Strat

Hello, I am new here. Please to have found out a great site like this. I am a student pilot and many more things are still in mystery for me hehe. So,I got certain questions which have long been in doubt for me. please kindly advise.

1. What an ATC advisory such as "traffic 10 o'clock, 2 miles...." is based on the position of that of that traffic relative to the plane's magnetic heading or actual ground track?

2. What kind of speed is based on the minimum climb gradient for SID?

3. The published MSA for each sector provides magnetic or true heading?

4. According to no.3, in what situation the true or magnetic are used? in my understanding, true is used in the map things, am I right?

5. Why the predicted wind direction in the METAR or ATC reporting is in TRUE direction? wouldn't it easier for pilots if it is given in MAGNETIC?

6. What is ESAD? and what is its usage?

I hope these ain't too many questions for you. Many great experienced pilots here. I hope you could please kindly advise me. I would appreciate.

FlyerJosh

1) Traffic advisories are based on ground track (IE what the controller sees over the radar scope)

2) Climb gradients aren't based on speed per se, but on angles. These angles are converted to feet rise per nautical mile, which then can be converted to feet per minute climb depending on whatever groundspeed the aircraft is travelling at. The faster the airplane, the greater the climb rate must be to maintain the same angle climb. IIRC, standard instrument departure gradients are based on obstacle clearance of a climb of about 150' per NM up to the minimum IFR altitude.

3) Dunno. Can't remember and can't find the answer. I want to say magnetic though.

4) Maps are in true headings (based on lat/long). Magnetic north actually moves around slowly, depending on several factors that affect the magnetic lines of the earth. I imagine that it is much easier to adjust magnetic correction lines on a map then to adjust the entire map for these changes?

5) I have no clue why Metars and TAF's are true. Just the way it is... IIRC, tower observations are given in magnetic? Can't remember. Perhaps somebody else knows...

6) ESAD? in what context is it used? Right off I have no clue what it is.

Strat

I really appreciate sir for answering to my questions. Is anyone else having the answers for the rest. please kindly advise.

Ps. ESAD is used in the computer flight plan and I have no idea what is it used for?

rickair7777

MSA's are referenced magnetic, since they are based on NAVAIDS which are also referenced magnetic. The only things I can think of in aviation that are true are chart alignment and most weather products, including winds aloft (ATIS winds are magnetic). True is normally only used in flight planning to account for winds aloft, and then is converted to magnetic for operational use.

ATIS winds are magnetic because they are recorded by ATC personnel for pilot use only, and runways are magnetic, so you want to know the wind relative to the runway in use. Other weather info products are generated by the national weather service for general, scientific, and aviation use, so they use true. METAR and TAF are used for general info by pilots, so the exact wind direction is not critical. Winds aloft, when used for flight planning purposes, must be accounted for correctly....so you take your true course, apply true wind to get a true heading, then apply variation (and deviation) to get a magnetic heading to fly.

Note: ASOS measures true wind, and transmits this to the NWS for production of METARs. ASOS converts true to magnetic for the radio transmission that pilors receive.

Strat

That 's the TRUE knowledge! Thanks!!
Anyone else for the rest,please?

rickair7777

Never heard of ESAD...what is the context?

Do you mean ADS-B by any chance?

Strat

ESAD stands for Equivalent/Estimated Still Air Distance. it is used in a computer flight plan for the disregard of enroute wind aloft or something, I am not certain,Rickair7777. it's some kinda useful information for fuel calculation but don't know what is its actual and detailed meaning.

rightseater

from what i remember when i was working on my dispatch stuff ESAD was basically just a nifty program to figure out how far we could go with one engine inoperative in still air...basically used for determining how far away are takeoff alternate could be, and how much fuel we would use getting there...

Strat

Hey... thanks a lot Rightseater. So Is it useful when inflight, right?
does it have something to do with groundspeed or airspeed? please advise more

FlyerJosh

Strat,

My FMS has ESAD on it... to be perfectly honest I have absolutely no practical use for it while in flight... (the Citation has ESAD info on it... the CRJ does not).

If anybody knows of any good uses, I'm all ears!