Posts about: "FDR" [Posts: 113 Pages: 6]

The recordings are simply of too low quality to draw any conclusions from.

If it was dual engine failure shortly after rotation, that is very bad luck and I doubt any crew could recover from something like that.

I could speculate further but I think it\x92s just too hard to say without better quality footage or FDR data.

very bad luck, or a common root cause. It remains to be seen.

Reports say that one of the black boxes have been recovered and the search continues for the other one. Apparently the B787 flight recorders log voice as well as data so only one is suffice if not damaged.

AFAIK , there is no available source of TAS data for this event, at least until we see the FDR traces.

@FDR, you made a comment earlier re the gear sequencing. It appears that you were referring to the 787-9 (doors then tilt). The 787-8 is different, according to this post and this YT video:


In it, the -8 tilts the bogies then opens the doors.

Many thanks. It still is a concern that the tilt has occurred but no doors have opened.

Are you thinking of the EK A340 that departed with a 100 ton descepancy entered in the box resulting in incorrect thrust derate and under cooked V speeds? That aircraft was saved by the flight crew that fire walled the thrust leavers with about 600M remaining. Tail strike and destroyed the LOC antenta, but was able to get Airbourne then return for landing at YMML. Is this a possibility? 100 ton gross error, resulting in incorrect thrust, speeds and flap setting? Pilot mistakes lack of thrust for partial engine failure? The confusion and startle factor as the aircraft is rotating with a surprising lack of thrust and the runway end fast approaching may account for the gear not being selected up. If there were a gross error in the weight entered in the FMC, no takeoff config warning. 40 degrees C, flaps 5 instead of flaps 15 or similar? Hopefully some initial data from the FDR may be a pretty good indication.

Hard to imagine if that mistake was made he\x92d get on the radio saying engines losing power with out pushing levers up first ? What ever happened had guy in left seat stunned ? My opinion only , if he was a training Capt he , like most guys in the left keep a good watch on where hands go . If an incorrect weight, chances are he\x92d know on runway and thrust to TOGA , those engines appear to be along way off producing thrust . If flap was raised by mistake , flap can be lowered just as quick . He\x92d not be on radio saying thrust decreasing while looking at flap up . If miss set alt hold he\x92d be calling modes and selecting higher altitude and changing climb mode thinking he\x92s got to remember to write a report on arrival . If engines turned off deliberately!! Big If , no need for radio calls , turn engines back on and protect them and try isolating flight controls, if possible .

If RAT out ??? That tells a lot .

Not long to wait now ?

condolences to family\x92s and loved ones !

A summary of the more certain things we know about the accident so far:

The takeoff run was from the full length and appeared normal, even after comparing with the same flight on previous days. This very much reduces the likelihood of it being a performance issue, e.g. wrong flaps, derate, ZFW/TOW, etc.

Shortly after takeoff, the gear started retracting but stopped in an early intermediate position. At the same time the aircraft climb rate dropped off, then it started a shallow descent. This is consistent with a loss of electrical power causing a loss of hydraulic pressure and total engine thrust from both engines reducing below that generated by one engine at the takeoff setting. The position reporting also went offline at that moment, indicating that it was likely load shed due to an electrical malfunction. What exactly caused the engine/electrical issues remains speculative. An action slip mistaking flaps for gear seems much less likely as due to the above, the correct selection was probably made.

From the videos of the last moments, there is strong evidence that the RAT was deployed, which has a very short list of possible triggers. The sole eye witness from inside describes power issues which lends credence.

Taken together, it seems that there was an event (or events) shortly after rotation that compromised both engines and the electrical system. There is no evidence yet of birdstrikes and continued engine operation *should* not be affected by the aircraft electrical system as they are independently/internally powered, so logic would have the engines failing first leading to a cascade of other problems. Something that affects all engines pretty much simultaneously is a rare beast but it has happened in the past; outside of a deliberate selection of the fuel and/or fire switches for both power plants there is fuel contamination, FOD and not much else. Its seems at least one FDR has been recovered so depending on where they take it for read-out, we should get some initial facts fairly shortly.

This indeed is the best summary till now

Yes, we did acceleration checks, time to 100 knots, on the Valiant and, I believe, the Victor in the RAF. As well as brake drag, this proved engine performance was correct. I was surprised this was not done when I moved to civil jets. Many years ago I proposed a system called TOPIS. Take Off Performance Indicator System. Basically a bug driven around the ASI to show required and achieved speed.
IF, repeat IF, such a system was installed on that 787 it MIGHT have revealed a thrust problem before V1. ( and prevented the TUI BRS incident as well as EK at Melbourne)
So, after a lot of thought, an unexplained loss of thrust on BOTH engines must be in the frame. But why? What is common to BOTH except the autothrottle system, driving the thrust levers. Even then it is possible to manually firewall the thrust levers, at least one could on the 73,75, and 76.
So, a real mystery. I will await the Investigatirs conclusion now they have the FDR.

On my 787 we call 'thrust set' which must be achieved by 80kts. This is confirming the thrust achieved matches the target thrust at the very least although this assumes the target thrust is correct, of course.

Or he may have heard the RAT spooling up. Valuable as a witness account may be, we’ll have to wait for FDR and CVR data and/or wreckage analysis before drawing conclusions.

I am sure the FDR will be primary in determining the cause of this terrible accident. I will await the findings like we all should. In the meantime I sincerely hope it leads to far greater research into the the interaction between humans and the automatics in modern aircraft, specifically the reaction of auto throttle systems to false or misleading inputs into flight control panels. The Asiana 777 crash in SFO really got me going on this. Although this was in a landing scenario, it showed how lack of familiarity with the 777 FLCHG system compared to the Airbus and obvious fatigue, can cause grief. At its heart it was related to interaction between pilots and systems. My point is that MCP input errors such as incomplete or false inputs into altitude targets could and has led to early VNAV capture and subsequent inadvertent wind downs of power that can go unnoticed in high workload situations until it is almost too late. I have substantial time on 3 different Boeing types, but not the 787.

A preliminary report is supposed to be published within 30 days.

But I would fully expect some findings from the FDR and CVR analyses within the next few days, given the high profile of the accident and the fact that operators of 1000-odd 787s are waiting anxiously in case there turns out to be some previously undiscovered failure mode that could affect their fleets (though that's highly unlikely IMHO);

One has to assume the second blackbox will now just be used as a confirmation of data from the first one? In the 787 they're combined units (EAFRs to be precise, combining FDR and CVR) and effectively duplicated, with one at the front and one at the back.

Yes, the media (not only in the quoted article) are still having trouble with the concept that the 787 doesn't have a separate CVR and FDR.

Hi tumtiddle,
yes, I do read all the posts in any thread from the start and noted that it is basically just a dupe in this case, but many posters do not seem to do so and even just a little upthread (and also in lots on news media even currently) it has again been mentioned that only one was reported found, as if that would be a disavantage. Just wanted to add it to the thread clearly, for those of us who read all posts!

The status of the engines/hydraulics/electrics/RAT is likely to be one of the first findings when the FDR is read.

So get the arguments in quick as we'll probably know definitively within a couple of days.

Good point. In the survivor's narrative, the sequence is: 5-10s after takeoff -> plane seemed stuck in the air -> green & white light came on -> they "gave race for more takeoff" (revved up) -> entered straight into (hostel).