TOGA vs firewall
 

I fly 330's. Toga is throttles full forward, with max thrust still controlled by fadec's, and is not above max "rated" thrust.

In DC10 and 737's that I flew previosly, Go Around thrust was a setting slightly below throttles full forward, and at a position appropriate for max "rated" thrust. If I pushed the throttles all the way forward, i.e. firewall (which used to be a proper SOP term in some airlines), I would use max available thrust, which would possibly be above max rated thrust. This could lead to a complete failure of the engine/s if unlucky, and most surely would lead to some damage or life-time degradation, but could be used in a situation where the only other alternative was ground impact.

Is this not the case in B747-400? What about B777?

As a side-note, it's still possible to use "firewall thrust" in an airbus, but selecting N1 mode and set the levers to the Toga position regardless of outside atmospheric conditions. It'll just take a few seconds longer than on a classic steam driven airplane.

Regarding the black box being "too damaged to yield useful results" (assumning there is any substance to this): does anyone remember a similar case (impact into water, no fire, relatively quick recovery of the FDR/CVR) with such an outcome, especially with solid state based recorders ?

I muss say that I am very perplexed by this report.

"Damaged black box will give answers"
 

"A senior accident investigator in France has dismissed claims one of the black boxes recovered from the wreck of the Air New Zealand Airbus A320 which came down in the Mediterranean last week is too damaged to yield useful results.

A member of the multi-national investigation team has told the NZ Herald that black boxes are tested at such length and extremes it is rare to find absolutely no data.

The source, a senior accident investigator with decades of experience, said he knew of only one or two incidents when the memory cartridges had been compromised.

The black box equipment will be sent to manufacturer Honeywell in North America to determine what data can be extracted."

can anybody shed some light please why they haven't found the bodies of the other 5 guys, yet.

(does it mean the fuselage was obviously completely destroyed, broken into pieces and everything from inside plunged into the open sea?
Picking up the CVR and the DFDR, any information obtainable if the divers saw anything from the rest of the fuselage e.g. seperated in pieces or still intact ?

If you'd ever seen the effect of a relatively steep impact on an aircraft, or on the human body, you wouldn't ask such a macabre question....

CJ

Is it possible that when one says that "...no useful information could be extracted...", that it's in the context of an easy 'plug- in- cannon plug or USB and play' was impossible, but that Honeywell will crack the case and retrieve full data? I'm suggesting that perhaps the comments regarding the CVR and FDR were not well expressed, or not in their entire context, but in fact, we'll see the data extracted successfully by the manufacturer(?)...

I am not a pilot. I am, however, a retired electrical engineer who long worked for a semiconductor manufacturer in design, reliability, and manufacturing data analysis jobs.

Not very long after our first flash memory chips went in to one of the earlier solid state memory recorders, my reliability lab colleagues had quite a fire drill in assisting data recovery. It seems that in that case the recorder manufacturer's suspension had failed to provided a low-enough shock environment to at least one of the chips, and there was mechanical damage to the extent (if I recall correctly) of fractured wire bonds (yes--this was so long ago that chips were still connected to their pins by wire bonds). Anyway, the lab guys fiddled up an arrangement, the chip was read out, the accident investigation proceeded, and the reputation of solid state recorders was protected.

I suspect the housing/suspension was not very well done in that case. The old specs for bond wire integrity involved momentary accelerations in excess of 10,000 g, if memory serves me correctly.

They are not invulnerable. Actually as a crash survival medium, I'm pretty sure solid state memory of any kind is mechanically inferior to the old aluminum tape with scratchings, and probably also inferior to magnetic tape. But the survival has a lot to do with how well the recorder designer did his job, not just the medium. If it is going back to Honeywell, you only need to trust their greed to expect they will try really hard to get the data out. Their business and reputation have a stake in that outcome.

Holodek7,
I think you probably got it in one.
Getting data from a solid-state FDR or CVR can be as simple as hooking it up and reading it, or as complicated as having to remove every single memory pack from a smashed-up mess, reading it individually and reconstituting the data.
The problems in the wire and tape days were different, but of the same calibre....

archae86,
Nice one.
I know what you're saying.
Let's hope this time they don't actually need to get into the chip packs.

CJ

Yes. French manufactured aircraft, leased to German company by New Zealand company with German and NZ nationals on board crashed in France. Why would the NTSB have to be involved?

You obviously do what you must to keep from "spoiling your whole day", but you'd have to be VERY unlucky to break an engine in the minute or two "max available thrust" is used. I've seen engines abused per above that required nothing more than a special inspection, or perhaps some shroud/air seal replacement to restore performance, but no distress beyond that.

But use your good judgement. :ok:

What's your issue?
Some of the odds and sods on the aircraft are American, so the NTSB might be able to contribute something. Seems the FDR is Honeywell, so there you go.

CJ

I'm pretty sure that the NTSB won't get involved just to watch the french BEA because some folks think they ought.

The NTSB would likely ring up their BEA counterparts if there was a need for a thorough investigation of a US manufactured or designed part (I have not heard of any yet).

If the NTSB happen to have some black box readout experience that the BEA doesn't then the labs may get involved.

The long and short of it is that cross involvement under ICAO is mostly for technical reasons and not political reasons

A one-push GA only gives a 2000fpm climb at the required speed. A two push GA gives you full THR REF.

If you have Rolls Royce engines, selecting ALTernate EEC's could give you a lot more than you bargained for (That's why there are warnings in the manuals about selected ALTernate EEC's at full thrust). Definitely more than TOGA.

Rgds.
NSEU.

Press release to day from BEA :
Protected boxes (CVR and DFDR) have resisted and seem intact, but it was not possible to extract any data. Additional work will be becessary, without being possible today to predict their result.

If would say the result isn't too hard to predict.... :ugh:

BEA press release
 

I think this puts to bed the suggestion that they were returning to land as a result of a problem. A touch-and-go or simple overshoot was intended:

"L'avion était en approche sur Perpignan pour une remise de gaz et un départ sur Francfort"

Airbus Crash in France + recorder data missing....

haven't I heard that before..... :mad:


by the way, the CFM-56 on the 37NG I fly may be 'firewalled' as long as you have the EEC protections - it will produce slightly higher than max. rated thrust and Boeing even encourages you to do so during low level windshear or terrain avoidance.

Why Would NTSB Be Involved?
 

Simply because, depending on the final results, certification of the aircraft to be flown by U.S. carriers might be affected.

NSEU - true, but in reality are you going to start reaching for alternate EECs in a scenario where you need maximum thrust immediately? By the time you've identified the switches (taking care not to accidentally turn off the hydraulics) it'll all be over. So in all practical terms you won't get anything more than TOGA from the 744.

Quote:
Why would the NTSB have to be involved?
There is no reason for the NTSB to be involved unless one of the parties (France, Germany or New Zealand) request their assistance for some reason.

The investigative process is none of their business and they have no remit.

The report that eventually will be circulated will be taken on board by the myriad certification authorities around the world (in the USA the FAA, NOT the NTSB) and each will decide on how it will act - most likely in concert with the others.