
Airbus A320 Family Non-Normal Notes [pdf] - Tomte
https://hursts.org.uk/airbus-nonnormal/notes.pdf
======
bhaak
2.13. Computer reset

"Abnormal computer behaviour can often be stopped by interrupting the power
supply of the affected computer."

I didn't expect a more eloquently phrased "have you tried turning it off and
on again" in this manual.

~~~
ginko
Had that happen before a flight once. They said there was some weird behavior
and they'd powercycle the entire plane for a few seconds. Everything went dark
for a bit and apparently it was fine afterwards.

I think it was an Embraer E-170.

~~~
utopian3
I’ve experienced that while on the ground (also an Embraer I think). Was your
experience in the air? I think I’d hold my breath if that happened while mid
flight.

~~~
el_benhameen
While I understand that it's part of the procedure and flying is generally
very safe, I'd be holding my breath, armrest, and fellow passengers with a
vise grip if they power cycled my plane mid-flight.

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rkochman
Regarding a bomb on board: “In the cabin, procedures are laid down for
assessing the risks of moving the device and for moving the device to the LRBL
at door 2R.”

LRBL is “least risk bomb location” and is apparently required by the FAA:
[https://www.faa.gov/documentLibrary/media/Advisory_Circular/...](https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_25_795-6.pdf)

~~~
tyingq
Interesting. Outside of bombs, the most crash survivable area to sit is a
middle seat in the rear third of the cabin.

Since you want the bomb behind the engines to avoid ingesting debris, you
would likely have to put the bomb in this previously "more survivable" area.

~~~
alistairSH
I did not know about the rear third being more survivable. Do you have a
source? Not doubting, just curious why.

~~~
tyingq
Sure. [https://time.com/3934663/safest-seat-
airplane/](https://time.com/3934663/safest-seat-airplane/)

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tgsovlerkhgsel
I found this part about unreliable airspeed indicators interesting: "Thus
flight envelope protections based on airspeed data from unreliable ADRs may
activate. This may lead to pitch inputs from the flight computers that cannot
be overridden with the sidesticks. In this case, immediately switch off any
two ADRs"

Aside from actually having plenty of redundancy to avoid this scenario (this
can only happen if two out of three sensors fail), this is basically the
Airbus equivalent of MCAS. I wonder how well documented (and trained) this
scenario is (and suspect that pilots are a lot more aware of it).

~~~
cesarb
> this is basically the Airbus equivalent of MCAS

I believe the Airbus flight envelope protection uses the same surfaces
normally controlled by the sidesticks, ignoring the pilot inputs (which is
possible because they're fly-by-wire), while Boeing's MCAS uses the pitch trim
(since it cannot ignore the pilot inputs due to them being mechanically linked
with cables).

> I wonder how well documented (and trained) this scenario is (and suspect
> that pilots are a lot more aware of it).

Here's a case of unreliable airspeed in which the _three_ ADRs were turned off
by the pilots:
[https://www.atsb.gov.au/publications/investigation_reports/2...](https://www.atsb.gov.au/publications/investigation_reports/2018/aair/ao-2018-053)
("In accordance with published procedures, the flight crew turned off the
three air data reference systems (ADRs)"), so it does seem to be
documented/trained.

~~~
selectodude
And the 777, which is FBW, has the same control protection as the Airbus jets.
It's that the 737 is a completely obsolete design and duct-taping 2015 tech
onto it was impossible.

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jaclaz
Actual homepage (with some minimal explanation of what it is about):

[https://hursts.org.uk/](https://hursts.org.uk/)

and where there is a "plain" html version:

[https://hursts.org.uk/airbus-
nonnormal/html/index.html](https://hursts.org.uk/airbus-
nonnormal/html/index.html)

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VBprogrammer
Only vaguely related to the original article but I've often wondered what
causes the loud screeching noise as an Airbus 320 shuts down. I did a bit of
reading around it and came to the conclusion it is actually the PTU (basically
a hydraulic motor directly coupled to a hydraulic pump which allows coupling
the hydraulic power between the two systems without risking bringing down both
in the event of a failure) trying to keep the pressure in one system up as the
engine driven pump stops.

Anyone happen to know if I'm correct?

~~~
SpikedCola
You are correct. Here's[0] a great video on the subject if you're interested.

[0]
[https://m.youtube.com/watch?v=SCplhq1xoYE](https://m.youtube.com/watch?v=SCplhq1xoYE)

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UtMan1988
"Removed section with reference to “if engines are running” from Section 9.1,
“Dual engine failure” since this is clearly nonsense. Sorry."

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salex89
I've heard about this procedure, makes me chuckle every time (in case of
volcanic ash encounter).

"Damage to the windshield may necessitate an autoland or landing with a
sliding window open."

~~~
tyingq
The BA flight 9 crew had only a tiny, semi-opaque, portion of the windscreen
to peer through after flying through volcanic ash. Landed safely.
[https://en.wikipedia.org/wiki/British_Airways_Flight_9](https://en.wikipedia.org/wiki/British_Airways_Flight_9)

~~~
morganw
Flight crew did all the right things and saved the aircraft and passengers.
Brilliant improvisation saved the day and the tale made better with post-
incident interviews: 'Moody described it [glide slope calculation] as "a bit
like negotiating one's way up a badger's arse."'

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lultimouomo
At the end of the "Volcanic Ash Encounter" section:

> Damage to the windshield may necessitate an autoland or landing with a
> sliding window open.

Landing while sticking your head out the window is sure going to be
interesting...

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jrwr
I love page 117

"You’re going to need a longish runway. Worst case is if you only have blue,
since you have, at best, accumulator braking and you’re coming in fast due to
lack of flaps. Yellow is better since you have alternate braking, and its
mainly about the lack of slats. If you have green, its not really all that
bad."

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inamberclad
Context for posting this?

In addition, what source is this from?

~~~
mzkply
Context is aviation software has been in the news lately so yNews is geeking
out.

