There is a problem that LIDAR does not work in heavy rain as the laser signal is too attenuated while the radar signal will work in all but the heaviest rain but is not good at identifying clear air turbulence. The answer in research was that both should be set up together.

Real issue is that turbulence may be rain wrapped or be sitting just the other side of a curtain of rain waiting for you to fly into it. This is where the human interpretation of the storm structure is needed. Honest research meteorologists will admit that this is not a simple problem every storm is different. This is why the rather less than useful advice is to avoid flying close to Cb. In all areas of the tropics and sub-tropics this would stop flying a large proportion of the time. However, it does lend support to the idea of a 'business trajectory' being used rather than fixed routes based on canned plans.

Weather Radar
 

A great source of wisdom and knowledge is : Archie Trammell
google it ...

Stall warnings on AF447
 

Roseland,
In reference to your post #857, you are incorrect when you claimed that the stall warnings on AF447 stopped shortly after the captain re-entered the cockpit.
The stall warning sounded a total of 75 times during the fall of AF447 to the ocean. By my count, it sounded 29 times after the captain's return to the flight deck. Not once was it acknowledged by any of the crew.
Rockhound

Well the suggestion maybe that the F16 pilot has spent a significant proportion of his time maneuvering his aircraft to extremis of flight envelope in all conditions. A significant proportion of 20k hour commercial pilot time has been spent accumulating an hours actual flying time in every 9hr sector (e.g 30mins landing 30 mins take-off inc departure from ramp), with maybe 50% of the 'hours on type' spent in a 3 axis motion platform. So maybe just a little more than the yoke!

@gums - your posts are real gems, thanks for your insight. I have read them with great interest back in the AF447 days.

Back to the subject, if this Captain was the PF, do you have any idea what type of training he would have received in the Indonesian Air Force? I would think that a fighter pilot would regularly be on the edge of the flight envelopes, but perhaps this is not true with a 2nd-world Air Force? Perhaps his training was limited to bombing runs and BVR interception?

I can't shake the notion that the Captain should have been someone with a chance to recover the plane, having familiarity with FBW and sidestick controls. He certainly wouldn't have 'stirred-the-muck' like the AF447 inputs.

Perhaps one question is, is this another story of the THS going into NU and then the crew forgetting about it when the automatics cut out?

lapp

You might like to consider post 859 re piloting similarities between extreme turbulence and loss of airspeed.

This is an interesting question.

GPS provides a 3D position, it is just that only the 2D position is used normally.
GPS is used (as one would expect) by GPS Landing Systems that provide the vertical as well as lateral guidance. These are made more accurate by ground based augmentation systems (GBAS) but the accuracy is of the order of 8 meters in all directions without GBAS but with wide area augmentation systems (WAAS).

If everyone flew on GPS altitude then the huge (and they are worryingly huge) number of errors caused by mis-set altimeters would go away.

Currently aircraft in cruise follow a pressure level based on 29.92 / 1013 which means as they fly into a low pressure area they descend and in high pressure areas they climb. Crossing some fronts will mean a descent followed by a climb. However, this is keeping them at the same pressure level so might be better for engine economy but that may be lost if the engines reduce thrust in the decent toward a front then increase thrust to climb away from the front.

Some aircraft are using GPS to provide backup speed information by continually cross referring GPS calculated ground speed to airspeed so if the airspeed indicators drop out the GPS system can provide a reasonable airspeed figure.

So expect to see satellite based altitude and speed information continue to creep into aircraft systems.

We have zero knowledge about what happened in this case.
There is zero evidence that the two accidents are even just similar.

Keep banking your drum of hate against a plane maker, and keep making a fool of yourself.

And it's not just 'Asian' crews. Some of the folks I fly with still think it is an entitlement to play video games and watch movies on their tablets while at the controls. After NW 188 overflew MSP five years ago and the feds pulled the pilots' tickets some of this stuff died down but now it's getting worse, not better in my observation.

I started to say something but it was a long trip ahead and some of these folks act like you've taken away their birthday if you mildly imply that the captain is in command. I guess it's a generational culture thing.

Since you are from TN we may have flown for the same airline. Saw a marked difference when I went to the left seat. Stuff I would never do as a F/O without asking the captain happens all too frequently. On a domestic flight, first leg the F/O (PM) pulls out a book at cruise. Next leg F/O (PF) pulls out said book prior to the transition altitude. I tell him to put it away and he ends up pouting for the rest of the trip.

"I have control" is good, but a response of "you have control" is even better. Makes sure everyone is on the same page. It's been a long time since I crewed on a heavy, but I remember that even back circa 1980 the response had pretty much fallen out of use.

Ian W : Ah the famous debate between GPS and baro altitude! Just like enbedded lateral off-set on FMS , those are wonderful ideas but full of hidden (good) reasons not to do it.
Heavily debated during the ICAO FANS meetings, , if my memory is correct ( long time ago !) main reason against was that WGS84 ( the GPS reference ) is a spheroidal while earth is irregular (a "potatoidal" was the name used) and therefore not suitable in some parts/areas of the world.

Another one was that , at the time , the GPS precision mode switch was still in the hands of the US military , and also in addition, many States would not accept to depend solely on it.

Somewhat worrying that the head of the search effort is quoted by the South China Morning Post article as saying that they are hoping to detect the ELT underwater.

Hopefully just a misquote and he really means the recorder ULBs.

You can't get AoA or airspeed from INS.

surely, GPS is absolute and doesn't have to be integrated. Based on that you can even get GS, but airplane doesn't care about GS at all.

AoA vanes and pitot tubes are the only direct measurements of those crucial parameters that can be obtained.

Indeed, but as you say that was a long time ago. Things have moved on significantly since then. The ellipsoid corrections to geoid are taken care of by software corrections for example.

(For the technical: The World Geodetic System 1984 (WGS84) datum surface is defined as an oblate spheroid or ellipsoid, with major transverse radius at the equator. The coordinate origin of WGS-84 is the center of mass of the Earth. This is being replaced in some applications by the Earth Gravitational Model of 1996. The EGM96 geoid varies from the WGS-84 ellipsoid by between +85 and -105 meters. This can be corrected by software with errors reduced to centimeters
see
Evaluation of EGM96 geoid model in the U.S.
The CARIB97 high resolution geoid height model for the Caribbean Sea
Tutorial: The Geoid and Receiver Measurements | Education | UNAVCO
)

We are also now in the position that ATC surveillance is based on GPS (or rather satellite based positioning - includes GLONAS, Galileo etc.). As it is one of the little recognized aspects of the move to ADS-B and C reports for the basis of aircraft tracking that the Air Navigation Service Providers are now becoming reliant on GPS.

You seem to dismiss this pilot input as inconsequential. Any sustained nose-up input for nearly a full minute in which auto-trim engages is reckless, no?

"Would the automatics eventually recover from any condition resulting from a jet upset? Stall/Spin? Inverted?"

Unlikely, since there are an too many permutations of logical states. In other words - the system is too complex to cover for all possible outcomes.

The only definitive proof that it could would lie in math field - prove it in math - it is 100% guarantee,

One counterexample also - Bus stall warning shutting itself below 60kt threshold, since the AoA readings rendered invalid/inacc. I doubt designers predicted/ thought about that )

Ernie Gann had the answer . .
 

from his book FATE IS THE HUNTER paraphrased somewhat and extracted in describing crashes ..

At these times, Gann says, "... diligently acquired scientific understanding is suddenly blinded and the medieval mind returns. In describing NTSB investigations of crashes, a cause always has to be arrived at, even when the investigators privately know that the true explanation is that "...some totally unrecognizable genie has once again unbuttoned his pants and urinated on the pillars of science". :suspect:

French Copilot p2f background
 

Here's the gentleman's background. He was a graduate of a very tough engineering university (CalTech or MIT level), held managerial post at TOTAL, then indeed p2f. Not taking sides in this debate, just providing info:

"Quand la filiale de la compagnie malaisienne est venue, en 2012, en Espagne chez CAE Global Academy organiser des sélections de pilotes de ligne, l’APPAG a présenté les élèves de sa première promotion qui venaient de terminer leur cursus. Rémi Plésel a fait partie des candidats. Ils ont été six à être retenus par Air Asia Indonesia. Ils ont signé un contrat de trois ans. Le quadragénaire totalisait alors 850 heures de vol, affirme son ami. Des heures qu’il avait financé lui-même, avec son salaire, pour entretenir ses qualifications. « Il allait souvent voler aux Etats-Unis ». Il a notamment effectué son mûrissement au pilotage à l’école de pilotage de la compagnie aérienne Delta Airlines, à Sanford (Floride)."

Vol QZ 8501 : Rémi Plésel, un copilote engagé - AéroBuzz : Actualité et Information Aéronautique

What you say is true - as an instantaneous measurement. But if for a period of time I have ground speed and track from GPS and airspeed from a pitot tube then I can calculate the ambient windspeed and direction. If the pitot sensed airspeed drops out - I can generate and display an airspeed based on the ground speed from GPS and the previous windspeed and direction. In most cases this will be near enough to provide the pilot with sufficient useful information. Add the pilot selecting the appropriate 'pitch and power' for cruise to that and in most instances the information is sufficient to recover the aircraft. This is on the assumption that there will not be gross changes in wind speed/vector in the short period of time before the air driven sensors come back on line.

Ian W On the horizontal plane, absolutely ,( GNSS is the "politically correct" term ), but the altitude part of ADS is still derived from Mode S transponder altitude, whose encoder is barometric, and unlikely to change in our lifetime if you ask me .

lapp

I was under the impression that the aircraft was flying towards a known band of weather, had asked for a level change and shortly after this contact was lost.

In my first post and for the benefit of non pilots I was simply outlining the piloting actions I was taught (many moons ago) in the event of encountering extreme turbulence or loss of airspeed indication.

If you see that as me banging a drum of hate I can only apologise for confusing you.

You are assuming 2 things; that SatNav gives horizontal speed and ignores vertical speed components and that SatNav is unaffected by environmental aspects such as electrical weather systems. Existing Integrated INS gyros do all this successfully in vehicles such as submarines to space craft.

Lateral offset is SOP these days in the SLOP program, not sure why you wouldn't want to do it. :confused: A good overview here: https://ivao.aero/training/documenta...P_SEC_SLOP.pdf

Also, you almost always get lateral offsets flying in Chinese airspace, I don't see how you could avoid them. These offsets seem somewhat random and are not always to the right side. Sometimes you even get them on SID's and have to invoke some FMS magic to make them work.

"I have ground speed and track from GPS and airspeed from a pitot tube then I can calculate the ambient windspeed and direction"

Right, but it is not the same as getting airspeed from GS, since in that case you have to get GS(gps velocity), last wind readings and you have to have a really nice INS that would give precise enough acceleration measurements (not INS for 150$) so that when you feed all that stuff into some sort of soph. alg (kalman filter or smthg), you would get correct(more or less) "airspeed" reading.

In the lab that I am working in (university lab - aerospace/engineering dept) we got INSsa that cost 10 times as $150 and it's not as precise for supporting that kind of model of obtaining airspeed as it should be.

What I was arguing about is -> $150 might not be enough. :8
-------------------------------------------------------------

"If the pitot sensed airspeed drops out"
caution - conditions that determine that "drop out" might be vague. :}
It is probably easier to let this thing to be decided by a pilot.
-------------------------------------------------------------

If am not mistaken, at least B787 have that mode in which it derives airspeed from gps and (I am assuming, by using INS too). In that video the difference in airspeed and calculated "airspeed" was around 5 kts. But, again - not with a $150 solution )

1500 hours on basic airplanes with no or little automation,ideally flown as an instructor constantly practicing stalls and basic maneuvers are a background that no AFDS protection can substitute. Stop P2F and enforce such rule worldwide or more and more people will die. If I had to start an airline I would only hire pilots with FI rating and experience. The US are as usual leading..just follow and take geniuses with no real skills and no qualities other than daddy's money out of airliner cockpits .

"but the altitude part of ADS is still derived from Mode S transponder altitude, whose encoder is barometric"

Not always.
At least, ADS-B format retains both ways of reporting barometric as well as gps altitude. Different bit flags in the ads-b message need to be used in order to distinguish different readings.

At least, that is what I got from reading technical docs on the ADS-B message format.
:)

The FO was a P2F? And a midlife career change at that - usually the very worst candidates for a professional flying job are the career change guys. If you don't start this profession at an early age, the innate skills aren't firmly planted.

A factor? We won't know until the CVR turns up.

Question for heavy metal pilots from a light metal pilot:
Many posts seem to be something like "a thunderstorm should not be able to take down a modern jet". Down at the lower levels we are all taught a thunderstorm may very well be beyond the ability of the airplane to stay in one piece and to avoid them if at all possible.. I have been through a couple that were rather sporty with 2,000 FPM + climbs at idle thrust and rain like flying under Niagara Falls. It would certainly be a handful for anyone not on top of their game.
Is the SOP in that area of the world to just blast through it or ????

Of course.

I was just pointing out that the basic surveillance by ATC is slowly moving to dependence on GPS (GNSS's). This was the answer to the point about the precision switch being in DOD hands. This is mitigated somewhat by WAAS and LAAS which may be the reason that the precision switch is not so critical and discussed these days.

I don't think I would describe the FO as P2F. The article linked only states that he financed his licenses and the A320 TR himself through his salary as a manager at TOTAL. It doesn't say anything about a P2F situation in his employ at AirAsia.

No. Avoid, avoid, avoid. It has become especially important with the Airbus product, most recently in regard to the LH experience involving frozen AOA vanes, loss of aircraft control, and the subsequent generation of an emergency AD to all operators.

We seem to be spending a lot of effort these days trying to outwit all of the 'gotchas' the system designers overlooked.

It is normal these days to integrate the INS and the GPS so that any wander in the INS is corrected and any outage of GPS can be covered by use of INS.

It is not a perfect system but it can provide a pseudo airspeed indication. Had it dropped in when the AF447 ADIRUs lost the plot and they just picked up a generated airspeed instead the FMC could have stayed in normal law with just an ECAM message of the airspeed sensor failure, then when they came back a minute later - the system could have reverted. I believe (someone may confirm) that the 787 has something like this built in.

He was born on the Caribbean island of St. Martin, and graduated from the Universite Pierre et Marie Curie in Paris (UPMC is part of the Sorbonne). UPMC is well-regarded in the sciences, it does offer engineering, but I believe the Sorbonne's principal engineering school is the Université de Technologie de Compiègne. Supposedly English fluent.

On Twitter, purported to be leaked radar screenshot:

https://twitter.com/TheGlobalflight/...159424/photo/1

This is interpolated radar data from a refresh rate of probably a couple of seconds.
Geo vertical rate is not available from Mode-S nor is Ground Speed or Track with a resolution of 1/100.
Nothing worth in my eyes.

According to the link posted, he did not graduate from either, but Ecole Nationale des Ponts et Chaussees.

As to Université de Technologie de Compiègne, I don't believe it is anywhere near the same level. Engineering at UPMC look fairly good OTOH.

Airbubba : we are talking 2 different things, I was reffering to the global 0.1NM EMBEDDED in the FMS to counter GPS nav accurracy. ( disccussed in ICAO on initiative IFALPA ATS committe after the Sioux Lookout collision in 1995.) long debate about it, also here on PPrune . But off topic .

Sunamer:Yes but the ICAO standard chosen was Mode S/Baro, not the GPS Alt. No single a/c ADS equipped flying today uses and transmit GPS Alt.

Ian W : Agreed , and this will disapear completely with Gallileo coming in. However a future hypothetical switch from barometric to GPS Alt would have to be globally coordinated on a specific date ( similar to RVSM) and old airframes retrofitted, which has always been THE main problem , especially on your side of the Atlantic (since you still use Jurrassic jets overthere:E)

@AirScotia

The location given places PK-AXC about 17 miles south of the earlier reported LRP.
It is also about 6 miles west of the location given on George Hatchers' site.

I can't imagine where these minor discrepancies are coming from - unless someone is trying to trace leaks.

furbpilot said



"1500 hours on basic airplanes with no or little automation,ideally flown as an instructor constantly practicing stalls and basic maneuvers are a background that no AFDS protection can substitute. Stop P2F and enforce such rule worldwide or more and more people will die. If I had to start an airline I would only hire pilots with FI rating and experiencdr. The US are as usual leading..just follow and take geniuses with no real skills and no qualities other than daddy's money out of airliner cockpits ."


With you there :ok: , but, the problem is the "suits"/ accountants ain't gonna let it happen, as FO's are now a revenue source too, and, well, one or two crashes every couple of years is still affordable . . . right ? :}

AirScotia: I agree with Threemiles, this is not a Mode S Extended Squitter data block. So this was not transmitted by the aircraft.

If this is genuinely coming from inside AirNav indonesia , then maybe a track extrapolation of the flightplan processing system. But guesswork.