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HELP WITH TECHNICAL ISSUES

Published: Mar 02, 2003

I'm a screenwriter. Can you help me with some technical issues?



1.A group of thugs on the ground tracks a turboprop commuter plane using

a transponder-receiver system, which includes a dish, to identify the

frequency of the transponder on the plane. Is this possible?



2.The pilot flies at 178 degrees at 4100 feet. Is the altitude in this direction in odd

feet? And how is 4100 feet translated into aviation jargon?



3.The left engine is on fire. The pilot crabs to the right to

minimize fuselage exposure to the flames. Is this plausible?





Thanks.

Joshua

Khillman1@houston.rr.com

Comments (6) Post a comment

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ok,



Number one, no idea but probably not.



2: This is incorrect, when one flies a heading between 360 deg. and 179 deg. under VFR, you fly an odd altitude + 500ft.(i.e. 3500, 5500, 7500, etc...) between 180deg. and 359 deg. its even + 500 (i.e. 2500, 4500, 6500).



Under IFR it's the same but you don't add 500 ft.



3: if the left engine is one fire you would want to turn towards the left to shield the fuselage. turning to the right would expose the fuselage behind the wing. Anyway Aircraft fire spreads through fuel lines etc.. not by "jumping" from the wing to the fuselage so turning left wouldn't even do anything.



Hope this helps,



Isaac

Number one is plausable. They would probably use a TCAS unit for a GA aircraft, just on the ground. Same antennae as used on the aircraft (yes, a dish is more photogenic). The difficulty is that all transponders use the same frequencies. You would need to know the discreet transponder code to idnetify it. One other difficuly - TCAS units only identify proximity to traffic, not the individual flights. For something like that, you'd need access to the FAA ATC computers that have the translation from code to tail or flight number. If I were writing it, I would think it would be more dramatic to have a bad guy insider at a facility with a cell phone clandestinely telling the outside bad guys about the flight while watching a screen.



Number two - Altitudes are expressed in terms of height above mean sea level. If your flight is 4,100 feet above the ground, and the elevation at that point is 1,900 feet, then they would be at 6,000 feet, which is a legal IFR altitude for the direction of flight you've chosen. For the non-aviation audience, you'll have to stick in something about "they're at 6,000 - that's 41 hundred feet above us" or some such thing. Trouble with audiences and real world is that things get to messy. In "Die Hard" (or was it "Die Hard 2"?) there are procedures in place to keep airplanes and competent pilots from flying into the ground if an ILS is deliberately mis-aligned. And while I'm on a rant, because I work for a railroad as well as being a flight instructor, when Gene Wilder cut the locomotive off in "Silver Streak", the whole shebang would have had an emergency brake application and slid to a complete halt in about 1/2 to 3/4 mile, based on the speed and weight of the train as it appeared on screen. Not as cool as ramming a train depot, but there you have it.



Oh, BTW, altitudes are expressed as "4 thousand" or "5 thousand, 5 hundered" or, above 18,000 feet as "flight level one niner zero", etc.



Finally, left engine on fire? Kill the engine, feather the prop, kill the fuel supply (with full power to the right side), bank slightly into the right engine to kill the side slip which lowers overall drag so the plane can still maintain altitude (what you call crabbing is something else entirely - you crab into the wind to fly a straight path across the ground and the plane doesn't "know" it's crabbing). Finally, PUT THE AIRPLANE DOWN NOW WHILE THE WING IS STILL ATTACHED! A fire in the engine puts the wing spar on that side at serious risk. I'd rather land on a short runway and risk going off the end under control rather than have the wing break off and crash out of control.



Hope this helps.

Technical answers: #1: Not sure myself. Doubtful since the transponder replies to radar interrogation from the ground based transmitter/receiver. I doubt a hand-held or truck mounted unit could have sufficient energy to trigger a reply from the transponder. Why not just track the aircraft via internet tracking software, i.e. FlightAware or flight tracker. I'm not particularly fond that just anyone can track my aircraft while I'm in flight (especially my ex-wife), but if I've filed a flight plan with ATC, my flight progress is posted on public websites for anyone to monitor. #2: For visual flight rules the appropriate altitudes to fly are odd thousands plus 500 feet for Easterly magnetic courses (3,500 (above mean sea level), 5,500, etc.) Easterly magnetic courses are 0 degrees through 179 degrees. Note, Visual Flight Rules (VFR) only apply when the aircraft is in cruise flight higher than 3,000 feet above ground level, and VFR flgiht covers mostly recreational and small private aircraft activities) For instrument flight rules (what jet airliners fly under and many smaller private aircraft also fly under) the rules are the same, except omit the 500 feet (i.e. 0-179 would be odd thousands 1,000, 3,000, 5,000 etc.) while 180 to 359 degrees would be even thousands (2,000, 4,000, etc.). I used to teach my students to remember the rules by relating to how people from the east tend to be odd...but now I'm based on the east coast so I'll probably have to rethink that one. However, for instrument flight, air traffic control can assign appropriate altitudes to comply with terrain clearances and instrument navigation requirements. For example, during an instrument approach to a runway, it's not uncommon for an aircraft to be assigned an altitude such as 2,100 feet or 2,200 to start an approach. But you'll never hear an altitude assigned other than 100 foot increments (i.e. they'll never say maintain 2,150 feet). As for aviation jargon, VFR flight generally cannot be flown above 18,000 feet MSL. Above 18,000 feet, the aircraft must be on an instrument flight plan (IFR), and have received a clearance from air traffic control (ATC). From 18,000 feet MSL upward, the altitudes are referred to as "Flight Levels". ATC would clear an aircraft to "climb to and maintain flight level one niner zero, or FL two one zero). Below 18,000 feet examples would be "climb to and maintain seven thousand, five hundred (7,500), which, BTW, ATC doesn't generally control VFR traffic (i.e. altitude assignments) except in busy terminal areas. One other note...ATC pronounces the number 9 as "niner", and 3 as "tree", and 0 is zero. Whew...and I won't go into lowest usable flight levels or altimetry lessons. #3 Better to crab to the left (nose pointed left by applying left rudder and right aileron) to cause the flames to blow outboard from the left engine...away from the fuselage, and possibly the largest fuel tanks in the wings inboard of the engine nacelles (depending on the airplane's design). Anyway, hope it helps. BTW, I'm an airline pilot with flight instructor ratings, an aircraft mechanic, and a former writer for Jeppesen (leader in aviation training materials...or at least they were until I left...LOL)

[QUOTE=Shuckles;3010]Technical answers: #3 Better to crab to the left (nose pointed left by applying left rudder and right aileron) to cause the flames to blow outboard from the left engine...away from the fuselage, and possibly the largest fuel tanks in the wings inboard of the engine nacelles (depending on the airplane's design). Anyway, hope it helps. BTW, I'm an airline pilot with flight instructor ratings, an aircraft mechanic, and a former writer for Jeppesen (leader in aviation training materials...or at least they were until I left...LOL)[/QUOTE] Firstly, the OP's questions were asked over 6 years ago and are probably no longer relevent. Secondly, you [b]never[/b] crab [i]into[/i] a failing/failed engine. If it's on fire it's going to burn until extinguished regardless. With the experience that you claim to have, you should know better than that....

Item 1: Try calling someone in ATC; they might know. Or you could email Peter Garrison and ask him, he's really smart. You can find his contact info on his website: www.melmoth2.com. Even if you could track someone, you'd probably need more than their code to do any harm to an aircraft.

Item 2: It depends whether the aircraft is flying a true heading or magnetic heading. Magnetic heading is true heading plus or minus the magnetic variation, sometimes called declination. The variation , er, varies from about 22 degrees east on the west coast to about 20 degrees west on the east coast. The old rhyme I learned was: Variation east: magnetic least; Variation west; magnetic best.

The basic rule up here in Canada is that headings from 0 to 179 magnetic are flown at odd altitudes (3000, 5000 ... ) for IFR traffic and odd altitudes PLUS 500 feet for VFR traffics. On magnetic headings of 180 to 359 degrees IFRs use even altitudes and VFRs use even altitudes PLUS 500 feet.

You must distinguish between height above the ground —AGL— and height above mean sea level —MSL. Here in Canada we now describe altitudes below 18,000 feet MSL by stating the number of hundreds, so 4100 feet is "four 0ne hundred". This is because saying "forty-one hundred" can be confused with "fourteen hundred". Some pilots still prefer to say "four-thousand, one-hundred" or even use verbal shorthand like "four point one." I don't know the US standard but I suspect is is quite similar, since many many aircraft cross the Canada/US border each day. So using standardized language is a good idea. Altitudes above 17,999 feet are expressed as "Flight Levels", because everyone sets their altimeters to a standardized setting of 29.92 inches of mercury. A reading of 21,000 feet on the altimeter would be expressed as "Flight Level 210.

Item 3. Crabbing an aircraft to minimize exposure to fire won't do much except distract the pilot from what he/she really has to do: SURVIVE THE SITUATION!! Flames contacting the fuselage seems an overly dramatic concept. In a multi-engine aircraft the first action once a fire in an engine has been identified is to pull the fuel mixture control back to full lean position, and then immediately turn the fuel selector (aka gas tank selector) for that side of the aircraft to the off setting, to cut of fuel from that engine. The fuel lines will still have some positive fuel pressure in them, so it may take perhaps 10-20 seconds for that fuel to be drawn from the lines by the fuel pressure within. Then follow the engine-out checklist. If that does not extinguish the fire the next option is to dive the aircraft in an attempt to exhaust the flames by exposing it to too much oxygen to sustain burning. Another priority is to look for a place to land as soon as safely possible while broadcasting your situation and position to ATC. The old bromide is: Aviate, Navigate, Communicate.

Good luck with your screenplay, Joshua.

Nice information but really overkill! Josh doesn't want a flight lesson, he wants three simple answers. Remember, the audience is the non-flying public for the most part.

#1 It wouldn't matter if you did know the transponder code. The question is: what are you wanting to know about the flight plan in the first place? Tracking can be done by several means. It just looks more diabolical to have a radar dish so the audience is thrilled.

#2 If the aircraft is on an IFR flight plan: Odd thousandths feet. If the aircraft is following VFR flight rules: Odd thousandths plus 500 ft for the compass heading refered to in the question. Period. Neither Josh nor the viewing audience cares about MSL or AGL or all the minutiae given in the other responses. This aircraft is at 4,100 and needs to be higher or lower to be legal and safe. If there is a villian in the cockpit, I'm sure he doesn't care about ATC flight rules anyhow. In aircraft jargon: four thousand one hundred. Period.

#3 The left engine is on fire...let it burn! More dramatic for the audience. In reality there isn't enough information given to make a determination of which way to "crab". Don't know the type of aircraft, how big the fire is, etc.. In reality cut the fuel mixture to the affected engine and put the aircraft in a dive to extinguish the flames.

#4 And most important... IT'S ONLY A MOVIE! Not a flying lesson. Question: How do you know which guy in the room is a pilot? Answer: He'll tell you! Just for the record: yes I'm a licensed commercial pilot. Ha!

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