Maybe reading NPA 2011-03 will give you some idea.
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An international working group (led by the Aviation Rulemaking Advisory Committee (ARAC), tasked by the Federal Aviation Administration (FAA), USA) worked between 1997 and 2009 to prepare recommendations for a regulation change. (...)
The proposed rule would require consideration of the SLD icing conditions (freezing drizzle and freezing rain) defined in the proposed new CS-25 Appendix O, part I, in addition to the existing CS-25 Appendix C icing conditions. The proposed Appendix O was developed by the ARAC IPHWG, which included meteorologists and icing research specialists from industry, FAA/FAA Tech Center, Meteorological Services Canada, National Aeronautics and Space Administration (NASA) and Transport Canada/Transport Development Center. The IPHWG collected and analysed airborne measurements of pertinent SLD variables and developed an engineering standard to be used in aircraft certification.
HN39, thaks for the link. I haven't read all the 77 pages yet. But... at first sight it deals with 'low-level" icing and the ATR-72 accidents, not with the problem of the certification problems of pitot tubes in hi-alt icing conditions (which are not the same). So far, in all the discussions, I've not yet seen a mention of even a 'proposal for rule making' to replace the obsolete certification rules for pitot tubes.
BTW, I'm ignoring jcjeant's waffle and interference - he's obviously got his own troll agenda.
Ahhhhh.....humans. If I could change one thing, and one thing only, it would be the cessation of the stall warning at whatever values of AOA and airspeed were inconceivable to the engineers that designed the system. Those poor bastards might have been on the verge of figuring it all out when an appropriate control input triggered a warning.
Originally Posted by Originally Posted by roulishollandais
I liked very much your “air" combat with Iceman50
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Originally Posted by MachinBird
Roulishollandais, you may has mis-perceived this interchange.
Basically When Iceman50 stated he was a Naval Aviator, I knew
exactly what his training background was before his airline career,and
he knew mine.
It means that if you were flying hundreds of miles from your ship in lousy weather and your navigation system packs up followed by your communications and some of your critical systems, you can still fly his wing back to your ship or a divert field after you pass your HEFOE signals, even if he is a brand new Ensign.
He was saying that his Airbus is easy to fly (for him) which I believe fully. It also points at inappropriate fundamental ATPL training standards as an additional causative factor for AF447.
If I unvolontary have hurted your high sense of egality and your humility, I apologize .
To hope some pardon could I edit my post, replacing "air"combat by "Naval egality" or "Naval confidence" ?
At reading the some agressive Iceman50's post, I felt he was throwing you a curious challenge...
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Originally Posted by iceman50
Very condescending!
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Originally Posted by iceman50
Perhaps you could also grace us with your practical / hands on knowledge and experience of the flying the Airbus.
( An Airbus pilot TRE/IRE, + 20 years military- Rotary(piston/gas turbine) fixed wing (piston and fast jet),
6 years Boeing (757/767) and 16 years Airbus flying A340/A330).
And I felt equity, regularity, in your answer, asset on asset. Probably I was not alone to feel that .
You also showed us your surprise and your happiness to find a brother in arms, and brothers in very accurate, exigent and engaged flying.
I liked that from both of you.
Your description from coming back safely after nav and com systems failure in bad weather far away from your ship is very adequate in this forum about the AF447 LOC in the ocean, and full of rich humanity of our pilot community, Naval and not Naval, whose Home is in the sky...
Best regards, with regret to have been an "insider" in your interchange..
Last edited by roulishollandais; 25th Feb 2012 at 17:52.
Reason: bb code
So far, in all the discussions, I've not yet seen a mention of even a 'proposal for rule making' to replace the obsolete certification rules for pitot tubes.
Extract (pages 20-21) Furthermore, service experience indicates that flight crews have experienced temporary loss of or erroneous airspeed indications, malfunctioning and/or damage to temperature probes in severe icing conditions (in areas of deep convection). The main suspected cause is ice crystals in high concentration. The on-going investigation of an Airbus A330 accident 7
(flight AF447, 01 June 2009, Atlantic Ocean) has established in the interim report No 2 that several (twenty-four) maintenance messages were transmitted by the ACARS system and that these messages show an 7 Refer to the Interim Report No 2 dated 17 December 2009 available on the BEA France Website. Please use the following link: FLIGHT AF 447. inconsistency in the measured airspeeds. A meteorological analysis shows strong condensation towards AF447’s flight level probably associated with convection phenomena. The aircraft Pitot probes potentially may have encountered severe icing conditions including ice crystals and mixed phase. However, as of today the root cause of the accident has not been established, therefore it is not possible to determine whether or not the mentioned airspeed measurements inconsistencies have played a role among the causal factors.
I am as yet unable to locate my quote (sic) from the source that mentions the a/c did not immediately respond to Bonin's initial N/U command. As he took control, you will remember, he input Up elevator and RollLEFT ailerons.
It makes sense from the fbw protection philosophy, as the STALLSTALL just after a/p drop indicates an AoA approaching aerodynamic STALL.
I continue to hold to the uncommanded Pitch Up theory of cause, especially when the pilot's inputs appear to have been additive, should the a/c autoclimb theory prove out. If the aircraft was not responding to PF's initial NU, I consider that to be evidence of the corollary to "Uncommanded", ie: "Not Responding".
Wind` shear can easily account for sufficient immediate excursions in IAS of 100 knots and more, an immediate explanation of loss of autopilot and acquisition of both STALL and OverSpeed (in that order) protections, IMHO.
I do not agree with the "PIO" idea of Roll dynamic. The evidence points to a chronic (controls neutral) roll to the right. An obvious reason would be damage to controls, perhaps a partially unstowed spoiler; these were intially deployed, then retracted, by Bonin.
regards
Aside. A possible explanation of the lack of concern of the PF re: STALLSTALL would be the appearance (or not) of the STALL activation threshold on the speed tape. This cue is not visible after ADR is rejected, leading to the possibility that it was visible, showed an obvious reason for the STALL warn, and hence his lack of comment. It would have remained only if the ADR's were still in, showing that the a/c, at least at this point, remained in NORMALLAW. It would support an airspeed corrupted by wind shear instead of ICE, for all that may mean to Thales, in their defense. edit. pp29 of 3rd Interim report shows a graphic of steady PITCH @1 degree whilst PF is inputting his supposed "mayonnaise" climb.
It makes sense from the fbw protection philosophy, as the STALLSTALL just after a/p drop indicates an AoA approaching aerodynamic STALL.
It does not make sense from any philosophy. In any case the sidestick was pulled back before the first stall warning.
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I continue to hold to the uncommanded Pitch Up theory of cause, especially when the pilot's inputs appear to have been additive, should the a/c autoclimb theory prove out.
Nowhere does it appear to have been additive. The pitch behavior was consistent with sidestick movement.
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Wind shear can easily account for sufficient immediate excursions in IAS of 100 knots and more, an immediate explanation of loss of autopilot and acquisition of both STALL and OverSpeed (in that order) protections, IMHO.
The aircraft was in alternate law 1 second after the AP disconnected. There is no overspeed protection in alternate law.
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I do not agree with the "PIO" idea of Roll dynamic. The evidence points to a chronic (controls neutral) roll to the right. An obvious reason would be damage to controls, perhaps a partially unstowed spoiler; these were intially deployed, then retracted, by PF.
The spoilers/speedbrakes were not extended until 2 minutes after AP disconnection.
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Aside....
I cannot make heads or tails of this last paragraph, but suffice to say normal law ended when the AP disconnected.
When did you notice the loss of SPEED Data? The pilots noticed it by reference eleven seconds AFTER the Cavalry Charge, yes? (Robert: "Loss of speeds, Alternate Law)".
jcjeant, You obviously totally missed my point..... Aircraft and aircraft equipment are designed, certified and manufactured in accordance with airworthiness requirements. This also applies to pitot probes.
The unfortunate problem in this case is that the certification requirements date back to the stone age... Both the Thales and Goodrich probes met those ancient requirements, or they would never have been fitted on an aircraft, but the testing conditions no longer match the environment they are used in.
Quote:
Originally Posted by me
So far, in all the discussions, I've not yet seen a mention of even a 'proposal for rule making' to replace the obsolete certification rules for pitot tubes.
What I was saying is that, so far, I've not yet seen any reports of substantial research into the 'unusual' pitot icing leading to UAS events, or any 'proposals for rule making' based on such research.
Yelling: "design a better mousetrap" is a bit pointless, if you can't state what that 'better mousetrap' is supposed to achieve..... Ah.... it should be able to trap 'zombie wombats'. Fine, give me a spec describing the size and behaviour of those zombie wombats, and I'll try and design something that might work.....
The report of July 11, page 29 shows quite clearly that the AP (probably No2 (FO's side)) disengaged at 02:10:05. The FO's IAS is not recorded, but the ISIS shows a speed drop from 02:10:06 and the Capt's IAS shows a drop from 02:10:07. I assume the FO's IAS showed a speed drop at 02:10:05 which caused the AP to fail.
I suggest you disregard the "The pilots noticed it by reference eleven seconds AFTER the Cavalry Charge, yes?" red herring.
Loss of Autopilot does not drive an immediate degradation to Alternate Law, does it?
What caused the AP to disconnect also caused alternate law. When the ADR monitoring sequence began the AP disconnected as a consequence. The same process caused the switch to alternate law.
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I woud be interested in your patient reply, with explanations. My small child can say "NO" endlessly.
I have no interest in entertaining a small child.
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EG: Does the Autopilot not make use of the spoilers?
If required, which it was not. Deflection of the roll spoilers occurred after AP disconnection.
What I was saying is that, so far, I've not yet seen any reports of substantial research into the 'unusual' pitot icing leading to UAS events, or any 'proposals for rule making' based on such research.
I do not dispute But you find this lack of interest on the part of regulators and certification bodies as something satisfactory?
A thread about the conversation between/among the piots? All PF says at a/p loss is "I have the controls"?
Does this suggest the pilot also knew the Flight Law had degraded? No. My point is that the all important question is what he knew, and when. He makes no mention of the Plane's conversion to Alternate? No mention of the loss of AirData? Does he illuminate the type of Alternate? No. Does he believe he is still in Normal Law, and speeds are not unreliable? This all is first verbalized many seconds later. Red Herring?
Neither does he call for the book, and establish other than a mundane reversion to manual control.
This raises no questions amongst the illuminates here?
The salient point is not what has been discovered, it is of no meaning to the crew/pax. What is important is if he was flying without a basic set of start points, how could such a thing happen?
There is also, of course, the possibility that the ironclad conclusions of some are in an area that not even the BEA has ventured, nor will they.
The proposed EASA amendments (NPA 2011-03 ~ Appendix P) have been added in green, plus 3 UAS events are plotted.
EDIT :: Some additional background:-
A common characteristic in most Unreliable Air Speed (UAS) events was the proximity to deep convective/tropical storm cloud formations; hence the EASA NPA 2011-03 Appendix P proposal is primarily a "deep convective cloud" extension to the existing JAR intermittent maximum envelope. This hypothesis is based on the often rapid onset of UAS events, the lack of airframe icing, some observations of strong moisture on the windscreen (e.g., rain reported but suspected to be melting ice crystals), and the proximity to such cloud formations, is that the aircraft are likely encountering an area of high ice water content[1]. The observations of low or no reflectivity on the pilot’s radar are consistent with flight through ice particles, possibly concentrated at small sizes[2].
Refs:- (BEA Interim Report No.3 - p.77)
[1]The background noise changed rapidly around 2 h 09 min 46. This change in the background noise was identified as possibly being characteristic of the presence of ice crystals but did not give rise to any specific comments from the crew, the phenomenon being little known to pilots at the time.
[2]The conversations in the cockpit did not reveal any malfunction of the weather radar and indicate that the latter displayed a usable image.
