|
The aircraft is not in the area we looked in and so, she continued flying for far longer than we are expecting. |
@CONF iture
We don't know where the VS separated. |
But we know where it was found a few days later, don't we ?
|
The aircraft is not in the area we looked in and so, she continued flying for far longer than we are expecting. But why weren't any indications of parts of her found (as far as we know at this time), during the last search go-round? I think they were simply looking in the wrong areas. I understand the drift analyses (thanks to mm43 and the others who have made these understandable), what I really don't understand is why they used them to determine the recent search area. *Some* parts of the airframe had to go straight down (or as straight down as possible in whatever conditions prevail out there). It would be nice if they could find, say, the engines or a couple of robust structural pieces in order to more closely pinpoint the actual impact location -- and then work from there -- the FDR and CVR might be closer than they think. I guess that's why I mentioned using ROVs similar to the ones currently being used in the Gulf a couple of weeks ago. JD-EE and auv-ee had a nice discussion of their capabilities and provided a couple of links to similar kit. And yeah, it looks doable, slow, but doable. |
@CONF iture
We also know, that this was the scene of a monster storm system. For example, who is to say that the VS and other pieces of debris were not sucked up by waterspouts and deposited at the site where they were discovered a few days later. But the main argument has to be that a well-funded well-equipped year-long search operation came up with no evidence of the aircraft's presence (debris, signals from the pingers, etc.,) beyond what was discovered in the immediate aftermath of the event. |
CogSim
Personally I think it unlikely that waterspouts redistributed debris. BEA have determined satisfactorily (to them) that the a/c was intact at impact. This rules out what might have resulted (and has, in many unfortunate encounters) vis a vis in-flight loss of parts. A large a/c in upset and rapid descent would ordinarily be vulnerable to such disintegration; throw in large hail, massive updraft and 'blended' shear, it might have resulted in a shower of small bits and pieces. For instance, golf ball hail lifted at fifty knots against an airframe descending at two hundred would have been the same as flying through plum size gravel, yet there is no evidence on recovered materials of such an event. I have seen resin/fiber radomes after separation at altitude, the deformation resembles what we see here, with 447. The fractures of 447's radome resemble those seen in "flattening" (airstream) impact in other events. As much room as there is in this accident for "outlier" theories, whatever happened most likely occurred in pedestrian fashion; this does not prevent gaining knowledge in a general way that is helpful in making safer the future of air travel. It is human nature to "want" a certain explanation, whether it is "Lightning", "Weather", or "Fluke". No one wants to admit to simple (and preventable) cause. tailwinds, bear |
Monster Storm System
We also know, that this was the scene of a monster storm system. |
jimbeetle, the Brazilian air force's search grid on the first day of searching overflew the last known position, and they could not have been that blind to have missed the debris field, fuel or hydraulic sheen, etc. If they felt the scan of the area searched that first day was obscured because of visibility, I am quite certain that grid would have been immediately repeated.
|
It does not necessarily need to be a thunderstorm.
Mother Nature can be a bitch! Some years ago I was on the mid north coast of NSW driving south on one of those days you are glad not to be on a golf course. Scattered cloud at around 5,000 ft.intermittent rain and cold, I saw two cloud formations converging on each other, and as a gliding man stopped to watch. It was truly amazing when the two formations collided, the result was an instantaneous downward flow of cloud, not unlike a waterfall. The speed was astonishing, and so was the damage. About two miles further down the Pacific Highway, a swathe had been cut about 200 yards wide. An uprooted, very old fig tree a few cows, power lines and general bush had been demolished. I truly hate to think what could have happened to any aircraft hitting such a system. |
Excuse me if I missed it, but is any search being conducted now, or, when will it resume. Perhaps I missed the info if posted. Thanks
ww |
Originally Posted by smilin ed
"NEVER FLY THROUGH A THUNDERSTORM!"
regards, HN39 |
Originally posted by HN39 ... There is no evidence to suggest that any particular cell was exceptionally violent. Originally posted by wes wall ... .... is any search being conducted now, or, when will it resume. mm43 |
http://i65.servimg.com/u/f65/11/75/17/84/af447_11.gif
http://i65.servimg.com/u/f65/11/75/17/84/af447_12.gif It is all very good to put forward those representations about AF447, but then you have to do the same about LH and IB. Look at the scale at the bottom of the second graphic and draw your own conclusion. LH was 10 miles west of the airway, IB was 30 east. |
Pitch, power and AoA
EDIT:: This post contained a link to a faulty graph and has been withdrawn. I apologize for any inconvenience.
HN39 |
Hazelnuts
There is no evidence to suggest that any particular cell was exceptionally violent. As I understand thunderstorms, the greater the vertical development, the greater the energy, and thus "violence" in a storm system or cell. I got to investigate a ground mishap some years ago that resulted from a fast moving cell delivering a microburst that pushed a parked ground services truck (no, it wasn't chocked) into a couple of aircraft, causing no small amount of damage. It is common to get thunderstorms in Texas. We get SIGMETS regularly. There are violent thunderstorms a plenty here. I'll defer to a professional meteorologist here, but there seems to be a correlation between violent thunderstorms, in comparative cases. Those displaying tops upwards of 50K tend to be associated with greater voilence than less well developed (vertically) cells or lines. About three weeks ago, in Southern Texas, a storm system generated localized hurricane force winds that knocked off some roofs, kicked over trees, and did various amounts of damage. Is that not violent? Is it exceptionally violent? Would you have wanted to be flying through the top of that? |
CONFiture,
The meteorology is dynamic, and I don't believe I've seen a mapping of the atmospheric conditions existing at the time that LH and IB were on the track post ORARO. Flight LH507 (B747-400) preceded flight AF447 by about twenty minutes at FL350. The crew reported that it flew at the upper limit of the cloud layer and then in the clouds in the region of ORARO. In this zone they saw green echoes on the radar on their path, which they avoided by changing their route by about ten nautical miles to the west. While flying through this zone, which took about fifteen minutes, they felt moderate turbulence and did not observe any lightning. They lowered their speed to the speed recommended in turbulent zones. They saw bright St Elmo’s fire on the windshield on the left-hand side. The crew listened into the 121.5 MHz frequency throughout the flight without hearing any message from AF447. .... Flight IB6024 (Airbus A340) passed at the level of the ORARO waypoint at FL370 approximately twelve minutes after AF447. The crew saw AF447 take off while taxiing at Rio de Janeiro. When passing the INTOL waypoint, they encountered conditions typical of the inter-tropical convergence zone. These conditions were particularly severe 70 NM to 30 NM before the TASIL waypoint. They moved away from the route by about 30 NM to the east to avoid cumulonimbus formations with a significant vertical development, and then returned to the airway in clear skies close to the TASIL waypoint. .... Flight AF459 (Airbus A330-203) passed at the level of the ORARO waypoint approximately 37 minutes after l’AF447. The sky was clear but the half-moon, visible to the aft left of the aircraft, did not make it possible to see the contour of the cloud mass distinctly. After flying through a turbulent zone in the head of a cumulus congestus formation at the level of NATAL, without having detected this zone on the radar, he selected gain in MAX mode. At about 2 h 00, he observed a first echo that differed significantly depending on whether the radar’s gain was in CAL or MAX mode. The TILT was set between -1° and 1.5°. He decided to take evasive action to the west, which resulted in a deviation of 20 NM to the left of the route. During this evasive action, a vast squall line with an estimated length of 150 NM appeared on the screen, which was set to a scale of 160 NM. The echoes were yellow and red when the radar was set with gain on the MAX position and green and yellow when the gain was on the CAL position. No lightning was observed. ATLANTICO control, informed by the crew of their decision to avoid this squall line by taking evasive action to the east, asked them to return to the airway as soon as they could. This evasive action meant the aircraft flew between 70 and 80 NM to the right of the planned route. In addition, the crew was authorised to climb from FL350 to FL370. |
pich & thrust procedure, flight enveloppe
HN39, thank you for your simplified computation. I am surprised that the Mach number can decrease so close to M0.60 (with CLB thrust), which is close to the lower boundary of the flight enveloppe as far as I can remember (in such a configuration ~M0.58). Given that this latter can be further increased above M0.60 by a turn or turbulence, what if the AF 447 lost its flight control/protections (low speed protection, turn coordination, etc...) during a late (if the red areas appeared lately on the weather radar like in some past cases) manoeuver/turn to avoid the closest high top Cb cell (3NM deviation to the west of the normal trajectory) and with possibly increasing turbulences ?
(the stall alarms of the Air Caraïbe flight occurred around 4.3° of AoA I think) Back to the past cases analysed by the BEA in the 2nd interim report, does the BEA suggest that the pich & thrust procedure was rarely applied (thrust remaining locked and no pich setting to 5°) ? Jeff |
Pitch & thrust
Hyperveloce;
EDIT:: I regret that the first graph was faulty. I'll replace it by a correct version when ready.
Originally Posted by hyperveloce
does the BEA suggest that the pitch & thrust procedure was rarely applied?
For the cases studied, the recording of the flight parameters and the crew testimony do not suggest application of the memory items(13) in the unreliable airspeed procedure: |
Saturn V:
If the crew of AF447 reverted to SELCAL mode (and perhaps even switched to the DAKAR frequency) at 1 h 35 min, they probably missed any communication that may have occurred between ATLANTICO and LH507 on its deviation. Transcripts of communications between ATLANTICO and the LH and IB flights have not been released, nor is there mention in the interim report of whether AF459 was alert to communications between ATLANTICO and IB6024, flying about 25 minutes ahead of them. For the cases studied, the recording of the flight parameters and the crew testimony do not suggest application of the memory items(13) in the unreliable airspeed procedure IMHO, the attitude to be set up in case of unreliable airspeed at high altitudes should be, in fact, 2.5º (not 5º). Although QRH Memory items are (for the A330): - Below THRUST REDUCTION ALT 15º; - Above TR ALT and Below FL100 10º - Above FL100, 5º. this numbers are to be used at lower altitudes or close to the terrain. If AF447 pilots have used that attitude by memory, and specially if they kept a low power set up, that must have contributed to enter the Stall. We know by experience that, the use of 5º is (in most cases) beyond available power, especially when flying in the “coffin corner”, as most pilots do. What we actually do in my company, is to record every hour our actual attitude (and check that stand-by att (or ISIS) is not precessing) together with actual N1. We do know by heart that our average attitude should be around 2,5º up. If one finds himself in the middle of a storm in UAI situation, why then force the envelope with a 5º (ATT) climb, risking to stall the aircraft?:sad: |
SaturnV,
jimbeetle, the Brazilian air force's search grid on the first day of searching overflew the last known position, and they could not have been that blind to have missed the debris field, fuel or hydraulic sheen, etc. If they felt the scan of the area searched that first day was obscured because of visibility, I am quite certain that grid would have been immediately repeated. Since this was part of the initial search, my *assumption* is that the "search zone" was someplace, somehow, somewhere close to the LKP. We've all seen these pictures before, but slides 5 through 10 of Status of sea search operations as of 17 June 2009 show a very defined drift of debris and bodies from "somewhere" near the LKP (whether LKP itself or off to the West or Southwest as some folks surmise). Initial recoveries on 6 June were about 50 km north of LKP; on 7 June many recoveries were in the same area as on the 6th, with more from the NW, with one just about 10 km NW of LKP. Anyway, all that is basically an aside to my main point -- not everything floats -- some hunks of the airframe are somewhere close to where AF447 impacted. And my assumption is that is somewhere not far from the LKP. I guess I still can't wrap my mind around the BEA assumption that the FDR can CVR would drift so far. Sorry about the wishy-washy language, but everything about 447 so far is surmise and assumption. Plus it's the usual CYA from an old intel analyst. |
Saturn and Lonewolf50.. I agree,that was my point too..:ok:
|
butterfly:
If you get a chance, read the weather analysis at Tim Vasquez site, in detail. If you have already, sorry, I am late to the party on that bit of insight. |
Originally Posted by SaturnV
The meteorology is dynamic, and I don't believe I've seen a mapping of the atmospheric conditions existing at the time that LH and IB were on the track post ORARO.
As we can see, the system was pretty similar for LH, AF447 and IB. Now, I could also take the liberty to place a 55000 feet CB for any of those flights. The meteorology is dynamic and that's why a deviation 10 miles to the left can be only 3 miles 20 minutes later or 30 miles to the right another further 12 minutes. http://i65.servimg.com/u/f65/11/75/17/84/af447_13.gif http://i65.servimg.com/u/f65/11/75/17/84/af447_15.gif http://i65.servimg.com/u/f65/11/75/17/84/af447_17.gif http://i65.servimg.com/u/f65/11/75/17/84/af447_19.gif |
jimbeetle
June 1 search grids http://i136.photobucket.com/albums/q.../SNAG-0292.jpg I believe mm43 said the westernmost grid boundary on the wider box was 10 NM to the left of the track. June 2 (includes the boxes flown on June 1) http://i136.photobucket.com/albums/q.../SNAG-0290.jpg Unfortunately, the debris noted on the chart was not from AF447, and the Brazilian optimism was unfounded. June 6 http://i136.photobucket.com/albums/q.../SNAG-0298.jpg June 6 recovery of first debris and bodies. (square at the bottom is the last reported position) http://i136.photobucket.com/albums/q.../SNAG-0288.jpg Cumulative search grids June 1-5 http://i136.photobucket.com/albums/q.../SNAG-0297.jpg Disregard the circle centered on the last reported position. __________________ CONFiture, thanks for the images. |
Originally Posted by jimbeetle
Anyway, all that is basically an aside to my main point -- not everything floats -- some hunks of the airframe are somewhere close to where AF447 impacted. And my assumption is that is somewhere not far from the LKP. I guess I still can't wrap my mind around the BEA assumption that the FDR can CVR would drift so far.
From what I have learned in this thread, the point of impact is believed by BEA to be somewhere inside of a 40nm radius of LKP, because the position reports were transmitted at 4min intervals and 40nm represents the distance that the a/c could cover in 4min at cruise speed. The area north and west of LKP has been searched most thoroughly exactly because that is the area where the point of impact was calculated to be, based on backtracking the drift of the floating debris. The drift models are based on the available wind and current data, and assumptions about the exposure to air and to water of the various bits of debris. This approach is based on BEA's belief (from examination of recovered wreckage) that the a/c impacted the water intact, and thus all debris drifted from a single point. The goal of the search is to locate the large parts that sank quickly (mostly in place under the point of impact), and then to fan out from that point to find individual items. So far, no debris has been identified on the bottom, so the working assumption must now be that the point of impact is not in the area already searched. Because the area directly under LKP has not been thoroughly searched, the possibility that the a/c is under LKP has not been eliminated. |
Originally posted by auv-ee ... ... the point of impact is believed by BEA to be somewhere inside of a 40nm radius of LKP, because the position reports were transmitted at 4min intervals and 40nm represents the distance that the a/c could cover in 4min at cruise speed. " ... because the ACARS reports were transmitted at 1min intervals and 40nm represents the distance that the a/c could cover in 5min at cruise speed." mm43 |
Originally Posted by mm43
I think you meant to say,
" ... because the ACARS reports were transmitted at 1min intervals and 40nm represents the distance that the a/c could cover in 5min at cruise speed." Reviewing post 1178 by GreatBear (http://www.pprune.org/5715414-post1178.html), assuming that analysis is largely correct, I see that the ACARS position reports come every 10 minutes, and the reason for the 40nm circle is that ACARS fault messages started soon after the 0210 LKP report, and ended 4-5min later, when they would have continued had the a/c not ended flight. Is that about right, or am I still missing something important? |
While on the subject of being charitable, there has also been an assumption made that the a/c ground speed was less than 478KTS, whereas there is a possibility that a prolonged over-speed event took place and the manner in which the a/c impacted with the sea was as a result of a deep stall induced during a recovery attempt.
I doubt the over-speed part of the above, and believe that we should be looking very closely at any of the area within the 40NM radius that has not been visited by TPL's, the REMUS AUV's and the ORION side-scan sonar (SSS). More particularly those areas that didn't receive an initial aerial search. Also, the SNA "Emeraude" doesn't appear to have had her sonar operating at maximum efficiency in the period up to 30 June 2009, and those areas covered by her in that period deserve a closer look if they haven't been subsequently covered by other means. Without being privy to the [classified] operating depth of the "Emeraude", its not really possible to be much more charitable with regard to her efforts. mm43 |
I'd like a little assistance in ACARS reporting criteria. A while back I mentioned an old post regarding the normal law protection mode having the potential to cause a pitch up into a stall upon bogus sensing an approaching violation of the Vmo/Mmo limit airspeeds. If at time ~0208-0209Z before the primary string of ACARS events, the aircraft simultaneously filled all 3 pitot tubes with water or ice from one of the Cb cells it encountered thus plugging all bleed ports in the pitot tubes and then flew into colder ice that plugged the pitot inlets, it would then be possible to pressurize all 3 pitot systems in a fairly synchronous manner from water vapor pressure in the presence of pitot heat.
Would such an event (an apparently valid overspeed indication) show on the ACARS reporting? The original post by PILOTAYDIN indicated that there were no ECAM messages in the simulator session he participated in. I believe CONFiture earlier indicated that such a pitch up would require ace level systems knowledge to halt before it caused a stall. If ACARS would tattle on activation of the Vmo/Mmo protections then we can pretty well eliminate a Vmo/Mmo protection induced pitchup prior to the current known ACARS events. It would be useful to conclusively eliminate such a scenario since otherwise AF447 could be already on its way down in a deep stall at LKP and this would change the search strategy. |
OK Machinbird, it's time I do a little learning.
You have a flight control computer monitoring the instruments. How often does it scan them? If it's not too obsolete a design scanning instruments 10 times a second should be quite easy and any "buzz" that might introduce to control operation would be damped by the mass of the aircraft. They might even manage as many as 100 scans a second. But 10 is a reasonable sounding, to me, bottom end. Am I in the ballpark with this swag? (Scientific Wild A** Guess) If it is, that means all three probes would have had to plug up synchronously within a fraction of a 100 ms or less scan interval. That means a virtually instantaneous transition from open bore to plugged for all three probes within the same scan. I'm untutored here; but, two things stand out here as just a little fantastic for my engineering tastes. Going from open to clogged that fast without literally dunking it in a fluid of some sort bothers me as a concept, especially at an altitude testimony here suggests makes the Sahara Desert look like the Riviera except possibly for very small super cold ice crystals. The plane would have had to fly into a front of just the right shape of a density that would have severely shaken even the loaded mass of AF447 pretty badly. And it must have had just the right shape to turn the trick. Alternatively, and possible even harder to imagine, we would have all three probes progressing over say several seconds in such perfect synchronism to escape being noticed in the 10 times per second or faster scans. Based on my supposition of the computer's scan rate the three simultaneously clogged probes scenarios beggar my imagination. And the thought that the pilots would not notice it happening with the sudden penetration of a very thick layer of moisture in some form blotting out the stars "does not compute." They'd have had to be comatose or something. |
CONFiture
The left track is believed to be the LH flight. The BEA has not identified it, only to say the plane was AMDAR equipped. The FL is 325 In the interim report, the FL for the LH flight is not given. No indication of which flight is the track on the right. http://i136.photobucket.com/albums/q.../SNAG-0438.jpg |
Hi JD-EE. I think you have overcomplicated the situation a bit. There are smoothing functions after the initial reading of the sensors. The data from the 3 airspeed channels are compared for consistency and must be within X knots of each other to be considered acceptable. The 3 channels are then averaged in some manner and that number is used as the airspeed. If any channel is out of the acceptability window of x knots for y seconds, then it is rejected and the remaining two channels are used as the basis for airspeed. If those remaining two channels then fail a consistency check, that is when all heck breaks loose.
The system is going to hang together for a little while before data inputs begin to get rejected (at least y seconds). I'll have to dig out the reference for airspeed data processing again and post it. |
Is this new or old information about Airbus loss of airspeed emergency procedures??
Air France Crash Investigator Examines Airbus Emergency Drill - BusinessWeek There seems to be a disagreement among the parties about something fundamental. |
SaturnV,
The references are in the Interim Report #1 on page 65, and I think you did quote them yourself earlier.
The job of the BEA is to analyze all of the available information, not to keep some under the bed. But that idea of the monster CB in which the AF447 crew flew blind fully could be too convenient. I want to hear more on those Pitot tubes and how all the Pitot events have been dealt with at the company level, the manufacturer level, the regulatory authority level ? JD-EE, Three probes can block at a similar rate, it very unlikely, but it is not impossible, enough that the Manuals and Procedures talk about it. How many times did we hear during the pre departure briefing : "In the very unlikely event of a depressurization or a ditching ..." |
In the Business Week article, the Air France pilot who was quoted clearly implied that the response to loss of airspeed signal is to fly the aircraft without changing pitch. Does he mean that the pilot ought to override the autopilot, or simply to trim, or retrim, a particular nose pitch/attitude?
|
Analog And Digiltal Data
JD-EE and others
Permit an old software designer to make some comments. For your knowledge I am no pilot, the closest I have come is by designing and debugging software for high altitude rockets at Esrange. Those programs were only running once and for a short time - any problem and the rocket would self-destruct. Air data (pressute, temperature, etc) in the A330 are measured as close to the ports as possible and immediately digitized (some types of very accurate probes even present their value initially as a number). From the schematics available for the A330, this primary air-data handling is done by the ADM-units - one for each probe. The ADM-units are connected to the ADIRU-units by signal cabling. On these cables data are requested and/or transmitted in digital form using a standard protocol. The use of a common bus reduces the amount of wiring needed. The tranfer of data can usually operate in three ways: Clocked mode: A central system clock triggers data transfer at given times between the various units via the common data bus. Each unit then has its own time window for communication Polled mode: A unit higher in the system polls a unit lower in the system. The lower ranked unit then responds with either a "no data" answer or sends the requested data. Thus the higher unit controls the use of the common bus. Interrupt mode: A lower unit can send a "data available" signal on a dedicated interrupt line to request attention. Also in this case the higer unit controls the use of the bus. However, I don't think this mode is used on large aircraft because of the extra wiring needed to carry unique interrupt information to and from all units and the rather slow variation in measured data probably doesn't require interrupt mode. In none of these cases is any higher ranked computer "scanning" analog signals. However, such scanning may occur in some simple on/off cases, e.g. the postion of various switches. This will need additional wiring, As far as I have understood, the A330 systems don't operate in a clocked mode. This makes debugging of software much more difficult than in a clocked system. An old proverb states that "given the right data all computer systems will give the wrong result". Regardless of all testing and verification, some strange bugs may still hide in the code. There is at least one published example of this kind of bug found hidden in several versions of code used in an ADIRU unit during a long time. Regards |
emergency manoeuver/UAS memory items
Hi Auv-ee, Aguadalte and HN39
This emergency manoeuver (5°/CLB) of the UAS procedures mentioned in Business Week is the one suppressed at cruise altitude by Air France 5 days after the AF447 crash. It is in line with HN39 computations (Mach number decreasing close to the lower boundary of the A330 flight envelope at high altitude), and with the contribution of Aguadalte. But the crew involved in the BBC simulation successfully managed the UAS applying this memory item (5°/85% in the BBC simulation, to compare to the pitch/thrust tables in the QRH: 3.5°/78.9% if I remember correctly). The 2nd interim report states that this memory item has not really been implemented in the past UAS events (all planes remained in their flight envelope, even when they decided to initiate a descent when the stall alarms sounded): the AF447 may have been the first known aircraft to apply this memory item with the fatal consequences we know ? Jeff |
Hyperveloce:
Although we are only guessing, yes, I think it is possible that, that AI emergency procedure (if followed) may have contributed, especially in a turbulent environment, to a low speed stall at high altitude, in the AF447 case. |
..but what bothers me still, is that I don't see any reference to the 2:13:14 ACARS message in the last BEA interim report:
.1/FLR/FR0906010211 34123406IR2 1,EFCS1X,IR1,IR3,,,,ADIRU2 (1FP2),HARD Why don't we see an explanation for this message in the last interim, as it was done for other messages (from page 35 to page 41 in the report)? |
There is a significant mis-understanding occurring here regarding the UAS QRH drill.
Someone here has already hinted at the problem - the UAS drill caters to failure of airspeed information at low altitudes, (as a result of the Birgenair and Aeroperu B757 accidents). The inital pitch attitude of 5deg, under the configuration anticipated, is reasonable. The memorized portion of the UAS QRH drill does NOT require a "5deg" pitch attitude above MSA or circuit altitude. The last memorized item at the bottom of the drill states: "When at, or above MSA or Circuit Altitude: Level off for troubleshooting." The read-and-do section of the QRH drill then states: – GPS ALTITUDE ............................................................ .........Display on MCDU To level off for troubleshooting: –A/THR ............................................................ ......................OFF–AP/FD ............................................................ ......................OFF Then the drill requires an assessment of configuration for which it provides pitch and power settings: http://i277.photobucket.com/albums/k...24_11465-1.jpg NOTE that between FL 200 and FL360, the Speed is 260kts and the required Pitch and Power are stated as "3.5deg/71.9%N1". Assuming appropriate training and airmanship, I cannot imagine that an experienced crew would, at FL350, slavishly pitch the aircraft up to 5deg upon loss of airspeed information. They would, I expect, instinctively know what would happen if they did this, and changed what was working well, (in terms of pitch and power) moments before the loss of airspeed information. Although Bloomberg/Businessweek reported it, the original story leaves out important details regarding this drill and speculates without either understanding the drill and the airplane or knowing all the facts, which remain locked in the DFDR and CVR. PJ2 |
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