| Author | Message | ||
     Wolfridgerider |
Why does anyone have access to turn a transponder off on a plane these days? | ||
| Aesquire |
You turn it off when you park. There is a circuit breaker for it. There are multiple reasons to turn off a transponder. In no order....... It's a radio and uses power. If you leave it on it sucks the batteries dry. So it is on the master switch circuit The airport doesn't need to see parked planes and the data uses precious bandwidth. Maintenance. To isolate the transponder from the electrical system during voltage transients, like cranking the starters. Because you have to set it every time so there is no reason to leave it on. ( you get assigned a new code by ATC ) Answer your question?? | ||
| Aesquire |
In some planes you pull the fuse ( or trip the breaker ) on startup because the transponder is on the master switch. Seriously. Part of the checklist. Aircraft are weird that way. You're supposed to know what the switches do. And why. This tech.......computer tech box or toggle switch is built to be diagnosed and run with partial failures. It is not modern car technology built for zero mechanical skills. Most piston engine planes still have manual mixture control. Imagine that in a minivan. | ||
| B2tomtom |
The transponder is also set up so that it can be turned off during testing. Hours can be spent with avionics powered up and having a number of transmitters powered up on the ground that are not getting ready to fly would clutter the radar scopes. | ||
| Court |
>>>You're supposed to know what the switches do I'm a nerd. I used to spend an hour at a time . . . sitting in the cockpit, running normal and emergency procedures and practicing putting my fingers on certain breakers with my eyes closed. | ||
| Aesquire |
Now you can get a cockpit poster of the classic spam cans and put them next to your desk to help memorize the panel. ( spam cans referring to Cessna, Pipers, Mooneys, etc. ) Today's glass cockpit owners often bring a power supply to fire up the cockpit without starting the plane so they can practice running the computers. GPS, engine gauges, artificial horizon, even synthetic vision etc. give a modern pilot capacities undreamed of a few decades ago. But you have to figure out what the switches do, and when to push them, and now instead of a bank of toggles switches that run everything, you have a bank of toggle switches AND nested windows in nested menus in nested screens....... I was looking at instrument panel parts & gauges..... If you want to fly where the airlines go you need the right transponder. It's a whole separate radio set to install. Then there's a black box you can optionally install that queries your OWN transponder so you can be sure it works, and is set to the right codes. ( Air traffic Control gets very upset when they can't read your output, and you can actually get fines for using the wrong codes ) That's more complexity, and more weight. The good news is the radio companies now combine GPS & communication & navigation radios to cut down on the mass. The bad news is on a light aircraft mass is the enemy. So we figured..... doing the weight and balance calculations..... looking at a Sopwith Camel, to legally fly into Ohare, you have to add so much weight for the transponder you have to eliminate the pretty vintage gauges and go to a simple glass cockpit. This really ruins the vintage feel.........  | ||
| Court |
My KT76A weighed 3.1 pounds including the mounting tray and the KA60 antenna. | ||
| Wolfridgerider |
I understand running the batteries down and so on... it was a rhetorical question. I am just surprised, in the times we live in that they haven't installed some kind of fail safe. Turn the transponder off while in flight, emergency beacon turns on and you have a couple Squids or Jarheads hunting you down in a F18. Its hard for me to grasp a Boeing 777 can just vanish | ||
| Wolfridgerider |
and it also scares me a little..... now pat my head and tell me everything will be alright | ||
| Aesquire |
Nice. The Microair rig for the Camel is even lighter...... if you don't count harness & altitude encoder. The other bits made deleting the steam gauges and going modern the weight solution. The plane is still in planning stage. Not a petite pilot so a full scale Camel is the current choice. I want a Fokker DVIII but the workshop goes in first. ( actually it looks like I buy the engine first considering inflation on them. Rotec. ) | ||
| Aesquire |
Wolf.... the design philosophy is "be able to make it get you home and if that means turning off everything else....fine". When you build in security systems...... imagine that the plane won't let you fly it if the system reboots. "Stall warning. Altitude 10000. Please enter e mail address. Altitude 8000. Please enter password. Altitude 3000. Please re enter password. Altitude 1000. Please enter mothers maiden name. Altitu.............." | ||
| Wolfridgerider |
Have the ground crew duct tape one of these on the side of the plane. Not really... but you get the idea  | ||
| Aesquire |
Those things go in the thigh pocket. The radio gets Velcroed to the dashboard. Duct tape is structural.  | ||
| Ferris_von_bueller |
imagine that the plane won't let you fly it if the system reboots. Well, computers DO fly modern passenger aircraft. Fly-by-wire. Remember the Airbus A320 crash? (Message edited by ferris_von_bueller on March 15, 2014) | ||
| Just_ziptab |
"Flying airplanes is hard"... ....said Barbie doll never I guess 'seat of the pants' is gone with the Spirit of St. Louis/Charles Lindbergh.Probably only had a compass and a watch to get to Paris. | ||
| Aesquire |
Needle & ball. ( the other instruments Lindbergh had ) Some people still fly the old way. I flew for years before I had a working altimeter. After all, just look, there's the ground. Are things getting closer? you are going down. Now a vertical speed indicator? That's useful. So simple you can train a monkey to do it. You can train a chimp to drive a car. No problem. The trouble is they don't yield right of way, ever. No concept. Like driving in Mexico. | ||
| Just_ziptab |
The following emergency equipment was carried in the the Spirit of St. Louis on the flights between San Diego and Paris. 1 air raft, with pump and repair kit 1 canteen of water—4 quarts 1 Armbrust cup 5 cans of Army emergency rations 1 hunting knife 1 ball of cord 1 ball of string 1 large needle 1 flashlight 4 red flares, sealed in rubber tubes 1 match safe with matches 1 hack-saw blade | ||
| Aesquire |
http://www.dailymail.co.uk/news/article-2581817/Do omed-airliner-pilot-political-fanatic-Hours-taking -control-flight-MH370-attended-trial-jailed-opposi tion-leader-sodomite.html no opinion. | ||
| Sifo |
Only slightly related. My nephew is working on getting into commercial aviation right now. He took this shot of the Mackinaw Bridge yesterday.  | ||
| Oldog |
I have not flown in years, but flying a "spam can" in to Ohare or any major air port with the big iron is not some thing I would want to do, new post 911 rules not with standing, Yeah Court, you are not alone on that "nerd" thing, I started to do the instrument ticket and spent a lot of time on the ramp in the instructors plane with my eyes closed training to put my hands on switches and controls with eyes closed. | ||
| Sifo |
So I'm curious if Aesquire, or anyone else who has knowledge of this stuff, is what this guy is describing feasible? http://mh370shadow.com/post/79838944823/did-malays ian-airlines-370-disappear-using-sia68-sq68 | ||
| Hootowl |
Interesting. But military radar is pretty sophisticated, and even search radar (vs. track or targeting radar) could likely distinguish between two aircraft of that size, even if they were flying very close together. Depending on the range of the radar of course. Longer range = longer pulse width = lower target resolution. And also longer minimum range, but that's not really important here. | ||
| Xdigitalx |
Dumb question... are these way points we all hear folks referring to designating where they wanted the plane to go...,(the plot/plan of the route) OR is it where it actually has been/flown?? I mean just cuz there is a way point doesn't mean it flew there right? (I worked at a little airport for a summer back in the 80's so don't beat me up too bad. flew a couple training flights... painted some runway lines.. that's it. lol) | ||
| Airbozo |
This is the best prediction of what may have happened that I have heard of. Yes, during an electrical fire, the first thing you do is start pulling busses... http://www.wired.com/autopia/2014/03/mh370-electri cal-fire/ | ||
| Hootowl |
That is the best explanation I've heard yet. | ||
| Sifo |
+1 on Airbozo's link. That does make a lot of sense. One thing I question about it though, I was lead to believe (by news media  ) that the pings from the engines contained altitude data. It makes sense to me that they would too, if they are meant to track how the engines are performing. That writer said that altitude data came from radar tracking, which could be influenced by numerous factors. It's beyond my scope of knowledge. I would think communicating their situation would be fairly high on their priority list. Even given that immediate survival is tops on the list, if they survived long enough for maneuvers like climbing to 45,000 feet, they would likely have had a moment to let controllers know that they were having serious problems. Then again, parts of their communications equipment may have been burning. Interesting. But military radar is pretty sophisticated, and even search radar (vs. track or targeting radar) could likely distinguish between two aircraft of that size, even if they were flying very close together. I would have thought so too. I do wonder if they could be close enough to go unnoticed though, especially with only a single bit of transponder data showing up on the controllers radar. Reminds me of a certain movie about a sub commander with a tattoo on his dick. | ||
| Hughlysses |
They were discussing the possibility of the aircraft hiding in the shadow of a passing flight last night on CNN. Their experts said it was possible, but that the collision avoidance radar on the "shadowed" plane would have picked it up and they would have reported it, so they thought it extremely unlikely that this is a possibility. The electrical fire theory sounds pretty plausible except that the fire would have had to occurred in a very tight time window, after the co-pilot signed off but before they would have contacted Viet Namese ATC. The fire would also have had to kill the pilot and co-pilot, but not damage the plane badly enough so that it couldn't keep flying on its own for several more hours. (Message edited by Hughlysses on March 18, 2014) | ||
| Sifo |
I was wondering about the collision avoidance systems too. I wasn't sure if they used active radar on their own plane, or just used transponder data. I don't think that 360 degree radar coverage is all that easy on a typical commercial jet. It would be interesting to hear from those who know the systems. | ||
| Reindog |
Occam's Razor says this theory is the most plausible explanation. | ||
| Aesquire |
First. Experts can be wrong. Often are. The kind that goes on tv to get his 15 minutes of fame are never the ones you really want to ask questions of. Waypoints. they are places in space/on the ground in the GPS or on a map. There are waypoints planned all the way to the destination. Has nothing to do with where the airplane really is, unless it's a waypoint you punch into your GPS ("I am here") or make a mark on your map. An Airliner has it's flight planned long before it takes off, and alternate routes ready in case of storm or other problems. As to radar on the "shadowed" plane picking up a plane "hiding" behind it? Doubtful. The traffic information is from transponders, all these planes transmit "Hi! It's Me" radio signals in reply when another plane transmits. ( that's why they are called trans-(mitting)-(re)-sponders.) An airliner won't carry radar that looks in all directions that is designed to pick up other airplanes. Airforce One might, an AWACS does, but even fighter planes only "look" forward. They "listen" in all directions for radar, especially backwards. ( as an aside, WW2 fighters sometimes carried a tiny ( by the day's standards ) radar set in the tail to warn of an enemy coming up from behind. A light would flash & buzzer would sound. No "screen". Some guys were saved by this, but a lot would turn it off since their own buddies in formation would set it off. ) As to military ground based & AWACS type air based radar spotting a plane trying to "hide behind" another? maybe. If they were looking for it. With the right gear. and recorded it. All that stuff tends to be recorded today for future review and training purposes, but it's not a universal thing. I have no Idea if the locals record radar tracks. What you see is dots or computer simulations with information overlays... on dots. Or smears. I haven't been in a tower to watch ATC for over 13 years. I'm seriously impressed with ATC almost all the time. Not an easy job. The most hilarious version of that is "Oshkosh" the Airventure EAA meet which becomes the busiest airport in the world each year. It's so busy they sell cd's of the tower patter. Like an Auction for landing. |
