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Indonesian aircraft missing off Jakarta

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Indonesian aircraft missing off Jakarta

Old 31st Oct 2018, 16:28
  #321 (permalink)  
 
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Originally Posted by Volume View Post
What is most ridulous is that in 1988 most pilots would have easily handled such situation...
Not 8 years later... https://en.wikipedia.org/wiki/Aeroper%C3%BA_Flight_603
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Old 31st Oct 2018, 16:36
  #322 (permalink)  
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Originally Posted by jurassicjockey View Post
Available on the HUD on the 787 within 5 degrees of stick shaker. I would have assumed that the MAX would have the same if equipped with the HUD
AOA is the angle between the FPV and the aircraft pointer on the ADI on FPV equipped 737s (and 777s)

Last edited by AfricanSkies; 31st Oct 2018 at 16:56.
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Old 31st Oct 2018, 16:39
  #323 (permalink)  
 
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Originally Posted by AfricanSkies View Post
AOA is the angle between the FPV and the horizon on the ADI on FPV equipped 737s (and 777s)
You mean nose symbol and not horizon?
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Old 31st Oct 2018, 16:53
  #324 (permalink)  
 
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Originally Posted by gums View Post
The air data sensors appear to be just behind the radome and access panels for the radar. There's possibility of contamination or even a "loose" pnematic line depending upon the actual configuration of the air data sensors.
Yes - specifically the LH ADM needs to have the pitot input disconnected to gain access to the radar.

GOL nearly lost a B738 seven years ago. Fresh from the factory, a radar failure required a software reload. When the technician reconnected the pitot hose, the connector was engaged, but not twisted in the bayonet fitting to lock it. The result was intermittent UAS, with vertical excursions even more extreme than the Lion Air.

That the crew and pax survived to tell the tale was, according to the report, largely due to a deadheading captain on the jumpseat who exhorted the PF (and the check captain in the RH seat) to "fly the d*mn airplane" (or words to that effect in Portuguese).
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Old 31st Oct 2018, 16:55
  #325 (permalink)  
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Originally Posted by Vessbot View Post
You mean nose symbol and not horizon?
I do, thanks, I'll change it
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Old 31st Oct 2018, 17:53
  #326 (permalink)  
 
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Meanwhile Lion Air has sacked its technical director.

The company said its dismissal of Muhammad Asif had come on the orders of the transport ministry.
AVHerald quotes more updated sources saying that he's actually been suspended for 120 days. Not that I expect that this will make a whole lot of difference in the end.
Sounds like they have found a fuse to blow in the company. If this guy has been cutting corners, that probably wasn't without the (possibly unwritten) orders from the bigger bosses...

Last edited by alainthailande; 31st Oct 2018 at 17:54. Reason: Correction
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Old 31st Oct 2018, 18:06
  #327 (permalink)  
 
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Originally Posted by EDLB View Post
Did they find the FDR and CVR in the meantime? Can‘t be that difficult in 30m tropical water. Without their data all is pure speculation.
Appears that they're homing in on them - but even tropical waters have nasty currents: https://www.theguardian.com/world/20...jets-black-box
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Old 31st Oct 2018, 18:44
  #328 (permalink)  
 
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There are many reports saying that they have picked up the pings and found the main wreckage.
Navy officer Haris Djoko Nugroho said the 22-meter (72-foot) -long object that could be part of the fuselage is at a depth of 32 meters (105 feet). He said divers will be deployed after side-scan sonar has produced more detailed images. He said it was first located on Tuesday evening.
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Old 31st Oct 2018, 19:05
  #329 (permalink)  
 
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Salute!

Huge Thanks, Dave Reid. and @ Bloggs.

That is exactly where my analysis was headed. I have been on numerous accident boards, mostly flight control suspicions until the final investigation was completed. There was always the pilot error factor, but I always leaned toward something that the poor dude had not thot of, or practiced or.... I used to sit in the barber shop or the waiting lines at the dispensary and try to come up with the worst case and then what would I do. Kept me alive for a few combat tours and several equipment failures in one or more of my jets. So it ain't always "luck" Luck is when preparation meets opportunity, huh?

I still have feelings about that crew, and reminds me of Air Alaska.

Gums opines...
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Old 31st Oct 2018, 20:01
  #330 (permalink)  
 
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Originally Posted by LandASAP View Post
So we (maintenance) aren't doing our job if the crews tells us something and not doing an Logbook Entry? Ridiculous comment!

It is quite often the case that the crews tells us, that something was wrong and after a look in the book there is not Entry. Belive it or not but we nevertheless have a look onto it.
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Old 31st Oct 2018, 20:08
  #331 (permalink)  
 
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Originally Posted by edmundronald View Post
Not a pilot, feel free to delete ...

Absent airspeed indications, I would expect pilots to set throttle and AoA for stable flight, declare an emergency, get an estimation of windspeed from ground, point a Mark I Eyeball out the window on that pointy end, and use the compass, radio altimeter and groundspeed indicators to navigate back to the airfield, and land - surely with a 5mph ground wind, and decent weather, a visual-only landing is a possibility?

I know that flying is hard and requires specialist training but if visual flying of a modern airplane in good conditions at 5000ft has become impossible for trained pilots with 5000 hours, then maybe this is an issue for input to the politicians and not to be left for the industry to bury in the name of "self-regulation"? Or is the "blocked vents ==> mass funeral" scenario now going to be played out every few years?

AF447 was a wake up call on the effects of bad airspeed indications ...

I think those smart guys with sliderules in Seattle and Toulouse are perfectly capable of making planes that can be flown by hand when necessary, provided the customers or supervisory authorities ask nicely.

Edmund
Edmund,

You make some good points, albeit scattered with understandable inaccuracies owing to your lack of insight.

Firstly, many heroes on here will shout "fools", without understanding that sometimes the diagnosis of UAS is difficult. In essence, you see something that doesn't make sense. The pitch/power/speed relationship is wrong and the FD is doing something odd. A modern pilot is suckered into believing the FD, and may have trouble working out which parameter is out - and may decide to disbelieve the pitch (for example).

Once diagnosed as UAS, we have trained procedures that are designed to work IFR. It's no good relying on anything visual, as you may not have it - and even if you do it can be fatally misleading. But most procedures are the same - establish onto a known flightpath (often a climb thrust with a certain pitch) while you get the book out and find some settings to level out when above MSA. From there, you can carefully plan and then execute a stable instrument approach. It's hard work, but if trained well and practised regularly, not the end of the world at all.

Your final point is also interesting. It's very easy for an airline to employ pilots who, through no fault of their own, are only well-versed in normal operations with high levels of automation (including FD etc). In the old days, pilots flew normally with low levels of automation (my first commercial aircraft had no map, autopilot, autothrust and so on). So losing ASI was obvious, and all the pitch/power settings were known and used daily. Nowadays we don't have that, so it has to be well trained and practised in the simulator. This is expensive and difficult, and requires wealthy airlines with good safety culture. This is hard to legislate for.
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Old 31st Oct 2018, 20:49
  #332 (permalink)  
 
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Originally Posted by gearlever View Post
What about the ADS-B data are from the same faulty air data source displayed in the cockpit?
Altitude may be, depending on whether it's the faulty side that's feeding the Mode C/Mode S transponder, though it doesn't seems to have been an issue in this instance.

ADS-B groundspeed and track aren't from an air data source, so aren't affected.
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Old 31st Oct 2018, 20:51
  #333 (permalink)  
 
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From way back in the thread

Its not pitot but static...static vent blocked.Airspeed will indicate normally on takeoff but underread in climb.Altimeters will remain stuck after takeoff.Its a nasty little scenario and could easily lead to confusion.The subsequent loss of control could be explained by the high speeds with flaps still down(crew distraction and onset of panic).
If it happens(altimeters dont show climb after liftoff,you get windshear warning(false) and.or stick shaker(false) you have to climb to 1500' on RADIO ALTIMETER, level off, set 60% N1,ignore the warnings and LAND immediately,either visually or on vectors.
So let us assume that is the case and the advice given here was not followed the aircraft is in almost level flight at 5000ft with mud wasp nests (or whatever) in the static vents. The crew have taken over manually and are almost controlling the aircraft with pitch and power with a hazy horizon but things are calming a little. If the autopilot were to be reengaged what would happen?

Would the FMS with UAS demand to climb and accelerate while the STS was running opposite direction (as per previous flight). As the aircraft rapidly climbs the crew re-disconnect autopilot or it disconnects itself. Could the crew be given an aircraft at the top of a zoom climb with full thrust and a lot of ND trim bunting into a 25 - 30degree nose down power dive at the ocean?
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Old 31st Oct 2018, 21:19
  #334 (permalink)  
 
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The B737 Max is the first generation of B737’s to have fly-by-wire spoilers, I am curious as to what inputs these use and how they might have contributed to any accident?

Anyone have further details of this system on the Max?
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Old 31st Oct 2018, 21:41
  #335 (permalink)  
 
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My 2cents worth, Autopilot engaged AFTO, stayed engaged till impact.
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Old 31st Oct 2018, 21:45
  #336 (permalink)  
 
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Originally Posted by HundredPercentPlease View Post
Edmund,

You make some good points, albeit scattered with understandable inaccuracies owing to your lack of insight.

Firstly, many heroes on here will shout "fools", without understanding that sometimes the diagnosis of UAS is difficult. In essence, you see something that doesn't make sense. The pitch/power/speed relationship is wrong and the FD is doing something odd. A modern pilot is suckered into believing the FD, and may have trouble working out which parameter is out - and may decide to disbelieve the pitch (for example).

Once diagnosed as UAS, we have trained procedures that are designed to work IFR. It's no good relying on anything visual, as you may not have it - and even if you do it can be fatally misleading. But most procedures are the same - establish onto a known flightpath (often a climb thrust with a certain pitch) while you get the book out and find some settings to level out when above MSA. From there, you can carefully plan and then execute a stable instrument approach. It's hard work, but if trained well and practised regularly, not the end of the world at all.

Your final point is also interesting. It's very easy for an airline to employ pilots who, through no fault of their own, are only well-versed in normal operations with high levels of automation (including FD etc). In the old days, pilots flew normally with low levels of automation (my first commercial aircraft had no map, autopilot, autothrust and so on). So losing ASI was obvious, and all the pitch/power settings were known and used daily. Nowadays we don't have that, so it has to be well trained and practised in the simulator. This is expensive and difficult, and requires wealthy airlines with good safety culture. This is hard to legislate for.
HundredPercentPlease
You are saying that *by design* a single blocked orifice (pitot or static vent) can put the pilot's control systems in a state such that conventionnally trained and certified airplane pilots will quite reasonably be expected to lose control and terminate in an encounter with terrain at speed, even though control surfaces and engines are fully functional. As an engineer, I would call this a clear case of absence of redundancy, and cannot understand that such a design would obtain certification.

My impression is that in current generation aircraft there are now more fatalities arising from airspeed instrument anomalies than from uncontained engine failures.

Please forgive me for again stating the obvious, but it may be time that some adults were brought in to revise instrumentation design in a world in which more and more pilots are needed to fly more and more airliners, and the actual mechanical systems have become very reliable.

Edmund

Last edited by edmundronald; 31st Oct 2018 at 21:55.
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Old 31st Oct 2018, 21:53
  #337 (permalink)  
 
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CORRECT
strange pitot fantasy
Originally Posted by edmundronald View Post
HundredPercentPlease
You are saying that a single blocked orifice (static vent) can put the pilot's control systems in a state such that conventionnally trained and certified airplane pilots will quite reasonably be expected to lose control and terminate in an encounter with terrain, even though control surfaces and engines are fully functional. As an engineer, I would call this a clear case of absence of redundancy, and cannot understand that such a design would obtain certification.
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Old 31st Oct 2018, 21:59
  #338 (permalink)  
 
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Originally Posted by ULH Extreme View Post
My 2cents worth, Autopilot engaged AFTO, stayed engaged till impact.
That could very well be true, and it would be a shame, as the first two items on the airspeed unreliable checklist are autopilot and autothrottles disengage. They are also items two and three on the runaway stabilizer checklist after grasp the control column firmly.


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Old 31st Oct 2018, 22:08
  #339 (permalink)  
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Would using CWS in this situation assisted.
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Old 31st Oct 2018, 22:11
  #340 (permalink)  
 
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Originally Posted by edmundronald View Post
HundredPercentPlease
You are saying that *by design* a single blocked orifice (pitot or static vent) can put the pilot's control systems in a state such that conventionnally trained and certified airplane pilots will quite reasonably be expected to lose control and terminate in an encounter with terrain at speed, even though control surfaces and engines are fully functional.
No, I am not saying that.

I am a "conventionally trained" pilot that has many thousands of hours on both the 737 and the A320, and not once during numerous UAS experiences in the sim have I done anything other than applied the procedure and resolved the scenario.

What I am saying is that for a modern pilot exposed only to modern aircraft, this requires good quality training, and that good quality training is not something that all airlines provide.

From an engineering perspective, modern aircraft have many protections, systems and displays that rely on accurate input data. If the input data is erroneous, then the very system that is designed to protect you, can do the opposite. The STS in the 737 is one. The A320 has plenty. So a simple failure like UAS can become horribly complicated - don't underestimate this.

[Edited to add: I'm sure you are aware, but modern types do have an engineering solution to this pitot/static failure, the A320 series has a backup speed scale which is derived from AoA and works very well]
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