Posts about: "EAFR" [Posts: 87 Pages: 5]

787 gear and flaps/slats are both on the centre system, powered by 2x big electric pumps and no EDPs, so retraction should be minimally impacted by engine failure assuming electric power was still available and reconfiguration worked. Note the 787 has two generators per engine so generator failure is also unlikely to contribute, unless both engines failed taking out all four generators (and presumably no APU running).

From that thread, I believe it was discussed that on most/all other large transports, deploying the RAT re-powers the CVR/FDR. The 737 didn't have that happen because no RAT. You may still get a few second gap while the RAT deploys.

The 787 has 2x Enhanced Airborne Flight Recorders (EAFR), which each record both cockpit voice and flight data. I expect they are also fitted with the dedicated batteries that the Jeju was a year or two too early to require. Per the NTSB , the forward recorder has a 10-minute backup battery.

Hopefully flight data is not going to be an issue for this investigation.

The suggestion is that the buzzsaw/propeller sound is the RAT; it does sound a bit like an interference pattern, but you don't get the engine roar with it.

It's also maybe visible in a few stills (e.g. post 64).

Especially when the video is clearly taken on the ground, when you could easily expect source switching due to shutting down an engine for single-engine taxi, then switch to APU, then ground power.

IIRC the CVR battery (in this case EAFR battery) is required to power at least the cockpit area microphone, if not the pilots' mics.

Once the RAT deployed at least some data should have come back.

This has been discussed upthread and has happened before (on a 777 IIRC) but did not result in a crash.

It does not explain the RAT and generally you would expect crews to shove the thrust levers fully forward.

It looks like you recall correctly. This skybrary PDF document "Fade Free Memory" describes the EAFR

https://skybrary.aero/sites/default/...shelf/2955.pdf

I quote from it:
That seems to indicate that as long as the forward EAFR is powered, the datastream from the cockpit area microphone will be available to both EAFRs (assuming the network to the aft EAFR is available and working).

The whole document is worth reading to glean more details.

Indeed GE EAFRs have internal battery backup but it only server as a power source for locator beacon. The a/c might have been equipped with RIPS (an independent power supply for recorders) but for instance for 737 it's user selectable option, not sure how that relates to 787 - maybe they became part of standard equipment.

It's not surprising. The 787 was designed with a modern digital flight recorder (Enhanced Airborne Flight Recorder, EAFR). It does both - records data and voice. No more separation of CVR+FDR. Just one device.

But the 787 was equipped with two redundant recorders. One in the aft, one in the front compartment. Both record identical data. If one of them was found in usable condition, then they're good. It will already have all the data they need.

On item 1, the TCMA issue should have been fixed, it does fit the sort of issue that occurred here. TDRACER can talk to that, and has done in 2019 and again in post 792. As to flap auto retraction, the B787 like all Boeings has a gated flap lever, and the flaps are only able to move independent of the lever by flap load relief. That would not have caused a loss of thrust, and in this case it is evident that the event is a thrust loss not a CL loss.

On item 2, the video shows no asymmetry at any time, so there is only a symmetric failure of the engines possible. Back on a B747 classic, you could chop all 4 engines at the same time with one hand, on a B737, also, not so much on a B777 or B787. I would doubt that anyone used two hands to cut the fuel at screen height. Note, there was a B744 that lost one engine in cruise when a clip board fell off the coaming. Didn't happen twice, and it only happened to one engine.


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Neila83 is correct, the gear tilt pre retraction is rear wheels low, and at the commencement of the selection of the retraction cycle (generally), the first thing that happens is the inboard MLG doors start to open below the wheel well and then the bogie is driven to front wheels low. (There is also an option that the inboard gear doors start to open early as a result of WOW sensing to improve the SSL climb limit). [my bad, for the B788 Capt Bloggs informs us the gear door sequence is after the tilt, not before, the B789 has the before tilt, the option for the door open at rotate is separate]

The inboard doors do not appear to have opened in this case, yet, the gear is forward wheels down. This appears to be out of sequence. TD may have better knowledge on the options that exist with the B788, but this is not looking good at this time.

There is enough in the way of anomalies here to end up with regulatory action, and airlines themselves should/will be starting to pore over their systems and decide if they are comfortable with the airworthiness of the aircraft at this moment. A latent single point of failure is not a comfortable place to be. Inhibiting TCMA might be a good interim option, that system could have been negated by having the ATR ARM switches....(Both)... ARM deferred to the before takeoff checks. The EAFR recovery should result in action within the next 24-48 hours. Boeing needs to be getting their tiger teams warmed up, they can ill afford to have a latent system fault discovered that is not immediately responded to, and the general corporate response of "blame the pilots" is not likely to win any future orders.

I think we are about to have some really busy days for the OEM.


Not sure that Neila83 is that far off the mark at all.

Dont be afraid. I am following along. There is no evidence. Can you vouch for the authenticity of the audio recording? I cannot see a RAT in that image only a blur.

I tell you what I am watching closely, the words and subtle meaning in the press conference of Civil Aviation Minister, Shri Ram Mohan Naidu, who has set up a “special high level committee” to oversee the investigation of this “incident.

A little odd given they have the DGCA and AAIB in place, dont you think?

He indicates they are to report within three months.

It is now 48 hours since the EAFR was recovered. A small group of people know the answer NOW.

The better quality video does show something. It certainly could be the RAT. Automatic or manual deployment?
Assuming GE receive data from these engines in flight, a massive failure would prompt a swift communication from GE. Or a massive electrical issue could put Boeing on edge and also prompt urgent inspections on their aircraft.
Since here we are two days after the EAFR was found then either both the aircraft manufacturer and the engine manufacturer know they are off the hook. That can only be for one of two reasons. They know there was a maintenance issue with this aircraft ( no IFE and call buttons?) or they know it was a handling error.
Of course, tonight we may get urgent bulletins from Boeing or GE but the longer that does not happen, as Bloggs wisely stated, then we are left with a grim reality. Send in the clowns.

What pilot action is positively ruled in and what pilot action is positively ruled out at this stage?

From the comfort of my couch, I would contend that this crew have had a condition that was extraordinary (in the full meaning of the word) and have acted in a timely and correct manner. There is nothing in the flight path other than the fact the aircraft isn't at a gate in London that indicates otherwise. The fact the aircraft is not sitting in London does not have any characteristic event in the available information to conclude other than through the general assumption that pilots always cause problems, and having done nearly half a century in flight safety investigation in the military and airlines, I would contend that on balance flight crew save aircraft far more often than they cause losses. "It takes a computer to really stuff up something..."


Not at all, the system including the OEM and Regulator have duty of care obligations that they tend to take seriously, mores than the public gives them credit for normally. In this case, the investigators have data that will shortly be sufficient to determine the immediate actions that would be necessary to mitigate risks to the public. My own opinion is that action is shortly coming, it doesn't need the EAFR, and it will cause its own political fall out.

The B735 crash event was evident from the first access to the ADSB data. The kinematics told the story, which is usually the case. In this case, the flight path is sufficiently clear to be of concern. Specifically, this event from a human-in-the-loop is a binary outcome. There is zero grey areas in the involvement of the flight crew, and I contend that there is no reason to consider their actions as being anything other than exemplary. If the area mic shows otherwise, I will amend my position, but right now, I have greater concerns with the continued operation of the B787. This event is an either/or, a binary event, like Kev Sullivan's QF072, and I fear we are seeing a similar family of causation. Kev's a former squadron mate and friend from the airline, and the pax were fortunate to have him on board that day.

The untidy truth related to this event is that either causation will have ramifications to the industry for the foreseeable future; there is nothing trivial about this event from a systems viewpoint, apart from the devastating loss to every person concerned in the tragedy. Not than many accidents are so consequential in their impact, this will be one of those.

You answered your own question. The units would have had power. One pilot made a radio call so electrical power was available at the very least at emergency level.

It has been established that the B787 utilises a EAFR, a combined CVR and DFDR.

from the little I know:
* only the forward EAFR (Enhanced airborne flight recorder) has an (external) RIPS (Recorder independent power supply)
* and this RIPS provides, in addition to the forward EAFR, the cockpit area microphone and the preamplifier for this microphone with 10 minutes of backup power

Pretty recently, Indian media was reporting that the forward "CVR" has been recovered. Pure speculation..but one might interpret the use of this incorrect terminology and the continued search for this second 'black box' while the rear EAFR should have been easily recovered from the mostly intact tail-section, as an indication that things aren't going as well as expected regarding FDR/CVR data-extracting (as in rear EAFR lacking the last x crucial seconds, and forward EAFR now essential for recovery of the last x-seconds of area-CVR recordings, thanks to RIPS)

Because the EAFR has been out of the aircraft for three days now. A small group of people know what happened but perhaps not why.

If Boeing or GE had any inkling that their product killed around 270 people they would quickly order inspection of the offending item or system or quickly amend a procedure. The fact they have not done this is illuminating.

My information differs to yours, We do know the EAFR was recovered on Saturday. Are you suggesting that it sat in a room for three days?

Wow you seriously think a professional crew would shutdown an engine below 400 feet?
​​​​​​​Is there any yaw or rudder deflection in any videos?

My expectation is that at the very least the AAIB (India) would want to open / read in the presence of the AAIB (UK) and the manufacturer. They might even want to read it at a location with specialist equipment (NTSB in Washington, BEA in France, AAIB in UK). None of this would be unprecedented when looking at previous accident investigations particularly for those that took place in developing countries.

Quick example, EK 521 accident in DXB:

Pakistan A320 accident Karachi:

(1st June was 10 days after the accident).

As mentioned several times in this thread:

a) It might be damaged and they are going to need to use forensic techniques to recover the data. This can take time.
b) They could have read it out but due to lack of power to the rest of the aircraft and associated sensors at the time, it hasn\x92t recorded very much, like in the Jeju crash, so the investigation continues.

On item 1, the TCMA issue should have been fixed, it does fit the sort of issue that occurred here. TDRACER can talk to that, and has done in 2019 and again in post 792. As to flap auto retraction, the B787 like all Boeings has a gated flap lever, and the flaps are only able to move independent of the lever by flap load relief. That would not have caused a loss of thrust, and in this case it is evident that the event is a thrust loss not a CL loss.

On item 2, the video shows no asymmetry at any time, so there is only a symmetric failure of the engines possible. Back on a B747 classic, you could chop all 4 engines at the same time with one hand, on a B737, also, not so much on a B777 or B787. I would doubt that anyone used two hands to cut the fuel at screen height. Note, there was a B744 that lost one engine in cruise when a clip board fell off the coaming. Didn't happen twice, and it only happened to one engine.


​​​​​
Neila83 is correct, the gear tilt pre retraction is rear wheels low, and at the commencement of the selection of the retraction cycle (generally), the first thing that happens is the inboard MLG doors start to open below the wheel well and then the bogie is driven to front wheels low. (There is also an option that the inboard gear doors start to open early as a result of WOW sensing to improve the SSL climb limit). [my bad, for the B788 Capt Bloggs informs us the gear door sequence is after the tilt, not before, the B789 has the before tilt, the option for the door open at rotate is separate]

The inboard doors do not appear to have opened in this case, yet, the gear is forward wheels down. This appears to be out of sequence. TD may have better knowledge on the options that exist with the B788, but this is not looking good at this time.

There is enough in the way of anomalies here to end up with regulatory action, and airlines themselves should/will be starting to pore over their systems and decide if they are comfortable with the airworthiness of the aircraft at this moment. A latent single point of failure is not a comfortable place to be. Inhibiting TCMA might be a good interim option, that system could have been negated by having the ATR ARM switches....(Both)... ARM deferred to the before takeoff checks. The EAFR recovery should result in action within the next 24-48 hours. Boeing needs to be getting their tiger teams warmed up, they can ill afford to have a latent system fault discovered that is not immediately responded to, and the general corporate response of "blame the pilots" is not likely to win any future orders.

I think we are about to have some really busy days for the OEM.


Not sure that Neila83 is that far off the mark at all.

You answered your own question. The units would have had power. One pilot made a radio call so electrical power was available at the very least at emergency level.

It has been established that the B787 utilises a EAFR, a combined CVR and DFDR.

from the little I know:
* only the forward EAFR (Enhanced airborne flight recorder) has an (external) RIPS (Recorder independent power supply)
* and this RIPS provides, in addition to the forward EAFR, the cockpit area microphone and the preamplifier for this microphone with 10 minutes of backup power

Pretty recently, Indian media was reporting that the forward "CVR" has been recovered. Pure speculation..but one might interpret the use of this incorrect terminology and the continued search for this second 'black box' while the rear EAFR should have been easily recovered from the mostly intact tail-section, as an indication that things aren't going as well as expected regarding FDR/CVR data-extracting (as in rear EAFR lacking the last x crucial seconds, and forward EAFR now essential for recovery of the last x-seconds of area-CVR recordings, thanks to RIPS)

My information differs to yours, We do know the EAFR was recovered on Saturday. Are you suggesting that it sat in a room for three days?

Wow you seriously think a professional crew would shutdown an engine below 400 feet?
​​​​​​​Is there any yaw or rudder deflection in any videos?

if not on the rear EAFR, then all hope is on the forward EAFR being downloadable