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-   -   An-148 missing after takeoff from Moscow (https://www.pprune.org/rumours-news/605282-148-missing-after-takeoff-moscow.html)

Kulverstukas 18th Feb 2018 09:03


Originally Posted by PashaF (Post 10056849)
With all respect.
There is fine line between the data you need to process through your mind and clear malfunction warning.

Exactly. So fine line was between warning which they get at takeoff and they have at least 4 minutes to "process it through their mind".

If you want to discuss automation of pilot heating, welcome to aviaforum.ru, there are over 170 pages on this in An-148 thread now.

gearlever 18th Feb 2018 09:04


Originally Posted by PashaF (Post 10056837)
I swear with my electrical engineering diploma, you need like 20$ investment (20000 with certification and such) to install the device which can inform pilots about ice buildup inside a tube.

In use since many years..., called "Ice detector".

PashaF 18th Feb 2018 09:49

Kulverstukas

I am okay with manual switches.
The point is. Regardless to the origin of this malfunction. (Which is so far attributed to the pilots inability to follow checklist and they nonexistent response to the warning lights)
This was a sensor malfunction! Something literally stopped working.
(Moreover, poisoning other instruments with misleading data flow )

This can't be right.
This is critical to flight instrument and you can easily theorize a lot of situation in which the clear knowledge about Pitot tubes malfunction couldn't be substituted by "your speed is messed up" warning.

Kulverstukas 18th Feb 2018 13:52


gums 18th Feb 2018 14:10

Once again we must understand the control laws on these FBW fxlight control systems to come up with or actually determine a "cause".

- Upon determining unreliable air data, the Viper I flew all those years ago used one of two "gain" values depending upon gear up/down. So body rates and AoA became more important in the computer algorithm. We even had one guy flt for 7 or 8 minutes with ZERO air data and no AoA probes due to a 40 pound bird strike on the nose.

- The Airbus longitudinal control algorithm uses pitch attitude and roll to modify the gee command. Also has the AoA input to "keep you from stalling". Such an implementation in this case may have helped a lot depending on all the reversion sequences. Hell, we went thru all this for a year on the "other" thread.

Hopefully, this accident will provide a strng basis for much better training and maybe even some control law improvements as well as better alert indications.

PPRuNe Towers 18th Feb 2018 15:58


The track of 045 is just FR24's incorrect interpretation when, as in this case, an aircraft sends zero values for the two ADS-B airborne velocity components (N-S and E-W).

The absence of any groundspeed in the ADS-B data, once airborne, is for the same reason.
Ignored it as a null as readouts are there for the taxi before takeoff Dave

Rob

gums 18th Feb 2018 16:17

How did the plot get altitude - agl or baro?

guadaMB 19th Feb 2018 08:36

@Kulverstukas

A simple curio: the cockpit shown in your last video is a Russian or an Ukrainian AH-148?
AFAIK there are differences...

Kulverstukas 19th Feb 2018 09:21

RA-61702

Russian (VASO).

ATC Watcher 19th Feb 2018 09:56

Kulverstukas : thanks for that video on the An148 cockpit . The avionics look very " Western": one questions if I may : what is the large red handle for on the left of the FMS ?

Vendee 19th Feb 2018 10:28

Could it be something like a gust lock?

Kulverstukas 19th Feb 2018 12:23


Originally Posted by ATC Watcher (Post 10057879)
what is the large red handle for on the left of the FMS ?

Parking brake

https://img-fotki.yandex.ru/get/4786...70321b5f_L.png

Turbine D 19th Feb 2018 13:33

Thanks Kulverstukas for all your photos and explanations. :ok: They are very helpful to those of us that are technically interested but not pilots...

ATC Watcher 19th Feb 2018 17:37

Thank you Kulverstukas for the explanation . On the aircraft I fly/flew, the parking brake was always a small insignificant grey or black lever. Do you know why it is so prominent in the An148? Is there a specificity that makes it so important ?

And are the forgotten on/switch for the sensors heaters a prominent one(s) of a standard square one with an illuminated bar, like the many that we see on the video.

AmericanFlyer 19th Feb 2018 18:14

I am not a pilot, but why would an aircraft designer not automatically have the pitot heating turned on if needed instead of a manual item on a checklist?

gearlever 19th Feb 2018 18:21

Somewhere here I read AN148 has a pitot heating element which would overheat on grd/still air. But I understand your concern, it's not rocket science to have a sensor in it for temp reg.

BTW even the airbus changes heating mode concerning grd/inflight, but yes it's fully automatic.

cappt 19th Feb 2018 18:31

Pitot heat on when parked will overheat and cause burns if anyone accidentally touches it.
Therefore it needs to be turned on for taxi and definitely on for T/O. Different manufacturers have come to different solutions for handling this. Yes auto on for T/O if not already would seem the most logical and safe.

PJ2 19th Feb 2018 20:06

Kulverstukas, if I may impose on your time, where are the pitot heat switches located, (overhead panel, I suspect, but where?). Also, I assume they are set to "ON" using either the after-start or before-takeoff checklist; would those checklists be available?

I understand each air carrier may develop their own checklists but the manufacturer's checklists would likely be available, would they?

Many thanks per your fine contributions.

Volume 20th Feb 2018 07:00


would seem the most logical and safe.
Logical perhaps, but not neccesarily safe...
The Spanair accident in Madrid was (partly) caused by such an automatic failing.
It probably is a philosophical question, but having the pilot in the loop will increase awareness, any automation creates a potential for being taken for granted, and being missed in case of failure.
So you have to add an automatic monitoring and warning to the automatic pitot heat, just increasing complexity.


it's not rocket science to have a sensor in it for temp reg.
It obviously is... There were such devices many years ago, but their reliability was poor, so everybody switched back to the dumb heatings... Maybe today with solid state devices being able to handle the high power a more reliable, integrated temperature control would be possible.

Flocks 20th Feb 2018 07:07

Plane I currently fly, Pitot heat are with a manual switch overhead panel.
We have 3 differents caution warning (yellow) associated to each heating element.

We switch the pitot on, before takeoff and off after vacating rwy. If taxi is planned to be long in bad ground potential icing condition (Amsterdam rwy 36L for exemple), on cpt decision, pitot heater can be turned on for taxi.

Just to say, I don't see the problems of manual or automatic. If we forgot with the checklist, I ll have 3 big yellow warning. Takeoff without warning is a mandatory SOP in my airline. We will go only if a warning is already known and under MEL.


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