AF447

[LeandroSecundo]

Hi,

C-checks. Does anyone know the frequency of C-checks?

+/- 18 months

Bye.

[takata]

@ LeandroSecundo
Check-C is every 3,000 flight hours. At A330/340 flying rate, it is flown in less than 9 months of commercial service.

S~
Olivier

[LeandroSecundo]

Hi,

Check C more:

SERVICE INFORMATION LETTER :

Bye.

[Peter H]

pitot tube inspection

HazelNuts39 The BEA Interim report mentions that the probes are inspected and cleaned at C-checks. Does anyone know the frequency of C-checks?

LeandroSecundo +/- 18 months

There is a big difference between checking the hole in an external pitot isn't blocked and a full check of the probe system. Is there a schedule for doing the former?

Performing a full probe check can require access to inaccessible places (see attached entry from the pitot tube thread). Leaving this to C-check time seems understandable.

Regards, Peter

(permalink) JRBarrett
I recently had a G-IV which had developed a serious in-flight data miscompare between the L/H and R/H air data computers. Ground testing quickly revealed a major leak in the static line feeding the #2 ADC.

We eventually found the leak to be caused by a cracked plastic B nut at the point where the static line feeding the #2 ADC connected to the R/H static port.

Fixing the actual problem took less than 30 minutes. Getting access to the point of failure however was another matter entirely. Six man-hours to remove the overhead ceiling panels in the entranceway to gain access to the tee fitting where the L/H and R/H static port lines joined together, (in order to isolate which side was leaking) - then an additional 35 man-hours of labor time to disassemble and remove the forward lav and galley, and then put it all back together afterward.

[funfly]

From this thread, one is bound to consider that the investigation has as yet not produced enough evidence to fixate on any initial cause.

However one is bound to consider two scenario's as most relevent (again from stuff on here, not the official report)

1. Ice blockage of all pitot tubes rendering the aircraft impossible to fly.
2. Aircraft entered a weather situation where it was unable to maintain flight. Pilot or Pitot?
1. is of course a technical fault, however the concensus here seems that failure of the pitot tubes could only be as a result of the aircraft being in bad weather.
Although this thread brings up some fascinating and very relevent technical information, it seems pretty obvious that the aircraft crashed because, for whatever reason, a decision was made to enter a weather system that it was not capable of dealing with - it's got to be as simple as that

[pax2908]

Not having access to the AMMs, so just a couple of questions here: flushing really means flushing of the whole pneumatic line all the way to the pressure sensor itself? So this procedure will necessarily call for a leak test, at the end?

[MROJunkie]

Interval

Hi,
intervals vary from airline to airline. As LeandroSecundo already stated for what is called simplified C-Check the interval is +/ - 18 month.

see below extract from a A330 maintenance requirement

Code:

CHECK       MAX. INTERVAL
MPC
PFC         Before each departure 
W           14 calendar days
A           800 FH since
C           1C = 18 months 
           2C = 36 months 
           4C = 72 months 
           8C = 144 months 
IV          1IV = 6Y = 72 month 
D           1D =12Y =120month

[DJ77]

So its not icing, but still the only known problem with these probes (as far as I know) is the drainage, and apparently its not easy to solve.

HN39,

It's not icing at the drain end of the Pitot but eventually, I think the front end ice up.

The following is a surmise entirely (I'm not an engineer) but it is the way I think things happen.

When drain flow can no longer evacuate all the incoming water, the tube starts filling. At this stage, total air pressure is still transmitted through liquid water with little error and possible instability. However, while the tube is filling up, the heat flow from the de-icing elements is modified by the increasing water volume and becomes gradually unable to efficiently deice the forward tip of the tube. When the tube is clogged, pressure falls rapidly through the drain at the rear and air speed indication follows. Since the liquid water is still heated it could start boiling close to the drain and cause intermittent overspeed alarms.

[rgbrock1]

I've noted some discussion of weather-related issues (turbulence) as being a possible initiator of AF447's loss. (please note the use of possible)
I do not, in any sense, wish to start a flame war concerning the topic of
climate change/global warming. (I prefer to call it global warning.)
However, and I'm sure those who are currently still flying would be able
to support, or refute this, perhaps AF447 is just the beginning of some rather
unpleasant nastiness brought on by the forces of nature, run amok.

In the back of my mind, anyway, I continue to wonder if AF447 entered a "freak" weather system which would have been "unsurvivable" by any aircraft ie, loss of control.
I know this is all conjecture on my part and I have seen no evidence of my
supposition. However, the images I have seen of the weather systems present at around the time of AF447's flight do show some degree of nastiness. But, perhaps, these images just don't tell the whole story. Would any satellite be able to show exactly what is contained in any weather system?

In essence what I'm thinking is that perhaps AF447 is just the beginning
of other weather-related phenomena heretofore unseen, and unexperienced, because of climate change-related issues?

I'm ready for the daggers now!

[BOAC]

No 'daggers', rgb, but remember several other a/c flew through the same ITCZ that night and came out the other side intact PLUS the sat weather pictures are colour enhanced. It appears to be have been a pretty 'standard' ITCZ by all accounts.

[funfly]

lomapaseo, I appreciate your comments and have ammended as you suggested.
Of course we won't know the 'official' verdict until the final report emerges - it's been said on here many times before.
However, this is a pilot's 'rumours and news' thread thread and a lot of the contributors are very knowledgable people (don't include me in this!)

[Hyperveloce]

Originally Posted by DJ77

Since the liquid water is still heated it could start boiling close to the drain and cause intermittent overspeed alarms.

thank you for that ! this is the kind of phenomenology I was looking for, to generate overestimated "airspeeds" and false overspeed alarms without any altitude change (and/or static ports failure). Now, does it mean that under this phenomenology, airspeeds should be underestimated in a first time and then possibly overestimated (bubbles overpressure build up) if it remains in icy conditions, before it recover its normal values ?
Jeff

[rgbrock1]

BOAC. I understand. But those other aircraft did not traverse the ITCZ
at exactly the same point in time and probably not in the same point
of space. Yes, the images I have seen appear to be "normal" for weather systems in the ITCZ. But, again, do these images tell the entire story? And, can they? (I'm thinking: heretofore unseen and extremely violent, updrafts and downdrafts buffeting the aircraft beyond design limits causing, at a minimum, loss of control. Something beyond the design limits of ANY aircraft.)
I know some of my supposition may appear to be "out there" but I truly do not think it is out of the realm of possiblity as to an initiator of AF447's loss.
Again, most of this supposition is based on my thoughts on climate change.
I believe it's real and I believe it's going to get worse. And I think that AF447 is just a sign. I hope I'm wrong.

[thermalsniffer]

Fortes Turbulances

No one has answered the question regarding the purported crew report of "fortes turbulances" (see posts 574 and 628 and underlying source material), and that it is not mentioned in the BEA report.

A second question is if the report by the crew did happen at 2:00, why would the A/THR be on at 2:10:46??

[Razoray]

I believe it's real and I believe it's going to get worse. And I think that AF447 is just a sign. I hope I'm wrong

Global Warming is real and it will effect areas already known for turbulent weather to produce even more severe conditions. The biggest issue would be the ocean temperture increasing, hence causing storms to intensify to levels we may never have seen before. The ocean temperture in the ITCZ was about 80f, I believe, which is very warm.

With Global Warming becoming a issue, traditional routes may need to alter to avoid these weather patterns. Just my opinion......

[mm43]

Will Fraser

In other words, isn't the straight course line speculation? If not, and it is accurate, it means the crew started diverting at the previous course report.

When I originally took a closer look at the BEA plot, I became aware when I blew the graphic up that the line drawn from the 0200z SATCOM position was not a continuation of the 028°T track to TASIL. As we all know now, the 02:10:34 position is actually 2.94NM left of track. We have no way of determining when this deviation took place, though one would suspect that it is related to events that commenced about a minute earlier - whether by design or as a result of is of course speculation.

I've prepared a graphic which shows the ETO times SALPU, ORARO and TASIL calculated from the 0150z ~ 0200z GS of 464KT. On passing SALPU the SBFN-SSR would have received the last squawk from AF447 - at about 254NM from the radar. The 0214z Ultimo Reporté and the now discredited 0214z ACARS position are also shown.

Somewhere in the Preliminary Report I remember seeing mention that the "Fortes Turbulence" report at 0200z didn't happen - seems it must have been media inspired.

A further update to the graphic is planned shortly which will show the circulation and likely wind shear encountered between a convective cell to the left of the track and the major cell the a/c apparently penetrated around 0209z with its center slightly to the right of track.

mm43

[BOAC]

Originally Posted by ts

No one has answered the question regarding the purported crew report

- I believe that posts here (certainly those I have seen in the last couple of weeks) state there is no indication that a report was actually made and the BEA interim does not mention any.

rgb - I don't think we need to worry about rogue cells in fronts at the moment. Yes the weather is going to change. Yes storms will be more intense. This front seemed pretty 'average' to me, and there is no reason (yet) to believe AF447 encountered any unusually strong turbulence. Maybe the FDR would show differently, but.................

ITCZs like this are crossed daily by 10's if not 100's of aircraft. Active cells are planned to be avoided. I remind you again that the 'colours' on the sat weather pictures are not an indication of what the weather radar would see. I believe they indicate cloud top temperatures?

[promani]

Impact Damage

Razoray, that would be the surface temperature of the sea, I believe.
I am another newbie to post on this thread, sorry, but I have followed it daily since June 2 with deep interest. I am quiet frustrated in the fact that the search for the FDR/CVR has so far been fruitless, and also the lack of information from the investigators.
I would like to ask you guys if any of you would have any idea what structural damage would have Af447 incurred upon impact with the ocean. As it is made of composite materials, would it have disintegrated into small pieces like a glass, or would it have broken into large segments? The reason for this question is for me to try to visualise the chances of the search finding the BBs. If they are still enclosed inside the tail section, then the chances of detection would be better, at least that is my inexperienced opinion. Thanks guys, and stay and fly safe.

[Hyperveloce]

Originally Posted by mm43

Will Fraser
I've prepared a graphic which shows the ETO times SALPU, ORARO and TASIL calculated from the 0150z ~ 0200z GS of 464KT. On passing SALPU the SBFN-SSR would have received the last squawk from AF447 - at about 254NM from the radar. The 0214z Ultimo Reporté and the now discredited 0214z ACARS position are also shown.

Strange, the speed between ORARO and the last known position at 02:10Z is much lower than between the other markers ! (435 kts versus 470 kts ?!).
Jeff

[BJ-ENG]

French Submarines To Resume Search For Brazil Flight Boxes

Bourse - French Submarines To Resume Search For Brazil Flight Boxes

Quote: "Starting next week, French submarines will attempt to track down the devices, in a second search phase lasting around a month, said a statement from the French bureau leading the crash investigation, the BEA."


I wonder why only a month?

In Johan Strumpfer's account of the search for the SA 747 in 1987, it was estimated that the total area of search would have stretched in excess of 800 square kilometres, an area that would have required in excess of six months. Ocean depth was in places over 5 km deep and very mountainous.