Why Can Pilots Still Turn Off Their Transponders?

[Johnboy60]

We might know what happened to Malaysia Airlines Flight 370 were it not for one thing: The aircraft's transponder was somehow turned off. In the New York Times, Gregg Easterbrook notes that the 9/11 hijackers were also quick to turn the transponders off, which is what caused air traffic controllers to lose time trying to locate the planes. After that tragedy, Easterbrook "would have bet my life’s savings that the transponder, which broadcasts an aircraft’s location and identity, would be re-engineered to prevent hijackers from turning such units off," he writes. "But nothing was done."

Why Can Pilots Still Turn Off Their Transponders? - There's no reason for it, and it's time for a change: Gregg Easterbrook

 

[Billnew]

I see no reason why there is the ability to turn it on and off inside the plane.
It should only be reached outside the plane to be worked on.

 

[cow451]

I see no reason why there is the ability to turn it on and off inside the plane.
It should only be reached outside the plane to be worked on.

 

[bhsmte]

Right now, they need to turn it off when they land, so the plane does not show up on ground controls radar when they are taxing and clutter up radar and make their job more difficult. Also, if there is a problem in flight, electrical problem/fire etc., they need to be able to turn off devices to control the issue.

What they should have on these planes, is a separate device, not used by traffic control, that can be engaged when necessary, to track these planes.

 

[keith99]

Right now, they need to turn it off when they land, so the plane does not show up on ground controls radar when they are taxing and clutter up radar and make their job more difficult. Also, if there is a problem in flight, electrical problem/fire etc., they need to be able to turn off devices to control the issue.

What they should have on these planes, is a separate device, not used by traffic control, that can be engaged when necessary, to track these planes.

My father was a IFR rated pilot. I vaguely recall him turning the transponder on after takeoff. An echo of what you just said.

 

[Water Cross]

What they should have on these planes, is a separate device, not used by traffic control, that can be engaged when necessary, to track these planes.

I think after this Malaysian flight problem that will be something that is introduced in future.
The plane communications can be cut off simply by pulling a breaker. There is another device in the plane that can only be disengaged on purpose. Something to do with communications, it's an acronym that I can't think of now, but that was apparently disengaged as well.
As it stands the behavior of this plane and the loss of all ability to track or communicate with it, or the passengers through their cell phones, seems to indicate an inside job. A deliberate action in taking this plane and its passengers.

Now the question remains, why?

 

[bhsmte]

My father was a IFR rated pilot. I vaguely recall him turning the transponder on after takeoff. An echo of what you just said.

Yep, in watching the reports on TV, many pilots have said the same things, they need to be able to turn the transponder off while on the ground or in the event of an electrical issue.

The technology used by the airline industry is absolutely cutting edge in some places and very; 1970's in other areas.

This would cost money, but instead of looking for these black boxes in the ocean, they could have real time downloading of all flight data real time and voice recordings to a satellite and then it could be downloaded immediately if a flight went missing. Again, this cost money, but when you consider the money spent looking for this plane alone, it is quite high.

Also, I understand pilots have lobbied to only have the last 30 minutes of their voice interactions recorded in the cockpit, because they say it is a violation of their privacy to record for longer periods. Even if they find the black box, they will only have the last 30 minutes of voice recordings, when the key parts, are what happened when they changed course, but will not be available.

 

[Drekkan85]

Electrical fire.

 

[pgp_protector]

Why Plane Tracking Systems Can Be Turned Off - Business Insider

"In the interest of safety — namely, fire and electrical system protection — it’s important to have the ability to isolate a piece of equipment, either by a standard switch or, if need be, through a circuit breaker," Smith explained.

 

[OGM]

Why Plane Tracking Systems Can Be Turned Off - Business Insider

I am a pilot and I would never fly an aircraft that did not have a transponder "off switch". Here is why

Fire:
A transponder is an electrical device. It is also a transceiver. This means it uses energy and puts out heat. As with all electrical devices, components can fail. If the power supply goes it is possible for it to start smoking and/or start a fire. Hence the transponder has an off switch and a circuit breaker. Even a car radio has a fuse to protect it.

Engine Start:
When starting the engine(s) you often keep the avionics off until the electrical system stabalizes. If you were to start with the avionics on, you could voltage spike and ruin equipment. Or at the very least shorten it's lifespan.

Engine Shutdown:
Likewise you turn off much of the avionics before engine shutdown for protection.

Generator (alternator) Failure:
If a generator or alternator fails the transponder may have to be deactivated to conserve energy...at least temporarily.

Ground Procedures:
In many airports domestically and around the world...you leave the transponder off during ground operations. There are several reasons for this. One is that certain radars can have problems with all of the ground returns. Not all airports around the world have the newer equipment that can read transponders properly from planes on the ground.

Bad Signals:
For several reasons, transponders can need resetting because they not operating perfectly. I have even turned off and on my transponder in New York City traffic because a controller requested it. The controller said, "recycle your transponder," so I did and everything was fine.

Backup:
If your main transponder is having problems and you have backup...you still want to turn off the malfunctioning transponder completely...and then activate the backup. Why would you want the bad unit stuck on while the good unit is on as well. This really could cause confusion on a controller's radar and to other aircraft around you.

FAA Certification:
I doubt the FAA would certify a transponder being installed without an off switch for the above mentioned reasons.

So I completely disagree with removing the off switch to a transponder.

 

[ForJesusChrist]

The real question is, who, why, and where is this plane?!?!

 

[OGM]

The real question is, who, why, and where is this plane?!?!

If I knew I would be the first to tell all of y'all..

 

[ForJesusChrist]

We can only pray for them.

 

[OGM]

We can only pray for them.

So true my friend...so true

 

[ForJesusChrist]

Hopefully, they will come out of the sky one of these days, all safe and sound.

 

[Boss_BlueAngels]

I am a pilot and I would never fly an aircraft that did not have a transponder "off switch". Here is why

Fire:
A transponder is an electrical device. It is also a transceiver. This means it uses energy and puts out heat. As with all electrical devices, components can fail. If the power supply goes it is possible for it to start smoking and/or start a fire. Hence the transponder has an off switch and a circuit breaker. Even a car radio has a fuse to protect it.

Engine Start:
When starting the engine(s) you often keep the avionics off until the electrical system stabalizes. If you were to start with the avionics on, you could voltage spike and ruin equipment. Or at the very least shorten it's lifespan.

Engine Shutdown:
Likewise you turn off much of the avionics before engine shutdown for protection.

Generator (alternator) Failure:
If a generator or alternator fails the transponder may have to be deactivated to conserve energy...at least temporarily.

Ground Procedures:
In many airports domestically and around the world...you leave the transponder off during ground operations. There are several reasons for this. One is that certain radars can have problems with all of the ground returns. Not all airports around the world have the newer equipment that can read transponders properly from planes on the ground.

Bad Signals:
For several reasons, transponders can need resetting because they not operating perfectly. I have even turned off and on my transponder in New York City traffic because a controller requested it. The controller said, "recycle your transponder," so I did and everything was fine.

Backup:
If your main transponder is having problems and you have backup...you still want to turn off the malfunctioning transponder completely...and then activate the backup. Why would you want the bad unit stuck on while the good unit is on as well. This really could cause confusion on a controller's radar and to other aircraft around you.

FAA Certification:
I doubt the FAA would certify a transponder being installed without an off switch for the above mentioned reasons.

So I completely disagree with removing the off switch to a transponder.

From one pilot to another, perfectly stated.

 

[OGM]

From one pilot to another, perfectly stated.

Thank you... Guess to think, I original thought I may have been a little too verbose. Ha!

 

[MarkRohfrietsch]

On the news this morning, they stated that the crash site was located in the southern Indian Ocean, and that they are commencing a search for more wreckage. They have also announced that there are no survivors.

Lord have mercy!

 

[MarkRohfrietsch]

Right now, they need to turn it off when they land, so the plane does not show up on ground controls radar when they are taxing and clutter up radar and make their job more difficult. Also, if there is a problem in flight, electrical problem/fire etc., they need to be able to turn off devices to control the issue.

What they should have on these planes, is a separate device, not used by traffic control, that can be engaged when necessary, to track these planes.

Others have answered why transponders can be turned off; they are correct. You speak of another system; that they have also. They are called Emergency Location Transmitters (ELTs) These have independent battery power and activate automatically in a crash. Bach when I flew they were just coming into use in General Aviation. The early ones worked so well that they sometimes activated as a result of a hard landing, or high G loading during aerobatics. The FBO at our local airport got at least one "do you know where your aircraft is" call a month from the MoT. I think that they have improved greatly since then.

Why they did not function in this case is thus far not known.

Here is a link to info from one company's ELTs for commercial aircraft: ELTs for Commercial Aircraft

 

[OGM]

The ELT will not work underwater because radio waves do not work underwater. The cockpit voice and data recorders are designed to create and audible "ping" when underwater. However the useable listening range is limited. This is especially true the ocean depth is very deep and/or seas are rough. So much background noise.