Posts about: "EFATO" [Posts: 14 Pages: 1]

To nip any talk of intersection take off (it’s been said a lot on social media) from someone on the ground that seems to know what they are talking about :



interestingly he also seems to have been around to witness the TO roll and is mentioning a possible EFATO:

aviationweek.com/aerospace/aircraft-propulsion/faa-boeing-787s-need-be-powered-every-120-days

aviation.stackexchange.com/questions/14494/in-what-circumstances-could-a-787-stay-powered-on-continuously-for-248-days

Loud bang heard by pax 11A suggests otherwise. (ie EFATO) but still\x85

Could It have been a compressor stall / flow reversal at the point of EEC shutdown? Loss of thrust on both engines?

The odds are slim but would the RAT deploy in such a scenario?

(or has the RAT deployment observation been debunked?)

I'm reading a lot of the comments, speculation is something we all like, but some things just do not add up, even with a RAT deployed

if they had dual engine failure around 50 feet where you raise the gear, how can they still find the energy to climb, since they would be at VR/V2 speed (not V2+20 at that altitude, what VNAV would command after take off, especially with a take off weight of around 205/210 tons, the 787 wings are amazing but not miracles

if they had a normal departure, why did they not raise the gear, they had a positive rate since they were climbing and the speed according to ADS-B was a constant. if they were single engine ! this would have saved them with this weight and weather, one of the first things you learn when EFATO with a 787, raise the gear, your climb performance increases dramatically

if they did an intersection departure with they're genex 64-70K engines, they would have had a take off limited weight of around 172 tons, I estimate that they were close to 205/210 tons, (max zfw of around 161 tons and around 45/50 tons of fuel) even full length would have been a stress for the engines, with the prevailing weather conditions, intersection take off can be ruled out, they would have never made it, full length is already difficult.

When we see the video, the airplane is still climbing / flying straight and level (not losing altitude), yet we hear what we think might be the RAT, I can't imagine that they had the kinetic energy to do this with no engines. if they had dual engine failure, they would have been a brick, Hot and High, no thrust, flaps 5, zero chance.

flickering of lights etc. seen by the survivor and the loud bang heard, I would not trust pax observations, because of the things they had to go through, also and I've said this before, if it was a loud bang, where is the smoke and fire in the engines, or in the video, its not audible

lets see what the report will say, but it it could be a lot to swallow for some

I'm reading a lot of the comments, speculation is something we all like, but some things just do not add up, even with a RAT deployed

if they had dual engine failure around 50 feet where you raise the gear, how can they still find the energy to climb, since they would be at VR/V2 speed (not V2+20 at that altitude, what VNAV would command after take off, especially with a take off weight of around 205/210 tons, the 787 wings are amazing but not miracles

if they had a normal departure, why did they not raise the gear, they had a positive rate since they were climbing and the speed according to ADS-B was a constant. if they were single engine ! this would have saved them with this weight and weather, one of the first things you learn when EFATO with a 787, raise the gear, your climb performance increases dramatically

Intersection take off can be ruled out:
if they did an intersection departure with they're genex 64-70K engines, they would have had a take off limited weight of around 172 tons, I estimate that they were close to 205/210 tons, (max zfw of around 161 tons and around 45/50 tons of fuel) even full length would have been a stress for the engines, with the prevailing weather conditions, they would have never made it, full length is already difficult.


When we see the video, the airplane is still climbing / flying straight and level (not losing altitude), yet we hear what we think might be the RAT, I can't imagine that they had the kinetic energy to do this with no engines. if they had dual engine failure, they would have been a brick, Hot and High, no thrust, flaps 5, zero chance.

flickering of lights etc. seen by the survivor and the loud bang heard, I would not trust pax observations, because of the things they had to go through, also and I've said this before, if it was a loud bang, where is the smoke and fire in the engines, or in the video, its not audible

lets see what the report will say, but it it could be a lot to swallow for some

Retired RAF avionics technician, PPL / Glider pilot with ~ 700 hrs. VC10 double EFATO survivor.

The TCMA system should be inhibited when Air / Ground logic is in Air mode.
I understand that it has Inputs from RadAlt, Weight on Wheels, etc.
This airframe was reported to have had a history of significant electrical / electronic problems, including on the prior inbound flight.
There may have been water ingress in the E&E bay, likely causing corrosion or other damage.
Chafed or damaged wiring / cable insulation within looms is possible. Including the landing gear microswitches.
The landing gear may have been interrupted in the cycle.
BOTH engines are reported to have shut down, so whatever happened is a system common to both engines.
TCMA failing at the moment of gear retraction appears to fit with the available evidence.

Presumed or reported? If the latter, by whom?
I do not intend to single you out, but I want to illustrate something with this response.

A lot of discussion on this thread has pointed toward two engines failing - or losing power - for a variety of reasons.
PPRuNe members are analysing and discussing this tragedy.
When a credible report comes out that says you, or we, can say that engines were shut down or failed.

Using unconfirmed news reports, social media, or PPruNe analysis as a basis of "fact" is hazardous.
A number of posters succumbed to this: see the obsession over white and green lights at the exit door (near seat 11A) as but one example.

As an aside: your EFATO story might be of interest on the Mil Av forum.

FADEC Power supply: The Safran FADEC used on the GEnx-1B here is most likely a Generation 3 FADEC. The same Generation as used for CFM56-5 and -7 in A320 etc. So with high probability the same overall topology with independent 3 Phase alternator supply for the FADEC is used because similar certification standards are required and nobody develops a FADEC from scratch if he has a proven and qualified one.
Detail form Airbus here: https://studylib.net/doc/27601211/51...british-cfm-56

Safran FADEC Gen 3 uses: https://www.safran-group.com/product...engine-control

- CFM56-5B de CFM International

- CFM56-7B de CFM International

- CF6-80C2L1F de General Electric

- CF6-80C2K1F de General Electric

- GE90-115B de General Electric

- GEnx-1B de General Electric

- GEnx-2B de General Electric

- GP7200 d’Engine Alliance

- TP400-D6 d’Europrop International.

So if there is a latent failure in the design or software of this FADEC generation which can lead to a dual EFATO most of the current airliners worldwide have to be grounded.

This is not true. The AAI could be at 50 feet and a pilot can set a suitable climb attitude and push the thrust levers forward to enter a “normal” climb. The flight director would be useless at this point as it is commanding the descent.
So no, the AAI does not need to be changed to commence a climb.

I completely agree. I imagine it relates to the ten minute max power limit on the live engine. Less and less relevant as the aircraft can give MCP easily. My current jet type does not have an engine failure memory item. I looked for a B787 EFATO memory item in the QRH but could not find one. Perhaps a current B787 pilot could confirm?

I don\x92t really know what you are talking about. I\x92m current 787 and have flown many types including airbus prior to this. EFATO is normally an SOP handling exercise, not a memory item in itself. Memory items on nearly all types cover the specific drill for the engine only in all regimes of flight\x85ie severe damage/separation, engine limit exceedance/surge, engine fire. ie you\x92d never say \x93I\x92ll take the memory items for an engine failure after takeoff\x94.

EFATO handling is similar on most types too\x85in essence, contain any yaw, rotate, get the gear up and either trim it out or (787) let the aircraft trim it out\x85.AP in and once safely climbing away at a defined altitude diagnose followed by memory items if applicable. 787 you don\x92t action any drills until above 400ft so it would be extremely unlikely this crew actually got the stage of touching a fuel control switch.

Some assumed numbers about normal biotreatment.
https://www.biobor.com/wp-content/up...ation-IATA.pdf

If we assume 50 tonnes fuel load a 100ppmw biotreatment will be 5kg of biocide total in all tanks.

The GEnx-1B will burn about 4,5kg/s fuel each on a take off run (give or take a bit) so 9kg/s in both donks for about 20s until rotate.

So the total nominal biocide dose could be pumped in about half a second through both engines on take off power if it where not mixed at all and arrives in both engines at the same time.

This gives you an idea that with the nominal amount of biocide dose not much could have happened. If biocide is the source of this dual EFATO than an extreme overdose in addition to wrong application preventing mixture with the fuel had to be the case.

This sounds convincing, but I have read the investigation report on Jetstar Airways serious incident (VHVKJ) with great attention, and if I understand it right, things may be a bit more subtle:

First, the problem involves the valves (notably but not exclusively FMV and FSV), not the combustion of the product:
Second, the doses apparently don't need to be that high to result in a problem. A x10 dose seems sufficient:
Third, the main cause of the incident seems to be associated with magnesium salts dissolving in water instead of fuel:
Fourth, and despite the report indicating that ( my bold ) "In this serious incident, it is highly probable that, when the Aircraft was descending for landing, there occurred oscillation in rpm of each engine causing both engines to temporarily fall below idle at separate times because Residue primarily composed of magnesium salts accumulated in spools impeded movement of spools that involved in fuel metering of both engines.", it should be noted that the reported "rpm oscillations" of left and right engines were close to each other in time:



These "rpm oscillations", leading to substantial loss of thrust, could as well have occurred simultaneously, and 81 seconds (for the RH engine) is an awfully long time. According to the report, Kathon FP1.5 is not used anymore for biocide treatment, but another contributor ( nachtmusak , who seems to be a petrol specialist) suggested that other products may have similar effects .

Therefore, regarding the case we are discussing at large (thanks again, mods!), I think we shouldn't overlook the hypothesis of fuel contamination by biocide, since it is a single point of failure (among a very limited number of SPoFs) from a system analysis point of view.

In the Gatwick take-off incident discussed above, 38 x the correct dosage of biocide was mixed in with the fuel. In the Japan descent case also discussed above it was probably 10 x the correct dose....[NB, I originally, and very incorrectly, said 100 x the dose, having mis-read the relevant paragraph). In the Gatwick case, the ground guys doing the dosage had never done it before, and were working from the manual. They did not understand what ppm (parts per million) meant and had to google it. They then miscalculated the dilution necessary.

Neither incident reports make for pretty reading. But, in neither case did they experience near-simultaneous engine failure (not far off that, but still assymetric).

I found descriptions on the systems of the 787 were easily discovered online, and while I have no hands-on experience of aircraft related matters, I do have experience in wider electrical theory and maintenance.

THRUST Asymmetry PROTECTION.
"For an engine-out condition, Thrust Asymmetry Protection (TAP) reduces thrust on the operating engine to ensure there is sufficient rudder for directional control. TAP reduces thrust when the airspeed decreases below approximately V2 on a takeoff or below approximately VREF on a go-around. Once speed is increased above V2/VREF, TAP increases thrust."

From what we know so far, it does seem the engines were not producing sufficient thrust, during a period when it would also be crucial to maintain electrical output for the electro-hydraulic systems and critical electrical loads.

Reduced electrical output could explain the failure of the gear to complete retraction, maybe caused by a generator failing at the worst possible moment.

If there was an EFATO, the ability of the remaining generators to provide sufficient power might become questionable, as is highlighted with the load shedding system.

Other features which are unique to the 787 could be contributing factors in explaining the accident.

It is known the 787 will generally employ an extended take-off roll, and a relatively higher V1 and Vr, and also climb out less steeply than other aircraft. Using more of the runway would reduce the margin for aborted take offs.

With the evident lack of thrust early in the climb out, and failure to retract the gear, if V2 had not been maintained, the TAP system would have reduced thrust even further. Manually increasing thrust will be inhibited.

None of the above makes any sense. There are excellent videos of the takeoff. The aircraft was rock solid in yaw. The takeoff roll and rotation appear normal. Had the flaps been up they would have had a tail strike before getting airborne. The videos show a normal takeoff roll, normal rotation and normal initial climb. At some point below 200 feet AGL all thrust is lost. Here is a video of what a single engine failure looks like before reaching acceleration height. Note also how the wing looks when it reaches about the same distance the Air India video is shot from. At flaps five they appear up.