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All,
I have been reading Pprune for the last 5 years in order to build up knowledge of something I find fascinating. I've enjoyed the technical debates on Tech Log and many of the other forums along with R and N. I've always felt that when the "no amateurs" discussion has surfaced that I should support not banning them. After all, I read to learn, and if I feel I can frame it in suitably knowledgeable terms I would post a question or a view if relevant. surely others are the same. Regrettably reading this thread I have changed my view. The uninformed rubbish that has been posted here defies belief and obscures the pertinent and knowledgeable content that has been contributed. I believe you are right and some method must be found to return this board to what it was 5 years ago when I first, joyously, discovered it. I just hope that some way can be found that I may continue as "read only" on these fora (but still contribute to Jet Blast!). |
PJ2: can any MD80 fleet type operators tell us if these engines are FADEC controlled? And as for the "ban all non-pilots" calls, is it really worth potentially throwing out many babies with the bathwater for the sake of not having to put up with a bunch of idiots for a couple of weeks a year at most? |
The MD-82 doesn't have FADECs - it uses mech linkages to fuel control valves and other assorted bits.
General The airplane is equipped with two axial-flow, bypass, turbofan Pratt and Whitney engines. The JT8D-217, -217A and –217C (-219 operated as - 217A) engines have a normal static takeoff thrust rating of 20,000 pounds and a maximum takeoff thrust rating of 20,850 pounds. An automatic reserve thrust (ART) system is installed. In the event of an engine failure, the ART system, when operating, increases the thrust on the remaining engine. Each engine is equipped with an acoustic treatment in specific areas for noise suppression. The engine nacelles are supported from horizontal pylons by vibration-isolating side mount systems. The nacelles are isolated from the fuselage by a firewall within the pylon and by a secondary fireseal at the pylon fuselage interface. To provide additional protection, the secondary fireseal extends above and below the pylon on the fuselage surface. To achieve necessary nacelle compartmentation, a fireseal is installed aft of the rear engine mount, which provides separation of the accessory compartment from the reverser section. The nacelle ventilation system is designed to provide adequate cooling of engine and accessories and to prevent accumulation of combustible mixtures. For monitoring engine operation, an EPR (engine pressure ratio) gauge, thrust rating indicator, N1 and N2 tachometers, EGT (exhaust gas temperature) gauge, FUEL FLOW gauge with a FUEL USED readout, oil pressure gauge, oil temperature gauge, and fuel temperature gauge are provided for each engine. The left and right engine EPR gauges receive sensing signals from the respective engine air inlet pressure (Pt2) probe and the low pressure turbine discharge pressure (Pt7) probes. Engine pressure ratio (Pt7/Pt2) is a measure of thrust being developed by the engine that is displayed on the EPR gauge. Power to operate these gauges is provided by the respective AC bus. The thrust rating indicator is interfaced with the ram air temperature probe and digital flight guidance computer (DFGC) 1 and 2. Ram air temperature (RAT) and EPR LIM (limit) are displayed on the indicator. Mode buttons are provided on the indicator for selection of desired mode (T.O., T.O.FLX, GA, MCT, CL, and CR). The DFGC’s supply data to the indicator for automatic display of EPR LIM for mode selected. The left and right N1 tachometers indicate the respective engine low-pressure compressor rotor RPM as a percentage. The left and right N2 tachometers indicate the respective engine high-pressure compressor rotor RPM as a percentage. Power to operate these gauges is self-generated. The left and right EGT gauges indicate in degrees centigrade the temperature of the exhaust gas of the respective engine. Each gauge receives signals from temperature probes located in the exhaust gas path of each engine. Power to operate these gauges is provided by the Emergency DC bus. The left and right FUEL FLOW gauges indicate the rate of flow in pounds per hour that fuel is being delivered to the respective engine. A FUEL USED readout on each gauge displays a digital readout of fuel used in pounds by the respective engine. A FUEL USED RESET switch is provided to reset the FUEL USED readout on both gauges to 00000. For further description of FUEL FLOW gauge/FUEL USED readout and FUEL USED RESET switch, refer to Fuel section. Power to operate these gauges is provided by the respective AC bus. HTH. ECAM Actions. |
any news from the crew?
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If it was an uncontained engine failure, then it is luck, not aircraft design that makes an event either an incident or accident. It matters not, whether the control surfaces are hydraulically or mechanically actuated. If a piece of engine decides to pass through a hydraulic pipe(pipes) or cut a control cable(cables), the result is the same, reduced or no control. Put that at or around V1, Vr or climb, then it is down if the pilot flying to use every ounce of their training and experience to attempt to recover the situation.
Passenger aircraft are not designed to contain within its systems and controls, an uncontained engine failure. Thought and design goes into system redundancy, but you do not fire bits of hot engines at airframes and see what happens if?! You cannot predict which bit of engine will not be contained and where it is going to travel after it has left the engine casing and cowl. That is why engines are designed and tested to contain engine failures. Now, why did it fail? I do not have authorisation on the MD82, but jets are jets. They all use the laws of physics to work. I am making an assumption, so please feel free to flame me, but from what I gather from previous media statements is that their was a problem with a sensor that is used by various systems including thrust management, to derive a temperature. If this temperature was inaccurate, or missing, then it is possible that incorrect thrust settings could have been used or manually calculated, with a possible outcome of an over boosted engine. There would obviously be other parameters to watch such as engine temperature or N speed, but this could be just another hole in the cheese. The engine could have been on watch, with degradation being "on condition" monitored by repeat boriscope inspections, which would normally be OK within its normal operating margins, but on this day, it failed at precisely the wrong time. Lessons will be learned and god bless the people who have lost through this terrible event. |
lnav-vnav777,
See post #351. |
RoyHudd, Aileron Drag et al shame on you.
Perfect example of the elitist attitude that unfortunately also tars the image of your more open minded colleagues. I don't know if you've looked down from your pedestal recently but FYI pilots and engineers are not the only professionals involved in aviation. I think you'll also find that a large amount of the spam on this thread was contributed by some of your fellow super-human beings. Get a grip. :ugh: |
I've only been flying multi-engine jets, and making a living at it, for 32 years, so obviously I have much to learn. In fact, I've barely scratched the surface of all there is to learn about aviation.
But it seems to me that those who complain loudest about non-pros have the least to offer themselves. They are first to denigrate, last to contribute to the discussion, IMHO. I see it as a manifestation of insecurity or inadequacy when one resorts to insults and ridicule, but that's just me. I welcome all inputs, from pilots, engineers, passengers, and the simply curious, and will decide for myself whether or not to take in the message or reject it, thank you. This incident has given me a lot to think about as I set out on my next trip tonight. These pages have provided insight regardless of those who are put out by the non-technical intrusions. If the press wishes to peer within Pprune, more power to them. I hope they, too, can separate the chaff from the informed opinion. If a journalist takes it upon himself to read the entire thread, he will come away with a better perspective. We have nothing to hide, therefore why the concern about spies? |
Post 431
Thrust Reverse operation is inhibited by A/C not on ground.
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BenThere - I couldn't agree more.
The press are capable of spouting rubbish without reading a darn thing on the subject. Can we get back on topic, please? ECAM Actions. |
Thinking a little further, I wonder if Danny and co could arrange for a little "verified industry insider" icon to appear alongside ones login ID and also provide the ability to only see posts from the so verified PPRUNErs if desired.
That way, you get to choose what you see and respond to. As to the comment about this thread changing the view as to whether non-aviation types should be allowed, I thought it was no different to the initial BA038 thread in this regard. Actually, learning how to recognise and ignore the clearly ill-considered from the knowledgeable is one of the small enjoyments of this sort of place. But it does mean you need the time to read and digest. |
' Passenger aircraft are not designed to control ( substain or constrain, my words ) ' an engine failure ?
Unless very unlucky with the hot end disc, I really reckon they ARE... Yours, airmchair pilot and experienced ( fighter ) test & development team member, who obviously ought to be chucked off this site for not being a 757 etc aircrew - In the brief time I have left before being buried in 'Jetblast', How many actual airliner aircrew / airliner engineers & designers agree about ' containment' being designed in - though a few instances lately seem to indicate it is still a goal rather than achievement ? |
I smell a RAT
Ram Air TURBINE has nothing to do with temperature.
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Double Zero -
Using your words, you are correct. Using my word "uncontained", then I will stand by my understanding of aircraft design. |
On the pro vs non-pro debate. Obviously I am not a pro. I am a PPL who loves all aviation. While only a 600 hour PPL, I am current and own my own aircraft. I strive to operate it in as professional a manner as possible, and I have much to learn from the pros here. While this accident bears little resemblance to what can happen with a Beech C23, nonetheless I think all pilots can learn from every accident, even if that lesson is simply to never take things for granted.
That, and I have a sentimental love for the DC-9 series; many many hours as SLF aboard one, including in the jumpseat when such things were allowed, and my first ever jet flight (and second ever airline flight) was in a DC-9, as an 11 y.o kid way back in the late 60s (the outward leg was a Viscount...). That said, many here, I have noticed have engineering/science backgrounds in non-aviation fields (I myself do in physics and chemistry, and vibration analysis). They can bring interesting info to table provided they, and we, understand the limits of their knowledge. This can be particularly useful in the Qantas analysis, regarding the storage of high-pressure gases and the physics an chemistry of the gas in question. Lastly, with regards to lurking journalists, I would hope that perhaps some of them will actually gain a bit more appreciation for the complexities of aviation, and will at least learn to get basic facts correct, such as not confusing a stall with an engine failure (which happened in Canada's national newspaper recently). Also, they might learn how and where to search for data before making inane comments about the safety of a particular aircraft series that in fact has a pretty normal safety record. One hopes... 'nuff said, back to reading what the pros have to say. |
Skyken, Total air temperature (TAT) is also called: indicated air temperature (IAT) or ram air temperature (RAT)
There's a discussion on smartarses like you in the last few posts. Please read them. |
skyken:
I mentioned RAT...and said NOT ram air turbine in this case. RAT can also mean "ram air temperature". I asked if the MD80 had a Ram Air Temperature gauge or a total air temperature gauge. I flew the DC9 and it had a Ram Air Temperature and it might have changed with the MD80. Just like TR can mean thrust reverser it can also mean transformer rectifier (or teddy roosevelt for that matter). |
Originally Posted by skyken
Posts: 4
Title: "I smell a RAT" Ram Air TURBINE has nothing to do with temperature. Yes, 'RAT' can refer to a 'Ram Air Turbine', as on Concorde. In this case it refers to a 'Ram Air Temperature' sensor, which is simply another term for a 'TAT', i.e., 'Total Air Temperature' sensor. Were your three earlier posts of the same calibre? CJ |
ECAM_Actions;
Superb descriptions/schematics from the book, thank you. I suspected the installation wasn't FADEC-controlled but wanted to be sure. delorean79; Can a Pilot deploy full reverse on flight, flying a MD80? That said, I know of at least one DC9-32 series, (not an MD80 series) where it did occur at cruise altitude and we know of the Lauda Air B767 accident which was apparently a FADEC fault. Most fleet types have an emergency drill (memorized...) for reverse deployment in the air. The drill usually involves appropriate rudder input, (foot/rudder pedal in the kitchen and then some), ensuring directional control, and shutting the engine down. FADEC-controlled engine designs on the Airbus (CFM56 installations and likely others) command IDLE thrust if a reverser-deployed signal is sensed in the air. That also said, most AOMs caution that controllability is a significant issue. For the record and for knowledge of non-pilots, going around after reverse is selected is absolutely prohibited. An accident (PWA B737, Cranbrook BC) led to this warning for crews. NOTE: None of this post or discussion is to be taken as speculation that a reverser was deployed in the air as a possible cause. This is simply not known. This is only an informal professional discussion on the operational aspects of reverser deployment in the air to which crews are trained to respond. |
It was dissapointing to see a disgruntled Spanair Pilot on TV stating how hard they worked, even stating he had to fly 5 days in a row, up to a maximum of 15 hrs a day. We all know that Spanish FTL is quiet flexible (have they moved to EU Ops Sub Part Q?) but only the investigation will hint if fatigue could have been a factor.
It would be better if he supported his Employer and work colleagues at this truly sad time :\ |
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