Re: being a mechanic for a 787

Most airlines have specific in house schools for each aircraft fleet. Most are about 3-4 weeks long with classroom and on aircraft training. For Delta an AMT is required to have a fleet school to be authorized for certain tasks. From a regulatory standpoint is it optional to be trained on a specifi...

Re: Can steel brake pads be used in systems designed for carbon?

A little over 2000 cycles for our 777s I believe. No idea about the rest. That is about right, depending on how the aircraft is being used. For our 777F it's a little over 1400. Of course they're heavier than a pax aircraft, so there is more wear. Our MD11F brakes were good for a little less than 2...

Re: Autobrake question: MAX vs. RTO, and performance (and pax)

On the B777 the aircraft aims for a specific deceleration, depending on the autobrake selector position. Autobrake 1 is 4.0ft/sec² with a maximum brake pressure of 1385psi. 2 is 5.0 ft/sec² at max 1600psi 3 is 6.0ft/sec² at max 1850psi 4 is 7.5ft/sec² at max 2150psi MAX AUTO is 11.0 at max 3100psi R...

Re: Differences between Airbus and Boeing troubleshooting

Boeings Fault Isolation Manual and Airbus' Troubleshooting Manual basically work the same. They make you do some checks and tests and depending on the result have you replace the component that's most probably faulty. Test again and if the fault continues, replace the next component and so on. At so...

Re: being a mechanic for a 787

Thanks for your replies. So basically it's a case by case thing. The airline defines how they want to handle maintenance and employee training and the FAA says yea or nay. There's no basic regulation, did I get that correctly? I work under EASA regulations where it is define pretty precisely how cer...

Re: being a mechanic for a 787

Most airlines have specific in house schools for each aircraft fleet. Most are about 3-4 weeks long with classroom and on aircraft training. For Delta an AMT is required to have a fleet school to be authorized for certain tasks. From a regulatory standpoint is it optional to be trained on a specifi...

Re: Portable External Oil Cooler

We never defuel our aircraft before maintenance unless it is absolutely necessary. Defueling is very expensive. Not only do you lose the fuel you already paid for, you have to pay for its disposal. Once fuel enters an aircraft it cannot be resold. It could be used to refuel other aircraft of your ow...

Re: Tail Anti-Ice leading edge question.

deebee278 wrote:

True, most airliners don't have tail deice. However, there is a major exception, the MD80.

Re: Dirty airplanes

EK and Qatar stand out as premium airlines because of how clean their planes are. You’d be hard pressed to see a dirt mark from the jetway. They have the advantage of living in the desert. Dry dirt doesn't stick. Wet dirt does. Look at photos of aircraft stored at VCV that have been there for many ...

Re: Flaps working slower ??? (airbus)

I think we have to clarify the existing conditions first. Did we lose the entire green system, meaning no pressure at all? Then it's half speed. Single System Operation The loss of the hydraulic pressure to one of the two motors causes the power off brake to apply and hold the motor output shaft. Th...

Re: A320 pushes nose down in flare mode

I can't answer for Boeing, but on Airbus pitch control in Normal Law is loading proportional to stick deflection. Regardless of speed, if you pull back a certain distance on the stick, you get a certain g loading. My understanding, which may be flawed, is that this would not work in the flare. As y...

Re: A320 pushes nose down in flare mode

It isn’t a reminder to flare. It’s done to simulate the back pressure that’s held during the flare of a conventional aircraft, as that’s far more intuitive to pilots. The 787 and 777-9 have a similar feature that basically does the same thing. The classic 777 does it as well, I just checked. The bo...

Re: Flaps working slower ??? (airbus)

@Horstroad: The fluid flow will increase because the one HYD pump has to pressurize Two HYD systems. The yellow system, as in normal ops, and the green system via the PTU. Thats why we have the PTU. With the PTU pressurizing the green hydraulic system the flaps would extend/retract at the normal sp...

Re: A320 pushes nose down in flare mode

If a pilot doesn't do anything it would end up on the NLG. I've never seen it go down to -2, but then again, I've always applied back pressure as that is what is taught from your first flight in a single engine piston DA-20/C152/C172. I don't think any pilot would intentionally let the plane put it...

A320 pushes nose down in flare mode

According to the FCOM and other documentation the A320 family aircraft push the nose down automatically when the flight control system goes into flare mode: The system memorizes the aircraft's attitude at 50 ft, and it becomes the initial reference for pitch attitude control. As the aircraft descend...

Re: Flaps working slower ??? (airbus)

The flow in through the hydraulic motors is the same. The same amount of turns is required to extend or retract the flaps a set distance no matter how many motors drive them. Why should the fluid flow increase? However as Spock540 pointed out the load for the motor would change. Both green and yello...

Re: Question about quotation on MD-11 landing speeds.

The horizontal stabilizer and elevators are about 30% smaller compared to the DC-10. That's why you need more speed to keep a certain level of control authority. Fun fact: When approaching FRA, ATC would often ask for todays mini-clean speed, the minumum speed in clean config (flaps and slats up), t...

Re: Unusual GSE

Here's the video thumbnail:




I assume it's for bags of used bed linen, blankets, pillows and stuff like that. Trash is usually collected by the caterer.

Re: Fly-by-wire project help

Basic CRM teaches that only one pilot should be in control at a time. The takeover buttons assist with this. If the sticks were moving, they would not directly indicate surface position. The instruments indicate aircraft attitude and attitude trend. If you can't read the PFD, I don't think seeing a...

Re: Do any jetliners sometimes require packs-off approaches?

The MD-11 does that. When the aircraft is between 4k and 1k feet and the engines are in T/O thrust mode or when the aircraft is below 1k feet and in air mode the PACKs will be switched off automatically. Additionally when both wing anti ice and tail anti ice are not switched on pneumatics are switch...

Re: Tire Pressure on A32X Family

But what difference would it make if we keep the same pressure for Nose wheel on longer jets. Won't it ensure fleet commonality? Under- or overinflated tires wear unevenly. While an underinflated tire is much worse than an overinflated tire you don't want either. An overinflated tire has less conta...

Re: Fly-by-wire project help

The system design of the side stick did. The two side sticks are not connected and there is no feedback from the control surfaces. The B777 does both even though it's full FBW as well. I could probably list half a dozen recentish accidents of aircraft with fully connected controls still managed to ...

Re: Fly-by-wire project help

FBW has caused problems, like contributing to AF447 IMHO FBW on its own did not contribute to AF447. The system design of the side stick did. The two side sticks are not connected and there is no feedback from the control surfaces. The B777 does both even though it's full FBW as well. I don't want ...

Re: Engine Start Procedure. Which one first?

The start sequence on the MD-11 is 3 - 1 - 2. The APU is rubbish. Engine start has to be performed with packs off. Once eng #3 is running the pneumatic system #3 can be isolated and pack #3 be operated again. Same for system #1. System handling (packs off/on, isolating the systems, APU shut down, et...

Re: Avionics Bay Access and Pressurization

I would think the crew would want access to the E&E in the event of a fire. To let air into the fire and smoke into the cockpit? Not sure how smart that is.... The equipment down there is ventilated anyways. It's not sealed off. Usually you can throw stuff down to the E&E compartment fwd of...

Re: DC-10 tail mounted engine angle

The inlet duct has indeed an angle of about 2° to follow the shape of the fuselage. The engine itself however is mounted horizontally level. edit: As you can see here there is a 2.5° angle between the inlet duct centerline and horizontal and again a 2.5° angle between the inlet duct centerline and t...

Re: Source of bleed air (CFM engine)?

The "intermediate" probably refers to the pneumatic system. Usually three pressure values are important for pressure regulation. PE (Engine Pressure), PI (Intermediate Pressure) and PM (Manifold Pressure). The engine pressure sensor sits upstream of the high stage valve, so it's the HPC ai...

Re: Altimeters, static pressure, and lift

An interesting question and I had to think about it for a few minutes. The static pressure component of the total air pressure changes only when you compare pressure values before and after you have accelerated the air, e.g. infront of and right on top of the wing. This drop in static pressure in co...

Re: Airspeed lost

I don’t think you can get an A319 to do 320kts IAS at FL390 The Airbus protections would prevent the overspeed. There is no way to have the aircraft to reach that speed using autothrust with the autopilot engaged. The maximum indicated airspeed of an A319 at FL390 is 250kts at M0.82 indicated. The ...

Re: Blue Hydraulic Pump/System in an Airbus? How does it work?

I don't think the question is Airbus specific or even axial piston pump specific, but rather a question of the basic principles of hydraulic power. If I understand your question correctly you're concerned about the fluid trapped in the cylinder on the pressurized (red) side being rotated around to t...

Re: 737 MAX APU Inlet Door

In my aircraft you never operate the APU inflight unless you need it for non-normals, relight, hydraulic pressure, electric power, etc. What aircraft has an APU that produces hydraulic pressure? For the original question I guess they changed the design to reduce drag and increase fuel efficiency. A...

Re: Which airliners have two jackscrew assemblies to control their horizontal stabilizer?

How do these multiple jacks operate then if one hydraulic system goes down - with a jackscrew being irreversible? Unless they're placed in series (one after another) I guess, rather than in parallel (side by side) as you'd expect I can't see how they'd work. On the MD-11 the two nuts are connected ...

Re: Which airliners have two jackscrew assemblies to control their horizontal stabilizer?

The DC-10/MD-11 has two

Re: "...low cycle fatigue fracture of a torque tube"?

You are right that there is a separate torque tube inside the ACME screw

Any of these commands activates one of the two
electric motors that rotate the acme screw by applying torque to the titanium torque tube
that is held fixed inside the acme screw.

Re: "...low cycle fatigue fracture of a torque tube"?

Addenum. I think from the information on the diagram and description on page 15 that the torque tube is inside the acme screw. It is said to be made of titanium. The acme screw was recovered after the accident. Still not clear on how the fracture of the torque tube led to the fatal dive. The ACME s...

Re: Teal Color Inside A320neo Pratt & Whitney Engines

StereoTechque wrote:

The black inlet cowl also has visible holes on surface for Accoustic dampening.

Re: Teal Color Inside A320neo Pratt & Whitney Engines

I was really surprised that posters were suggesting that the teal liner was an attrition/abradable lining. As you point out, the teal material extends many inches ahead of the fan. So it's not that, folks! Yes, it is. No It's not :P https://i.postimg.cc/MK30WrtC/5961041-2.jpg

Re: Teal Color Inside A320neo Pratt & Whitney Engines

So back to OP's question? Why blue? Does it also have acoustic dampening properties (perforations, etc.) as the differently colored lining ahead of it? It's a honeycomb core panel with a perforated face sheet. Its purpose is noise reduction. The color is probably just the base color of the epoxy ma...

Re: "THR CLB" v. "THR LVR"?

LVR is an abbreviation for "Lever". The Airbus thrust lever does not have a LVR or "lower" detent. There is a TO/GA detent for Maximum Take Off or Go-Around. There is a FLX/MCT detent for Maximum Continuous Thrust or Flex Take Off and there is a CL detent for Climb Thrust. Thrust...

Re: Teal Color Inside A320neo Pratt & Whitney Engines

The Fan Blade Rubstrip (or Abradable Shroud or Attrition Lining or whatever they're called by other manufacturers) is in the plane of the fan blades. In the pictures of that PW1000G series engines it would be the light gray ring behind the teal colored ring. The teal colored ring should be acoustic ...

Re: Restrictions on #2 Thrust Reverse L1011/DC10/MD11

I’m just wondering what the lockout prodcedure is for an MD-11. I remember on a 767. Installing 3 red lock plates on the outside of the trans cowl and flipping and installing a locking square drive in the center drive unit It's the same. Additionally you have to disconnect the electrical connector ...

Re: Why fuel driven actuators?

The engines can't run without fuel. They can run without hydraulics...

Re: Use of rudder in commercial aircraft

On the 777 Thrust Asymmetry Compensation is a protection function of the Primary Flight Computer operating in Normal Mode. It starts to operate when the CAS is >70kt, the reversers are not commanded deployed, and the thrust difference between the engines is at least 6000lb. TAC is limited to 60% of ...

Re: Restrictions on #2 Thrust Reverse L1011/DC10/MD11

We didn't have such restrictions.

Funny thing is, if there was a stuck reverser or any other engine problem, there was a more than 1/3 chance it was #2. Not because of maintenance, #2 always got the same love as the others. She did it just because she could.

Re: Is it dangerous when aircraft carry fuel in a center tank beneath the passenger cabin?

on planes that had/have the horizontal stabilizer tank, is that used primarily for feeding the APU? The primary purpose of the tail tank on most aircraft is for CG control. Secondary would be additional fuel storage space. On the MD-11 the APU shares the fuel feed line with the #2 engine. It has a ...

Re: Duration of 747 Hydraulic Pressure Reduction?

Aircraft that have flaps that are driven by actuators…the MD11 or DC8 come to mind…will have check valves and/or restrictors that prevent the flaps from drooping with loss of pressure. The MD-11 had the issue when you would pressurize the #2 hydraulic system without pressurizing the other two hydra...

Re: UPS 747 takeoff without flap fairing

I figured it was the Preamble. The MMEL available on MBF doesn’t have that. I’ll have a peak at it at work tonight I never work with the MMEL, I think I never even had a proper look into it. There never was a need to. But I have an old copy of a MD-11 MMEL from '00 on hand and just skimmed through ...

Re: Rather neat holes in 9V-SQJ

My guess is on plane tags. What I find more surprising is the fact that they didn't strip it of parts before scrapping, except for the engines and some cockpit windows. Thrust reversers still in place, slats still there... An old aircraft is usually worth more in parts than whole. If it was my aircr...

Re: UPS 747 takeoff without flap fairing

But there's MEL 9.5 I don’t know what that is. It's the Preamble of the MEL. The section "Contents of the MEL" describes what is and isn't contained in the MEL and how it has to be treated when it isn't. For example Equipment obviously basic to airplane airworthiness such as wings, rudder...

Re: Is it dangerous when aircraft carry fuel in a center tank beneath the passenger cabin?

The center wing tanks usually are the largest. On the 777 (-200LR/-F/-300ER) for example the center tank holds 184,480lb and the wing tanks 69,630lb each. I think some early versions of the 777 didn't use the space in the center wing box for fuel. The two compartments of the center tank in the wings...