HYDRAULIC SYSTEMS . How is Yellow Hyd. Sys pressurized? A1. The Yellow hydraulic system is pressurized by a pump driven by engine 2. An electric pump can also pressurize the yellow system, which allows yellow hydraulics to be used on the ground when the engines are stopped. Crew members can also use a hand pump to pressurize the yellow system in order to operate the cargo doors when no electrical power is available. Q2. In which of the hydraulic systems, engine driven pumps are installed? A2. Green and Yellow. Q3. Name some of the major users of the GREEN system? A3. Some of the major users of Green system : -–> Landing Gear–> Slats/Flaps–> Normal Brakes–> Rev Eng 1–> Yaw Damper 1–> Stabilizer–> Some Flt. Control surfaces. 10 Facts They Didn’t Tell You About Malaysia Airlines Flight MH370. Nord 2501 Noratlas: no more uneven cargo floors! The Nord Noratlas was designed for the French Air Force as. Galloway says the flaw resided within Myspace’s account recovery page. When a user tried to recover their account, they were asked to enter their full name, email. An Airbus A340-600 due to be delivered to Etihad Airways jumped its chocks during an engine test at Toulouse on 15th November. The nose went up and through a blast fence. Air France Flight 447 (AF447/AFR447) was a scheduled passenger flight from Rio de Janeiro, Brazil to Paris, France, which crashed on 1 June 2009. The antiskid braking system adapts braking pressure (applied manually or automatically) to runway conditions by sensing an impending skid condition and adjusting. One of the several brave robots to make one-way trips into Fukushima Daiichi Nuclear Power Plant’s severely damaged reactors has accomplished what its less. Flying technique; back to the top; Airbus Braking Recommendations; Airbus pilots will find in this Airbus briefing lots of information concerning braking recommendations. FlightAware compiles, aggregates, and processes data from over 50 government sources (in Europe, the Americas, and Oceania), dozens of airlines, commercial data. Horrific final details of the final minutes of the doomed jumbo were revealed before it plunged into the sea off Brazil. Q4. Name some of the major users of the BLUE system? A4. Some of the major users of Blue system : -–> Emerg. Gen.–> Slats–> Rudder–> Some Flt. Name some of the major users of the YELLOW system? A5. Some of the major users of Yellow system : -–> Flaps–> Alt./Parking brake–> Rev Eng 2–> Yaw Damper 2–> Rudder–> Stabilizer–> Nose Wheel Steering. ![]() Q6. Name the components in Green Hyd. Components in Green Hydraulic system : -–> Eng 2 Pump–> PTU–> Green Reservoir–> Eng 1 FSOV–> Accumulator–> Priority Valve. Q7. When does Blue Pump energize. The Blue pump energizes on the ground with the Blue Elec. What is the purpose of the priority valve installed in Hydraulic Systems? A8. The priority valves cut off hydraulic power to heavy load users if hydraulic pressure in a system gets low. In the event of low hydraulic pressure, the priority valves maintain the operationof essential systems by cutting off hydraulic power to heavy load users. Q9. What happens to the yellow hydraulic system when a cargo door is being opened or closed? A9. When a crewman sets the lever of the cargo door manual selector valve to open or close, it inhibits the operation of other yellow system function (Except Alternate braking & Eng 2 Reverser). What is the purpose of the engine fire shutoff valves? A1. 0. Each of the Green and Yellow systems has a FSOV in its line upstream of its EDP. The flight crew can close it by pushing the ENG 1(2) FIRE P/b . The FSOV isolates the hydraulic system from its respective engine to prevent the spread of fire. Q1. 1. What is the PTU and what is its purpose? A1. 1. PTU is short for Power Transfer Unit. It is s bi- directional power transfer unit which enables the Yellow system to pressurize the Green system & vice versa. It comes into action automatically when the differential pressure between the Green and the Yellow systems is greater than 5. ![]() Q1. 2. Is it possible to pressurize the green hydraulic system on the ground via the PTU? A1. 2. During cockpit preparation if you start yellow electric pump, will green hyd. When does the PTU operate? A1. 4. The PTU operates when the differential pressure between the Green and Yellow systems is more than 5. Q1. 5. Will the PTU operate during Cargo Door operation? A1. 5. What are the conditions when PTU will not run . The following are the conditions when the PTU is inhibited from operating : -–> PTU inhibited during first engine start–> If Green/Yellow Reservoir overheats–> If Green/Yellow reservoir has low air pressure–> If Green/yellow reservoir has low fluid level–> Parking Brake ON and only one ENG MAST ON–> NWS in towing position and Parking brake ONQ1. When is the PTU self tested? A1. 7. PTU is self tested during the second engine start. Q1. 8. During PTU Operation, can fluid be transferred between green & yellow hydraulic systems? A1. 8. PTU transfers only pressure. It does not transfer liquid. Is it true or false? A1. 9. If there is a Lo Level in one of the Hyd. System, Is this hydraulic system still available or lost for the remainder of the flight? A2. 0. If there is a Lo Level or OVERHEAT of the reservoir in G or Y Hyd. Sys, is PTU available? A2. 1. Which of the Hyd. Sys is pressurized by RAT? A2. 2. How can the RAT be deployed manually? A2. 3. The flight crew may extend the RAT at any time by pressing the RAT MAN ON P/b on the HYD panel on the overhead or by pressing the MAN ON P/b on EMER ELEC PWR panel o the overhead. Q2. 4. Why there are two guarded p/bs for extending RAT manually on overhead panels? A2. 4. The 2 guarded P/b’s are on two different panels on the Overhead. One on the HYD panel and the other on EMER ELEC PWR panel. By pressing the RAT MAN ON P/b on HYD panel, the RAT powers only the hydraulic system through the Blue system. By pressing the MAN ON P/b on EMER ELEC PWR panel, the RAT also powers the EMER GEN for emergency electrical power generation. Q2. 5. If there is a Low Level in Blue Hyd. System, can RAT power Blue Hyd. When do you get FAULT light in G or Y ENG PUMP s/w p/b? A2. 6. The FAULT Light comes on and ECAM caution appears if : -(a) The reservoir level is low(b) The reservoir overheats(c) The reservoir air pressure is low(d) The pump pressure is low (inhibited on ground when the engine is stopped). Q2. 7. When do you get FAULT light in PTU s/w p/b? A2. 7. The FAULT Light comes on Amber and cautions appears on ECAM if : -(a) The Green or the Yellow reservoir overheats.(b) The Green or the Yellow reservoir has low air pressure.(c) The Green or the Yellow reservoir has a low fluid level. Q2. 8. If you have AIR DUAL BLEED FAULT, will there be loss of Hyd. Give reason supporting your answer? A2. 8. Yes, there will be loss of Hyd. This is because the system automatically takes bleed air pressure from the cross- bleed duct, but in case of dual bleed fault, there is no bleed pressure from both engines, hence even with the cross- bleed valve open, there would be no air pressure to pressurize the reservoirs. Q2. 9. When do you get FAULT light in BLUE Elect pump? Will there be FAULT light in PTU also at that time? FAULT Light come son Amber if : -–> The reservoir level is low–> The reservoir overheats–> The air pressure in the reservoir is low–> The pump is delivering low pressure–> The pump overheats. No, there won’t be a Fault Light in PTU at that time as the PTU is not connected to the Blue system. Q3. 0. When do you get FAULT light in YELLOW Elect pump? Will there be FAULT light in PTU also at that time? The FAULT Light in Yellow Elec. This is because in these cases the PTU is inhibited from operation. Q3. 1. What happens when you press the guarded RAT MAN ON p/b on Hyd. The RAT extends and powers the Blue system. Q3. 2. How to reset HYD PTU FAULT if it appears during engine start? Why it will come during engine start? A3. 2. It can be reset by switching the Yellow Elec. It comes on when the second engine is started within 4. As the PTU is inhibited from operation during cargo door operation and it is tested during the second engine start, the Fault comes on indicating that the PTU is not operating. Q3. 3. Why do you switch off PTU first in HYD OVHT or HYD LO LVL in G or Y Hyd. System before switching ENG PUMP OFF? A3. 3. This is done so as to prevent the PTU from automatically coming on and running the respective faulty hydraulic system which has an Overheat condition or a low fluid level, thereby overheating the PTU itself and ultimately leading to the good hydraulic system also getting into an overheat condition. Q3. 4. If you have lost green hydraulics system, what other check list may have to be followed by the crew in approach? A3. 4. If you lose yellow hydraulic system in flight, which of the systems are not available? During landing roll or after landing when you come for parking what caution has to be followed with Y SYS lost? A3. 5. The following systems are lost : -–> Yellow Hyd–> SPLR 2+4–> CAT 3 DUAL–> ALTN. BRAKE–> REVERSER 2–> CARGO DOOR–> YAW DAMPER 2. After landing, for parking, the Parking Brake may be inoperative, hence parking brake should not be used and chocks should be in place before shutting down Engine 1. Q3. 6. If there is a Lo Level in Yellow Hyd. System in flight, will you get NWS after landing? A3. 6. What is the purpose of the hand pump? A3. 7. The hand pump can be used to pressurize the Yellow system in order to operate the cargo doors when no electrical power is available. From ECAM HYD page: Q3. When will the Reservoir quantity symbol becomes Amber? Which ECAM caution will be generated? A3. 8. The reservoir quantity symbol becomes Amber for the following values : -(a) < 3. L for Green/Yellow(b) < 2. L for Blue. ECAM caution : - HYD G(Y)(B) RSVR LO LVL . Q3. 9. When does Reservoir LO AIR PRESS appear Amber on HYD page? Which ECAM caution will be generated? A3. 9. Reservoir “LO AIR PRESS” appears Amber when the air pressure for the indicated reservoir drops below normal.(a) For Green/Yellow/Blue, if reservoir air pressure < 2. ECAM caution generated : - HYD G(Y)(B) RSVR OVHT. Q4. 0. When does Reservoir OVHT appear Amber on HYD page? Which ECAM caution will be generated? A4. 0. The reservoir overheat appears Amber when the temp. Is there any difference in ELEC OVHT and Reservoir OVHT on HYD page? What is that? A4. The difference is that in the former, the pump has overheated whereas in the latter, the hydraulic fluid temp. By switching PTU OFF, what change do you see on HYD page? A4. 2. The PTU legend on HYD page becomes Amber. Q4. 3. You will be seeing letter 1 and 2 near ENG PUMP on HYD page. What happens to it when N2 is below idle? A4. 3. It becomes Amber. Footnote: Tremendous efforts have gone into making this page. People involved with Project Airbus Tech (PAT) have spent countless sleepless nights to make this page possible for you. The least you can do is to support us by giving us our due credit. No part of this page may be copied, or distributed, or used for any commercial purposes. For any uses, please CONTACT THE FLYING ENGINEER. Thank you for supporting us, and thank you for giving us our due credit. Air France Flight 4. Damn it, we’re going to crash’ In the early hours of June 1 2. Air France Flight 4. Rio de Janeiro to Paris went missing, along with 2. The Airbus A3. 30- 2. It took a shocked and bewildered Air France six hours to concede its loss and for several agonising days there was no trace. It was an utter mystery. No other airliner had vanished so completely in modern times. Even when wreckage was discovered the tragedy was no less perplexing. The aircraft had flown through a thunderstorm, but there was no distress signal, and the jet was state- of- the- art, a type that had never before been involved in a fatal accident. What had caused it to fall out of the sky? There is no doubt that at least one of AF4. It will be a grievous blow for Air France, perhaps more damaging than the Concorde disaster of July 2. And the reason for that fatal lack of awareness lies partly in the design of the control stick – the “side stick” – used in all Airbus cockpits. The company has sold 1. It commands half the world market in big airliners, the other half belonging to its great American rival, Boeing. So remote was the place the airliner went down, in equatorial waters between Brazil and Africa, that it was five days before debris and the first bodies were recovered. Finally, almost two years later, robot submarines located the aircraft’s flight recorders, a near- miraculous feat that revitalised the biggest crash inquiry since Lockerbie. It appeared to be a failure of the plane’s pitot (pronounced pea- toe) tubes – small, forward- facing ducts that use airflow to measure airspeed. On entering the storm these had apparently frozen over, blanking airspeed indicators and causing the autopilot to disengage. From then on the crew failed to maintain sufficient speed, resulting in a stall which, over almost four minutes, sent 2. Normally an A3. 30 can fly itself, overriding unsafe commands. Even if systems fail there is standard procedure to fall back on: if you set engine thrust to 8. How was it that three pilots trained by a safe and prestigious airline could so disastrously lose control? Either there was something wrong with the plane, or with the crew. Airbus and Air France, both with much to lose, were soon pointing accusing fingers at each other. For Air France the conclusion was crushing: the crew had ignored repeated stall alerts and kept trying to climb, instead of levelling off or descending to pick up speed. The A3. 30 had become so slow that it simply ceased to fly. Its reputation on the line, Air France came as close as it dared to repudiating the finding. The pilots, said the airline, had “showed unfailing professional attitude, remaining committed to their task to the very end”. All indications suggested the aircraft had functioned just as it was designed. The black box recordings showed that the plane was responsive to the point of impact. The case against the pilots looked even worse when a transcript of the voice recorder was leaked. It confirmed that one of the pilots had pulled the stick back and kept it there for almost the entirety of the emergency. With its nose pointed too far upwards, it was little wonder that the Airbus had eventually lost momentum and stalled. But this analysis begs the question: even if one pilot got things badly wrong, why did his two colleagues fail to spot the problem? The transcript of increasingly panicky conversations in the cockpit suggests they did, but too late. Many passengers, including five Britons, would have been trying to grab some sleep, only half aware of the turbulence buffeting the A3. There were eight children onboard, including Alexander Bjoroy, an 1. Bristol’s Clifton College. Also travelling was Christine Badre Schnabl and her five- year- old son, Philippe. She and her husband had purposely chosen separate flights to Paris, possibly because of their shared fear of air crashes. He had taken off earlier with the couple’s three- year- old daughter. His deputy, David Robert, a seasoned flier with 6,5. AF4. 47 was flying towards. Eight minutes later, everyone on board would be dead. Bonin himself seems to have been spooked, calling attention to a metallic smell and an eerie glow in the cockpit. Robert reassured him that it was St Elmo’s fire, an electrical fluorescence not uncommon in equatorial thunderstorms. A few moments later the outside air temperature plummeted, the pitot tubes iced up and an alarm sounded briefly to warn that the autopilot had disengaged. From this moment, Bonin’s behaviour is strange. The flight recorder indicates that, without saying anything, he pulled back on the stick and, seemingly against all reason, kept the nose up, causing a synthesised voice to warn, “Stall! Stall!” in English as the airspeed began to drop dangerously. Robert took 2. 0 or 3. Bonin to descend. It says we’re going up, so descend.” Seconds later Robert again called out, “Descend!” and for a few moments the plane recovered momentum and the stall warning ceased. But Robert was now anxious enough to call for the captain to return to the cockpit. Meanwhile, Bonin’s instinct was again to pull back on the control stick. He left it there despite the stall warning that blared out some 7. Instead of moving the stick forward to pick up speed, he continued to climb at almost the maximum rate. If he had simply set the control to neutral or re- engaged the autopilot, all would have been well. Bonin was apparently so disorientated that he believed he was operating at low altitude, in a similar situation to a pilot having to abort a landing approach before circling for a second attempt. Standard procedure on abandoning a landing is to set engines to full power and tilt the aircraft upwards at 1. But Flight AF4. 47 was not a few hundred feet above a runway. Within a minute it had soared to 3. As forward thrust was lost, downward momentum was gathering. Instead of the wings slicing neatly through the air, their increasing angle of attack meant they were in effect damming it. In the next 4. 0 seconds AF4. The wings were now like bulldozer blades against the sky. Bonin failed to grasp this fact, and though angle of attack readings are sent to onboard computers, there are no displays in modern jets to convey this critical information to the crews. One of the provisional recommendations of the BEA inquiry has been to challenge this absence. An A3. 30’s angle of attack is measured by a fin projecting from the fuselage. When forward speed fell to 6. The computers, which are programmed not to feed pilots misleading information, could no longer make sense of the data they were receiving and blanked out some of the instruments. Also, the stall warnings ceased. It was up to the pilots to do some old- fashioned flying. This is what David urged Bonin to do, but something bewildering happened when Bonin put the nose down. As the aircraft picked up speed, the input data became valid again and the computers could now make sense of things. Once again they began to shout: “Stall, stall, stall.” Tragically, as Bonin did the right thing to pick up speed, the aircraft seemed to tell him he was making matters worse. If he had continued to descend the warnings would eventually have ceased. But, panicked by the renewed stall alerts, he chose to resume his fatal climb. It is here that Airbus’s cockpit design may be at fault. These side sticks are not connected to the aircraft control surfaces by levers and pulleys, as in older aircraft. Instead commands are fed to computers, which in turn send signals to the engines and hydraulics. This so- called fly- by- wire technology has huge advantages. Doing away with mechanical connections saves weight, and therefore fuel. There are fewer moving components to go wrong, the slender electronic wiring and computers all have multiple back. Better still, they are programmed to compensate for human error. Once a command is given, say a 1. According to Stephen King of the British Airline Pilots’ Association, it’s an admired and popular design. As King concedes: “It’s not immediately apparent to one pilot what the other may be doing with the control stick, unless he makes a big effort to look across to the other side of the flight deck, which is not easy. In any case, the side stick is held back for only a few seconds, so you have to see the action being taken.” Thus it was that even when Bonin had the A3. It seems clear from the transcripts that Robert assumed the plane was flying level or even descending. Robert himself was panicking: “We still have the engines! What the hell is happening? I don’t understand what’s happening.” Ninety seconds after the emergency began the captain was back in the cockpit demanding: “What the hell are you doing?” To which both pilots responded: “We’ve lost control of the plane!” Dubois took the seat behind his colleagues and for a while was as perplexed as they were. It was pitch black outside, warning lights were flashing and some of the screens were blank. The men in front partially blocked his view and evidently he did not take much notice of a horizon indicator, which must have shown the plane was still being held nose up. The Airbus was soon falling through the night at 1. Only 4. 5 seconds before impact Bonin blurted out that he had been trying to climb throughout the emergency, giving his colleagues the first indication of what had been going wrong. There is one final, dramatic exchange: 0. Robert) “Climb. Robert realises the ghastly truth – that he hasn’t enough height to dive to pick up speed. The flight is doomed. Some of the passengers might have dozed throughout the descent; others may have attributed it to violent buffeting. Those in window seats would have seen only darkness. There is reason to hope that there was not too much panic on board, but this is small consolation. And yet that is how their latest generations of aircraft are designed. The reason is that, for the vast majority of the time, side sticks are superb.
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