Dear friends and followers, welcome back to my channel,
and to a video about the famous "Black Box"
you've certainly heard about after any recent airplane incident.
We'll be looking at it in close detail: its primary functions,
why it's placed at the back of the plane, why is it orange,
and what's that got to do with a dropping water bottle?
So let's start recording!
Sadly after any airplane incident or crash involving
numerous victims, the media is all over it
and you very often hear the reporters say:
-"...their urgent search for the black boxes: the Flight Data and Cockpit Voice Recorders..."
-"...recently detected are from the planes black box."
-"...Yes. Its apparent discovery of one of the black boxes comes on them..."
- So what is this black box they always seem to be looking for?
Now, the black box is very often actually split in two black boxes,
which will help the investigators to determine what and how it led to the accident.
Each box roughly weighs 20 pounds and each have the size of a shoebox.
One of them is the CVR: the Cockpit Voice Recorder.
Now, picture a classic tape recorder with four microphone cables attached to it:
one leading into the radio control panels to record any communication between
the pilots and the air traffic controllers,
one recording all conversations via the intercom within the cockpit,
and another one leading to the overhead panel microphone,
recording ambient sounds of the cockpit such as engine sounds and oral warnings.
- When does it and how much does it record?
It automatically starts recording in flight and on ground,
when at least one engine is running, and
for a few minutes after the last engine was shut down.
But on most planes you have the option to manually start the CVR
by pressing a button on its respective panel.
The CVR records the last two hours of crew conversation and communication with ATC,
so whenever you arrive at the gate and shut down the engines,
you could listen to the last two hours of conversation;
well you can't really within the cockpit, you would have
to detach the recorder from its housing and place it into like a special docking station to listen to it.
Funny enough, Airbus and Boeing models have a CVR erase button.
Once you press that, all the latest recordings get erased.
I recently flew with a captain who asked:
"Man have we talked any smack about our CEO in the last two hours?
Nah, better delete the recordings anyway",
and he just pressed the button!
The other recorder, or the second black box is the Flight Data Recorder.
Now the Flight Data Recorder, also known as the ADR: the Accident Data Recorder
records data at a much larger scale than the CVR.
Now, the FAA regulates that the FDR must monitor
at least 88 important parameters such as altitude,
airspeed, heading, aircraft attitude, for a minimum of 25 hours.
Nowadays, FDR's made by Honeywell, for instance, can record up to
1000 inflight parameters and characteristics such as the flap position, the autopilot modes,
weather radar readouts and much, much more to aid the investigators.
Now, this then allows the retrieved data from the FDR to generate a computer animated video
reconstructing the flight before and during the crash, which then can look very similar to this animation.
So the combination of the visual part by the FDR and the audio by the CVR enables a realistic picture for
investigators, so with the collected data from both recorders the
investigators then determine whether an accident was caused by pilot error,
by an external event such as a wind shear for example,
or an airplane technical failure.
-"Cactus 1549, turn left heading 270"
-"Uh... this is uh Cactus 1549, hit birds, we've lost thrust on both engines, returning back towards La Guardia"
-"Okay, you need to return to La Guardia, turn left heading 220."
- Why is it often placed near the tail of the airplane?
If you look at airplane crash investigation footage you very often see
the tail cone and the rudder intact compared to the rest of the wreckage.
Why is that so?
Now, the aft section of the plane is structurally much stronger than
other parts of the plane as the metal panels all come together,
needing overall more stringers and framing,
which stiffens the tail cone section.
Therefore my German physicist has come up with
a great experience using a water bottle to show you the stiffness of the airplane's tail cone.
Now, we are imagining that the glass bottle is our airplane with the
bottleneck being the tail cone section of the airplane.
Due to the manufacturing process of the glass bottle,
the bottleneck is thicker due to its narrower diameter,
making it stronger than the rest of the bottle
and remains intact after applying force to it,
similar to the tail cone after a crash landing.
So it makes sense to place the black box back here then, right?
Well by just placing it here won't make it unbreakable.
That's why the recorders are in a box wrapped in strong corrosion resistant,
stainless steel or titanium, giving it an impact tolerance of
3,400 G's, and with a high temperature insulation it can resist
1,100 degrees Celsius for 30 minutes.
But even more important is this little tube
you see at the side of most FDR's.
Now, this is the underwater locator beacon, that emits an ultrasonic 'ping'
every second to aid in detection when submerged under water.
Now these beacons operate or transmit on a 37.5 kHz frequency
for up to a minimum of 30 days and are able to operate
while immersed to a depth of up to 20,000 feet
Please do not mistake this with the ELT
That's a whole nother story.
So how do they find the black box? Unfortunately,
it requires a lot of time and effort to narrow down the estimated location of the crashed plane,
especially in our oceans, but once the estimated position
is evaluated, they deploy a so-called pinger locator.
Now, this device will be towed behind a search-and-rescue ship, looking to pick up the signal emitted
from the pinger. Sadly, these devices are
extremely expensive and fragile and only a few of them exist.
- And the last question:
"Why is the box orange or red and not black hence its name?"
Now, there are a few rumors about this one.
Now one explanation, calling it a black box comes from
the early film-based designs of the flight data recorder,
which required the inside of the recorder to be perfectly dark
to prevent light leaks from corrupting the recordings, comparable to a
photographer's darkroom. Others say that during
the Second World War the Brits equipped their bombers fighting the Germans with
prototype flight data recorders which were handmade
metal boxes, painted black to prevent reflections
and after time any piece of new electronics was referred
to as the 'box of tricks' like an illusionist's box, or the black box.
Nowadays they are painted in bright orange red heat-resistant colours
to make them easier detectable in all the white-greenish debris.
"Old vs. new recorders":
Now, also interesting to know is that former CVR's and FDR's
actually were recording onto magnetic tapes similar to the ones in a classic tape recorder,
but over time they became more and more prone to vibrations,
and often the data was lost or damaged if the plane had crashed into water,
due to humidity building up within the box.
So the latest designs nowadays use solid-state memory similar to an SD card,
and digital recording techniques, making them much more resistant to shock,
vibration and moisture. By the way,
one of the best movies to watch regarding readouts from the black box is "Sully". You could say besides his
outstanding performance as a pilot, the black box actually saved his reputation as a pilot,
but see for yourself. One more thing
I want to point out here is that I very often get asked to do reviews on recent airplane crashes
I can't and I won't be doing such videos as I'm a pilot and not an airplane crash
investigator. Other channels do that, I find it very
disrespectful towards victims and loved ones as they are trying to gain views,
due to the media attention latest crashes are receiving.
Just wait until the final crash report is out. They are sad enough, but these guys really know what they're doing
That's it for today. Thank you very much for your time.
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And don't forget, a good pilot is always learning.
See you next week, all the best, your Captain Joe.