Help In Understanding Data Options

[Tashi]

Hello to all! I would like to ask where to find the information Rob asked the manufacture of the flight data recorder. For some reason I remember it as a Podcast conversation or maybe I just read it somewhere.
Rob if your reading this, Clinger is acting up again with some very specific questions about lag time data being unreliable on the FDR etc. A couple responses from you might seal the deal with him. Only if your up for it.
Tashi

[Tashi]

Can someone help clarify what this guy is telling me? Thanks Tashi



It ain't that simple.
The NTSB animation is not primary evidence. It is
a tool for visualizing what happened. To the extent
that the animation was derived from the FDR data, it
is redundant with FDR data. To the extent that the
NTSB animation extends the FDR data, it represents
someone's interpretation (theory) of what happened,
presumably based on additional evidence not contained
within the FDR data.
Furthermore, some of the FDR data (certainly position
and time, possibly altitude) require calibration
adjustments to resolve systematic discrepancies
between FDR and radar data. A certain amount of
subjective human judgement goes into that.
No one outside the government has physical access to
the FDR itself [1]. The FDR data are available to
the public only in the form of computer files [2].
There are actually two distinct computer files, an
FDR file that requires special software to decode,
and a more convenient summary called a CSV file.
The CSV file should have been derivative of the FDR
file, but the CSV file has been reported to contain
one extra data point at its end [3,4]. If true,
that means the government once had access to an FDR
file that is more complete than the one that has
been made public. Whether the government still has
that file and how much more data it contained are
unknown.
At least three investigators have reported that the
last data point contained within the FDR files puts
the plane on the order of a mile away from the
Pentagon, several seconds before impact [3,4].
The position, time, and altitude for that last data
point depend on exactly how the data were calibrated,
which is slightly subjective.
It takes time to transfer digital data from fast
volatile buffer memory to nonvolatile memory, so
we would expect to lose the last few data points
before a crash. The particular model of flight
data recorder that was used on Flight 77 wasn't
supposed to lose more than a second or so of
data, but maybe it did. It was a bad crash.
There are mysteries here. It ain't simple, and
people who want all mysteries to be resolved in
the final chapter are going to be disappointed.
Will

[rob balsamo]

http://pilotsfor911truth.org/forum//index....showtopic=10751

[rob balsamo]

Recording with Ed Santana of L3 Communications is in this video...

http://video.google.com/videoplay?docid=2833924626286859522

I forget exactly where. I spoke to Ed and did the recording myself.

Here is also an email exhange with L3...

What would be a typical time lag between the sensor signal being
generated (for example aileron angle) and the data being logged to the
protected memory of the recorder?

L-3 Response: Per ED55, it shall not exceed 0.5 seconds,

Is the size of this recording delay regulated by industry or just
minimized by good design?

L-3 Response: Regulated per ED-55, Minimum Operational Performance
Specification for Flight Data Recorder Systems.

In the case of a major accident like CFIT (controlled flight into
terrain) how much data (in terms of seconds of flight) is typically
lost? (For example signals still being processed by the DFDAU).

L-3Response:

With the use of the Solid State Flight Data Recorders,
typically, data is only lost at the point when power to the recorder or
FDAU is terminated.

[rossgs]

How frequently are these instruments sampled and sent to the FDR? Is the information bus like and ethernet or more like a token ring networK? Is there any link to a manufacturers website or something from the FAA explaining the inner workings? (may be rhetorical as I haven't found one)

Recording with Ed Santana of L3 Communications is in this video...

http://video.google.com/videoplay?docid=2833924626286859522

I forget exactly where. I spoke to Ed and did the recording myself.

Here is also an email exhange with L3...

What would be a typical time lag between the sensor signal being
generated (for example aileron angle) and the data being logged to the
protected memory of the recorder?

L-3 Response: Per ED55, it shall not exceed 0.5 seconds,

Is the size of this recording delay regulated by industry or just
minimized by good design?

L-3 Response: Regulated per ED-55, Minimum Operational Performance
Specification for Flight Data Recorder Systems.

In the case of a major accident like CFIT (controlled flight into
terrain) how much data (in terms of seconds of flight) is typically
lost? (For example signals still being processed by the DFDAU).

L-3Response:

With the use of the Solid State Flight Data Recorders,
typically, data is only lost at the point when power to the recorder or
FDAU is terminated.