.3 degrees.
For an omnidirectional departure AREA 1 is as before. AREA 2 boudries will increase by 30 degrees relative to a parallel to the centreline.

I realise now that this explanation got a bit out of hand but I hope you were able to follow me. A summary:
The splay in AREA 1 is allways 15 degrees.
The splay in AREA 2 for a straight departure is - 7.8 VOR and -10.3 NDB. Past the fix the splay becomes positive.
The splay for a turning departure is nearly the same except for the fix and flight technical tolerance, after which the outside boundry turns by the same amount as the centreline and thereafter expands by 15 degrees outward until intersecting with the fix splay as in AREA 2 straight departure. Naturally, the splay is calculated to the sides of the trackguidance aid and not directly overhead. The width of this part I tend to forget and is not really relevant to your question.

regards/LnS