An knowledgeable commercial plane experts on here?

[Jroc]

In light of Malaysia Airlines MH370 getting lost somethings been kind of on my mind.

How come I could go murder someone, leave the scene, and then my phone signal can be looked at and place me at the scene of the crime at the before time when they think it took place, but they can let a 300+ million dollar Triple 7(one of the most bad ass modern day airliners there is) get lost and they don't have a clue to where it's at?

That is just straight up ridiculous. This is 2014 and we can let one of the most advanced commercial planes get lost? There should be something in all modern airlines that says its plane in at this position at 12:00, its at this position at 1:00, it's at this position at 1:02, it's at this position at 1:02.1, and this position at 1:02.2, etc, etc.

While the transponder might do this what business do the pilots have of even being able to cut it off? This isn't a B-52. Unless you're a terrorist you're not looking to go bomb a city or anything so what do you need to be in stealth mode for? A airline pilot flying passengers is at work. Unless you're is in the restroom you are not entitled to privacy. From passengers yes, pilots are entitled to privacy from them as they are flying a airplane, and are responsible for a lot of lives, and that could be dangerous, but certainly not from the ground knowing what the plane is doing. Did we not learn anything from 9/11? Turning the transponders off is exactly what the terrorist did, and it made them hard to track, and we lost the planes position, which happened again with flight MH370. There should be no option to turn the device that communicates what the plane is doing to the ground off. This plane is a post 9/11 built aircraft.

I know this is kind of a rant, but this kind of pisses me off a little as it's stupid. I mean you tighten up on security at airports, and this and that but you keep the ability to make the plane hard to track an option to turn off. Again 9/11 proved that doing so greatly benefited the terrorist. We should of learned from that. For example from my understanding after D.B. Cooper they made the Airstairs on the 727 where they wouldn't open when the landing gear is retracted.

IDK what do y'all think? Maybe there is an airline pilot on here who can shed some light on as to why they are given the option to hide a privately own plane with hundreds of people on it from the ground? This just seems really pathetic and lousy that this plane got lost and then flew for 6-8 hours afterwards, and they still really don't know where the hell it's at several weeks later.

 

[James Snover]

A pilot (and crew) have to have the ability to disable any circuit at any time if that circuit is causing a fire, or appears capable of causing harm to the aircraft. Likewise, all those circuits are susceptible to fire: burn through the wires, no more transponder signal. So there's two ways it could have happened. Especially if the transponder is what caused the fire. A transponder puts out some wattage, it doesn't run off a pair of AA's.

I work on electronics/electrical equipment, I fix medical x-ray machines. It doesn't matter how thoroughly you design your circuit, how redundant you make it, how much "graceful degradation*" you design into it. Sometimes they just blow sparks.

*Graceful degradation: you design a circuit in such a way that when it fails, the whole thing doesn't die at once. You begin to lose capacity, if it could transmit at 100 watts, now you can only put out 85 watts, it doesn't just blow a breaker and shut the whole thing down. And sometimes that goes wrong, too, and the whole thing pops a breaker and shuts down or catches on fire.

In light of Malaysia Airlines MH370 getting lost somethings been kind of on my mind.

How come I could go murder someone, leave the scene, and then my phone signal can be looked at and place me at the scene of the crime at the before time when they think it took place, but they can let a 300+ million dollar Triple 7(one of the most bad ass modern day airliners there is) get lost and they don't have a clue to where it's at?

That is just straight up ridiculous. This is 2014 and we can let one of the most advanced commercial planes get lost? There should be something in all modern airlines that says its plane in at this position at 12:00, its at this position at 1:00, it's at this position at 1:02, it's at this position at 1:02.1, and this position at 1:02.2, etc, etc.

While the transponder might do this what business do the pilots have of even being able to cut it off? This isn't a B-52. Unless you're a terrorist you're not looking to go bomb a city or anything so what do you need to be in stealth mode for? A airline pilot flying passengers is at work. Unless you're is in the restroom you are not entitled to privacy. From passengers yes, pilots are entitled to privacy from them as they are flying a airplane, and are responsible for a lot of lives, and that could be dangerous, but certainly not from the ground knowing what the plane is doing. Did we not learn anything from 9/11? Turning the transponders off is exactly what the terrorist did, and it made them hard to track, and we lost the planes position, which happened again with flight MH370. There should be no option to turn the device that communicates what the plane is doing to the ground off. This plane is a post 9/11 built aircraft.

I know this is kind of a rant, but this kind of pisses me off a little as it's stupid. I mean you tighten up on security at airports, and this and that but you keep the ability to make the plane hard to track an option to turn off. Again 9/11 proved that doing so greatly benefited the terrorist. We should of learned from that. For example from my understanding after D.B. Cooper they made the Airstairs on the 727 where they wouldn't open when the landing gear is retracted.

IDK what do y'all think? Maybe there is an airline pilot on here who can shed some light on as to why they are given the option to hide a privately own plane with hundreds of people on it from the ground? This just seems really pathetic and lousy that this plane got lost and then flew for 6-8 hours afterwards, and they still really don't know where the hell it's at several weeks later.

 

[Silverstrike]

Having the option of turning the transponder like you said off was for a few reasons

Being hijacked and so telling ground control without doing it by radio or vocal means.

Or if there was a power problem and so turning it off and so bringing the volts back up to a safe operating level ie* like 6 volts and turn it off and be up to 12 volts or what ever a regular jetliner has for an electrical system readout.

But I agree on one thing that the transponder needs to be on it's own power source through an APU (Aux. Power Unit) totally independent from the aircraft systems itself. Keep the switch in the cockpits but never tell the pilots about it. That way it runs no matter what and no one would be the wiser of it.

 

[jimmy77]

As Mr. Snover stated correctly, the pilot needs the ability to shut down circuits in case of fire. The one thing they could do is use an elecromagnetic field type charge so there's no direct circuit to the Transponder. If there's a problem they can shut down the charging circuit but, the charged batteries will still run the transponder. I would also put those batteries/transponder in a fireproof container just in case.

 

[focussvtracer]

Turning off the beacon radar wouldn't make the airplane disappear. The primary radar will still pick up the aircraft. Radar's have a max range of about 250 miles.
I am not familiar with how they control traffic over there. In the USA we record radar data and can play it back at anytime. If they had enroute air traffic control system like we have in the USA it would be very obvious they were off course.

 

[GT_Jim]

These pilots aren't the guys making 20 grand a year at the regionals. These are professional pilots paid the big bucks because they know (or are supposed to know) what they are doing. If they determine a system needs shut down in flight they absolutely need the ability to do so.

Safety of flight is the number one priority for any air crew and nothing man made is perfect.

Next up, this was not a U.S. airline and flies under different rules compared to U.S. carriers.

It's up to the airlines on what kind of data transmission services they have. Something people seem to keep ignoring is that Malaysian airlines already had money issues.

Some basic ACARS info;

• ACARS is an automated aircraft communication system that transmits a/c information, including navigation, operations, maintenance, etc to ATC and maintenance facilities.
• ACARS is not a flight system - it is not needed for safe flight.
• ACARS is a subscription service and costs money. All indications are the MH370 was subscribed only to engine health monitoring and data from that is sent to Rolls Royce.
• This last fact (only EHM) is somewhat curious because of 3/18 reports of new way-points being programmed. This would require ADS-C (see ADS-C information below)
• ACARS communicates via VHF, HF or SATCOM. The communications channel depends on availability and is independent of the ACARS.
• ACARS can be instructed not to use SATCOM, HF or VHF from the Cockpit. This would effectively stop ACARS from sending data. Access to the EE bay is not required.

• SATCOM is a communications channel - Satellite Communications. It is a radio system that uses satellites to communicate various information.
• SATCOM is not ACARS - it is one of the channels ACARS can use.
• The Inmarsat Senior VP likened the Inmarsat box on MH370 to a 'handset' and the Satellites to the network. ACARS, Texting, etc are all "applications" that run on the 'handset'
• The system pings the aircraft roughly hourly.
• The SATCOM system on MH370 is a "Classic Aero" set and connects to Inmarsat 3 satellites. In the area covered, the only satellite with coverage is IOR. (Source Inmarsat)

ADS-C information;
• ADS-C stands for Aircraft Dependent Surveillance - Contract.
• The "Dependent" is because it "depends" on the aircraft taking action - as opposed to "independent" like radar.
• Contract means there must be a "contract" or "agreement" set up by the controllers an/or crew to send information.
• ADS-C is not required to be used.
• ADS-C can be programed to report periodically, on demand, on event. It can be initiated by the crew in an emergency.
• Various data groups can be sent. The one relevant to this discussion is the Predicted Route Group which includes ETA, altitude, lat/long at next way-point and next+1 way-point.
• The only way we know of for this information to be available to authorities is if the ACAR's report at 1:07 included the "Predicted Route Group."
• ADS-C is transmitted via ACARS which can use SATCOM, VHF or HF.
• ADS-C does not transmit via transponder.

http://prezi.com/pcuvxhcklsda/ads-c-overview/

Please note however that turning ACARS "off" in the cockpit doesn't disable the actual transmitter, this is why there are "pings" after the system was "disabled". Each aircraft has a unique satellite ID code and the system "handshakes" at regular intervals unless something catastrophic happens.

There is a circuit breaker in the EE (Electronic and Equipment) bay however which can be accessed by ground MX personal and the flight crew if they are really motivated. I highly doubt any terrorist could find the breaker or even know it exist though. No sane person goes to the EE bay during flight unless it's critical.