texts: Would connecting propeller blades with a continuous ring reduce induced drag?

texts:
Turbine engines are covered, which of course is to contain the process (just like a super/turbocharged engine is as soon as the air enters the intake). But it got me thinking, doesn't this also reduce - or even completely remove - the induced drag around the tips of the fan blades?

Would it be possible to have a similar setup for a standard prop, it doesn't even have to be stationary, it could be a ring connecting the tips of the prop, spinning with it, like an infinite winglet.  It has the added safety benefit that it'll be visible when the prop is spinning. And I figure if the ring is strong enough to maintain its circumference, the load on the prop should be marginal since it's spinning around its own center of mass.

Is the induced drag on the prop not large enough to warrant any thought, or would such a prop-winglet-ring (I'm sure there's a real name for it, anyone know what I'm talking about?) cause other disruptions of the airflow? Or perhaps there are other reasons, like it would simply be too hard to solve for constant-speed props?


texts: Why do ground crews rotate a radial engine's propeller before a motor/cartridge start?

texts:
In footage from WWII you often see the ground crew rotating the propeller of a radial engine a number of times before the pilots start the engine.

I know it's not the same as hand-starting (hand-propping).

I read somewhere (but questionable source) that it has to do with the oil sitting down in a radial engine.

As far as I know, the oil surrounds the cylinders on the outside. If the oil is cool and not yet expanded, what will a few turns do to it?


texts: Why can such a small difference in thrust make such a big difference in maximum speed?

texts:
I was recently comparing two aircraft, and, although I feel stupid asking this question, I wondered why one had a maximum speed of M2.2 compared to M0.94, when both have similar weight, both are supersonic capable and both have similar thrust.
Compare for example the Hawker Hunter F.6 which has:

Empty weight 6,406kg
Max speed M0.94 (>M1.0 In a dive)
Engine thrust 10,145lbf
Climbrate 17,200ft/min

And the Mirage F.1:

Empty weight 7,050kg
Max speed M2.2
Engine thrust 13,700lbf (WET)
Climbrate 16,400ft/min

As you can see, both have similar rates of climb, similar empty weights, and both are aerodynamically supersonic capable. Only major difference being the the F.1 has ~35% more thrust- yet, with this extra thrust and weight, it is able to go over twice as fast? How does this work?
As I write this the only thing I can think is that wave drag plays a part, and the afterburner is required to give it that extra boost to break through the transonic barrier?
If the above is the case, then does this mean that all aircraft that can supercruise require the use of afterburner to get there, but can then hold it in mil power? And, if so, could this mean theoretically you could use a rocket booster of some form to push the Hunter F.6 through the transonic region and hold a supersonic speed, or, is there a minimum thrust to weight ratio in mil power required to achieve supercruise, or do more special aerodynamics need to be involved to keep wave drag down to make it possible?


texts:
Suppose we have an aircraft flying in steady, level flight at zero angle of attack. In this configuration, the velocity vector $\vec{V}$ is perfectly aligned with the $x$ axis. At some time $t=t_0$, the pilot applies a finite positive rudder input $\delta_{r}$ which produces a yawing moment on the aircraft. My question is what will happen to the velocity vector immediately after the rudder input gets in.

From my understanding, as soon as the the pilot inputs the rudder, the plane produces a positive side force (in the $y$ direction), which causes a negative moment about the $z$ direction. We can write this as something like $N = -l_vY_v$, where $l_v$ is the distance from the vertical tail to the CG, and $Y_v = C_{L_v}Q_vS_v$ is the side force as mentioned above. We can write this in non-dimensional form as the yaw moment coefficient, i.e.
\begin{equation}
C_n \equiv \frac{N}{Q_wSb} = -\eta_vV_v\frac{\partial C_L}{\partial\delta_r}\delta_r,
\end{equation}
where $\eta_v = Q_v/Q_w$ and $V_v = l_vS_v/(Sb)$. So, a positive rudder deflection will give a negative yaw moment, as seen in that equation, proportional to $C_{L_{\delta_r}}$. However, this doesn't tell me anything about the velocity vector. Intuitively, I would think that after a long time when the aircraft has time to stabilize itself, the velocity vector would point along some angle $\beta$ from the $x$-axis relative to where to was before. However, I am not sure what would happen immediately. Maybe there is an immediate sideslip angle, and over time it decreases (assuming the aircraft is stable). Thanks for the help in advance!


texts: Can you disengage A320 autopilot with stick pressure?

texts:
I was recently reading that in most military jets, auto-pilot can disengaged without hitting the button, by applying 5lbs of pressure to sticks.

Does this work in commercial airliners such as the A320?


texts: Can we submit and sign the 8710 in IACRA after the check ride?

texts:
I work at a 142 school and was told we can submit and esign the 8710 after the check ride.  The digital esignature shows a date time stamp 9-hours after the beginning of the oral and flight exam. I have always had everyone submit and esign the 8710 before any event and completed it after the event with the result.
Thoughts?  Is there any regulation or FAA guidance one way or the other?


texts: Why are these carrier aircraft landing with the canopy open?

texts:
I was reading this answer here Aviation.SE, which includes the following video of multiple F7U-3 Cutlasses landing aboard the USS Hancock in 1955 (warning, video includes footage of a fatal rampstrike):

I notice that each and every pilot is landing with the canopy open. Why is this?

I'm not a pilot, so these are uneducated guesses:

It could be opened for visibility reasons, except I'm guessing it'd be forward visibility that's be most important, and the sliding canopy doesn't do that any obvious favors. And according to Wikipedia, the plane's high cockpit was already designed for good visibility for carrier landings.

My other guess would be that the canopy is opened in case of a bad landing/fire (less bad than the rampstrike later in the video), and the pilot has to get out in a hurry. But I doubt it'd make a huge difference as the pilot's (presumably) still strapped in. And if he can open the canopy while on approach to a carrier landing, it's probably fairly straightforward.

Last guess would be that it's in case the pilot has to eject, yet he should be able to do that, open canopy or no. Besides, the seat would still hit the canopy upon ejection, it seems - maybe just-in-case to avoid the pilot's head hitting first?


texts: What is an Air Defense Identification Zone (ADIZ)?

texts:
China recently caused some controversy by announcing an Air Defense Identification Zone (ADIZ) in the East China Sea. There is also an ADIZ surrounding most of North America.

What exactly is an ADIZ and what does it take to fly across one? For example, what would be necessary to fly a private plane directly from Apalachicola to Cedar Key, Florida?


texts: Why do planes overfly Moffett Field before landing?

texts: I live near Moffett Field, and I noticed that some airplanes go over the field once before landing, along the runway (not across), even when the tower is open. I thought that was a procedure for non-towered airports only?


texts: How are forces on the landing gear reduced or compensated for at touchdown?

texts:
When an aircraft lands with the tires of the landing gear at rest, as soon as the the aircraft touches down, the landing gear experiences a large amount of wheel-spin up forces (because of the static friction involved between the stationary tires and the relatively moving runway at a very fast speed), which even cause it to vibrate at some frequency. This force is considered to be highly undesirable.

Are airplane manufacturers using any kind of measures to reduce these forces on the landing gear at touchdown? How are they compensated?


texts: What are the minimum requirements for passing medical for PPL?

texts:
Where can I find the UK requirements to pass the medical exam for a PPL?

Basically I would like to check my health and all the requirements with any doctor - I have health insurance plan, and when I know that I meet all the criteria I go back to the aviation doctor for checking and issuing the certificate.


texts: Why do the CRJ700 window shades open in different directions?

texts: On a CRJ700, the window shades in the rows immediately fore and aft of the exit doors open downward. All the rest open upward. Seen on more than one aircraft. Is there an engineering rationale for this?


texts: Is there a limit to how many hours a person can fly per month?

texts: I'm trying to figure out whether there's a maximum per person.  Of course factoring in eight hours of sleep and say maintenance time there is definitely a limit, but I don't see where it is.


texts: Is there a way to integrate recorded digital media evidence into a pilot report?

texts: If I encounter something during flight that I feel other pilots in the area at that time need to be aware of, the standard procedure is to file a pilot report.  If I have taken a photo or video of the phenomenon or incident, is there any way to integrate this digital media evidence file into the pilot report?  Can you type in website(s) link(s) to the digital media?


texts: What is the main and tail rotor speed (RPM) for a Sikorsky S52?

texts: I need the RPMs for the main and tail rotor of a Sikorsky S52 for the research I am doing for my degree. I tried checking flight manuals and other websites, but I don't find concrete numbers, only percentage values.


texts: The F16 stick movement is little. But how?

texts: The F16 stick movement is very little, is 1/8inch. So there is just a stop point at the end of the movement, or the stick is  hard all the time, but move  a bit ? There is increase in stiffness to apply  full displacing of the stick?


texts: Is it allowed to launch powered paragliders from national parks?

texts:
I'm new to the sport and can't find a written answer. I've been told by local PPG pilots that it is illegal to launch from state/federal parks.

I live near Johnson's Beach, Gulf Islands National Seashore and was told by the officer at the gate entrance:

  Yeah, go ahead, use the parking area and beach to the west, we have guys that fly out of there regularly.


texts: How to say the name of this approach clearance: COPTER RNAV (GPS) 027°

texts:
JFK has this approach: https://aeronav.faa.gov/d-tpp/2006/00610COPTERR027.PDF

How is this approach said on frequency? Is it the "copter RNAV zero two seven approach" or the "copter RNAV zero two seven degree approach" or the "copter RNAV heading zero two seven approach" or something else?


texts: What types of antennas are used in a Piper Seneca PA34-200?

texts: What types of antenna are used in the Piper Seneca PA34-200 and where are they are located? The manual is not giving the specific answer to the question. Also, what is the frequency range of the antennas?


texts: What is the weather term for snow and dust mixture?

texts:
An old pilot friend of mine told me today a story that I thought was interesting.

He said that he was flying into Wichita, KS a couple decades ago and was listening to the ATIS when the weather report indicated snerd.  He called up the approach controller and asked what snerd was and the controller stated it was a mixture of the blowing snow and dust coalescing making a big mess.  The pilot stated he broke out of the clouds and all he saw was a brown mess all over the place.

Does anyone know if this is actually called snerd? If not, what is the correct term?


texts: Where to find approach plates for European aerodromes?

texts: Where do I find the approach plates for European aerodromes? Is there a website intended for pilots updated and certified from the authority?


texts: What is the initial direction from Sydney to Santiago on a great circle?

texts: When flying the great circle route from Sydney to Santiago, what direction do you head leaving Sydney? Does the path leave Sydney heading SE and approach Santiago strictly from the SW, like is shows in the graphic from this answer?


texts: Does stall angle of attack in inverted flight change due to the camber of an asymmetric airfoil?

texts:
What is the stall angle in an inverted flight configuration? How does it relate to the stall angle in normal flight?

As visible in the image below, in upright flight the lower pressure is on the extrados of the wing. In inverted flight the lower pressure is on the intrados.

(source)

The air stream separation at the stall will occur on a side with different characteristics. One could expect the stall will happen differently.

Equivalent representation, where the gravity is inverted and the wing orientation remains in the same direction. Flying inverted implies flying at a negative angle of attack.

The values taken into account are the airflow direction and the chord line, reflected in the angle of attack value.

As commented, while the two previous images suggest a wing in horizontal flight, the situation can be extrapolated to any stable linear trajectory with a negative AoA.

The horizontal plan or the pitch angle are not necessary to determine the stall angle (though they influence the stall speed).


texts: What is a counseling session with the FSDO/FAA?

texts:
I just flew into Bravo unintentionally 48 hours ago. My error: I thought I was 1,500 feet above the ceiling, but I was 1,000 feet below it.

Furthermore, I had an incorrect frequency for Approach, and while I eventually found the proper frequency (I'd planned to request flight following) I had crossed over the outer ring.

When I contacted Approach, the Approach Controller explained I was in Bravo, and to turn West and exit. I did say, "Am I not ABOVE Bravo airspace?" He said "No, you're in it" and to fly West and exit.

From that moment, I followed approach control's directions to a T, but could not understand why he directed me West (remaining in Class B for 13 more miles) instead of having me climb 1,500 feet or angle back North or North-West to exit Bravo more quickly.

I was given the dreaded phone number, made the call after landing, had a friendly enough discussion, and he said it would probably lead to a counseling session. My question is what is that?

I'm familiar with the remedial training option the FAA may offer, but what did he mean by "counseling session"? The controller implied it would be handled by phone.

I'm not freaking yet, just concerned. I told everything that happened on that phone call, and then filed an ASRS report.


texts: What is the climb-out angle of a twinjet upon one engine failure scenario?

texts: Take a typical 737-800 or A320 at MTOW how much difference in take off angle does a 1 engine out failure scenario make, compared with a normal 6-8 degree take off angle with full engines.


texts: Does weight and balance of an airplane matter more on takeoff?

texts:
On a few international flights with non-full cabin, the crew has asked no one to move to open seats until the plane has finished take-off. I assumed this was just to force people to sit down during take-off and not cause problems, but when I asked I was told it was because of weight. The claim is, the airplane is balanced by where people are sitting. The next claim is by the end of the flight, there is less fuel, so if people have switched seats there is less of a problem. This weight balance apparently uses all information, people, baggage, and fuel.

I believed this, until recently a plane had lost at least 30 peoples baggage, some people had more than 1 bag. The bags were left at the previous airport, and on arrival no one knew that the bags were not on the plane.

If the lack of knowledge for bags not being on the plane (which seems logical, why would they depart without the bags), how did this change in weight not show in the take-off, or was this a dangerous occurrence?


texts: What FAA sources of weather information can pilots use to mitigate the risk of flying in icing conditions?

texts: Pilots flying under the FAA jurisdiction have many official sources of weather information available to them. Specifically as it relates to icing conditions, what official sources of weather information can pilots refer to in order to avoid or mitigate the risk of flying in icing conditions?


texts:
I've been assessed and hired as cabin crew member by Easyjet in UK, on the 26th april I will have my medical assessment.
2 weeks ago I did a PRK refractive laser surgery for myopia correction. Today I've got another eyes examination that certified that there is not a refractive error anymore, that my visual acuity is better than aviation standards, that i'm not experiencing post-operative complitations or problematic visual effects as ghosting or halos or glares and so on... So actually all my eye functionality are giving great results.
Axa health medical requested me this report to send to CAA to be analysed and decide if I'm fit to fly and procede with my face-to-face medical assessment.
My worries concern not about the eyes visual standards but the TIME.
Could CAA reject me for a matter of time, even if from my eye surgery date to the start of training pass exactly 2 monthes?
Could CAA complain about a full eye report, even if completely successfull, that has been provided after 2 post operative weeks?
I know is trivial but I would be gratefull if someone could help me... Thanks


texts: Vortex Lattice Method with eliptical panels

texts:
I implemented vortex lattice method (or deeper here) into my aircraft simulation program. The problem is that sometimes trailing vortex filaments from Horse Shoe Vortexes of main wing hits panels of rudder/elevator which leads to singularities (infinite coupling between the two panels). This is because rectangular panels generate sharp singular vortex filament at the end of wing.
(see https://scicomp.stackexchange.com/posts/30062/edit)

I'm thinking to use eliptical panels as a basis set for VLM to avoid those singularities - then I hope my simulator can work with smaller number of panels (I wan't to make it real-time).

This is normally ploted in texbook:

My questions:

I search for formula / derivation how the down-wash from eliptical wing looks like in the whole 3D space. Usually what is plotted in texbook (constant rectangular downwash) is true just immediately behind the wing.
Is it fine to express wing of complex shape as linear combination of eliptical wings and it's downwash as linear combination of downwashes from each of them? I mean if potential flow is linear problem, than I see no problem - ut maybe I forgot about some catch.


texts: What makes the ailerons on an aerobatic airplane different than the ailerons on a non-aerobatic airplane?

texts:
I often hear a spec of the "roll-rate" when talking about aerobatic airplanes and the term "fast ailerons." What exactly does that mean, and what makes the ailerons on an aerobatic airplane different than the ailerons on a non-aerobatic airplane?

How does the design of the ailerons affect the roll-rate of the airplane?


texts: How often does fuel dumping from planes in flight actually occur?

texts:
There are a couple of questions about the emergency procedure of fuel dumping, used to reduce the weight of airplanes to be able to land.

This is certainly interesting, regarding environmental affects, safety aspects, and maybe some archaic fascination for huge fuel-air clouds.

How relevant these questions really are depends on how often fuel dumping is done.

But I don't know how often it is actually done, in incidents per year globally.

I understand that the procedure is used only in emergency cases, but not only in very few very extreme situations. It's about getting the weight down to be able to land safely, and the overweight is from fuel not yet used up on the flight.

So the procedure is needed whenever there is a need to urgently land, and there is not enough time to burn the fuel in flight.

That seems to mean that severe medical emergencies of individual passengers may be a reason? That happens much more often than drastic technical problems I assume, so it would be a strong factor.

Now, I'm interested in some rough total estimate about how often fuel dumping happens, and the main factors, like minimal emergency cases that can lead to a fuel dump.

I'd simplify the scope by considering only commercial aviation, ignoring military and general aviation - but I do not see that as important, use the data you have at hand.


texts: Was smoking banned because of passenger safety or occupational safety?

texts:
Federal regulation CFR 252.3 notes that:

  Air carriers shall prohibit smoking on all scheduled passenger
  flights.

Was this because of: 1) passenger safety concerns (the airplane may catch on fire from an unextinguished cigarette); 2) consumer demand (passengers demanded all-non-smoking flights); or, 3) for occupational safety concerns (the flight attendants were breathing in cigarette smoke all day)?

I've posted my own answer but am happy to be proven incorrect.

Related questions:

• When did inflight smoking become (widely) prohibited?

• Is it legal to smoke in your own plane?


texts: How does ICAO differentiate between Commercial and Private flights?

texts:
How is the difference between Commercial and Private/General Aviation flights defined by ICAO?

Here in the US, we use 91 flights -vs- 135 flights, but from what I've heard they use a different definition, particularly concerning business aviation flights that fall under Part 91.

In other words, what determines whether ICAO Annex 6 Part 1 or Part 2 applies to a particular flight?


texts: Do Jabiru aircraft have a long history of engine failures or other technical issues?

texts: I heard that a friend of mine experienced an engine failure in a Jabiru 2200. Does this happen very often and are there other common failures in the Jabiru family of aircraft?


texts: Why is "proverse" yaw better than no yaw?

texts: Why is the tendency to yaw in the direction of the roll more desirable (since it's the "proverse" yaw) than the lack of yaw in response to roll? Is it even possible to have no yawing tendency at all during rolls in a plane?


texts: Do commercial pilots have their own lavatory?

texts: I was wondering if commercial pilots had their own lavatory to the two instead of using a passenger lavatory.


texts: Why was the Sukhoi Su-47 Berkut never adopted for service?

texts:
This is a rather long question, since I try to cover the historical background which might not be widely known. If familiar with it, you can skip to the "highlighted sections".

As part of the programme equivalent to the U.S. Advanced Tactical Fighter (ATF), aimed at producing a 5th generation multi-role fighter aircraft, Russia (then USSR) produced (like the U.S. programme) 2 competing designs: one from Mikoyan and the other from Sukhoi. These were the canard/delta Wing 1.42/1.44 from Mikoyan and the FSW (Forward Swept Wing) Su-47 from Sukhoi.

Initially running parallel to the U.S. programme, due to mounting financial difficulties and the eventual collapse of the USSR, the 2 prototypes were ready more than 5 years later than their respective US counterparts (The 1.42/1.44 prototype was completed at 1994-5 but performed its first flight in 2000 while the Su-47 was completed in 1992-3(?) and flew in 1997).

Even before the collapse of the USSR, though, the Soviet Air Force had chosen the Mikoyan design as its next 5th-gen fighter.

Yet, after USSR's collapse, Sukhoi was able to finance its own project and have it ready earlier, while also running an R&D programme and further evaluating/improving the design. By the time the Mikoyan MFI performed its first flight, the Su-47 was already taking part in air shows while serving as a testbed for various technologies (many of them finding their way to PAK FA).

This raises a number of questions, all relating to why the Su-47 was not chosen, neither before the USSR collapsed, and secondly why it was not chosen in the 90s by Russia as it was clearly a design in a more mature stage.

  Was the basic design premise-that of a FSW fighter aircraft-flawed?

  Were the problems facing this configuration, relating mainly to wing durability, still insurmountable?

To be precise, a FSW design offers superior manoeuvrability, especially in low speeds, retaining an AoA (Angle of Attack) undreamed of by a "conventional" fighter, is essentially spin-proof, it has a better lift/drag ratio, lower stalling speed while it can help with low observability characteristics (Stealth) as radar beams impacting the wings are reflected to the fuselage , ideally one with a comprehensive RAM (radiation absorbent material) covering.

But a FSW design has a major drawback-the loads that accumulate on the wings during manoeuvring, are much greater than in a conventional wing, leading easier to deformation and structural failure. The Su-47 tackled this problem by making extensive use of composite materials for the wings which offer greater durability at less weight.

  If the FSW design was viable, was it a matter of economics?

After the USSR collapsed and Russia embarked on economic "reforms" its defence budget shrank dramatically for a decade and new procurement was very difficult. But after 1999-2000, gradually funding increased and when the need for a 5th gen aircraft became again apparent, the PAK FA (Sukhoi T-50) project began, around 2005.

But given that a design was already ready, namely that of Su-47, why not save all the expenses (PAK FA development is in the range of 10 billion US$) while gaining in terms of time?

I usually do not like to speculate on "What if?" historical scenarios but had the Su-47 been chosen, say in 2003-4, by now RuAF could have fielded a fleet of 100+ airframes (assuming initial production starting at about 2008-9).


texts: Calculations for altimeter settings for variations in barometric pressure

texts:
Pls help me with these 2 questions

An aircraft is standing on an airfield 220ft above sea level on a day when the barometric pressure at ground level is 1004 mb. If the pilot sets the altimeter to read 220ft on this day, what will it read if the barometric pressure drops to 992 mb.

An aircraft sets off from airfield A (126 ft above sea level) where the ground pressure is 1010 mb and flies to B (762 ft above sea level) where the ground pressure is 985 mb. If the pilot sets his altimeter (incorrectly) at 26ft at A, what will it read when it lands B?


texts: Why do GPS Copter Approaches require a slower final approach speed than conventional Copter Approaches?

texts:
AIM 10-1-2 says helicopter instrument approaches are designed with a maximum speed of 90 KIAS. However, it specifically exempts the final segment on GPS helicopter approaches, saying the maximum speed there is 70 KIAS. Here is the explanation in the AIM:

Obstruction clearance surfaces are based on the aircraft speed and have been designed on these approaches for 70 knots. If the helicopter is flown at higher speeds, it may fly outside of protected airspace.

Why are GPS copter approaches designed with a different obstacle clearance surface that requires a different airspeed on final? Also, if a helicopter flew faster forward with the same descent rate, wouldn't it get farther from the obstacle clearance surface (i.e. making faster speeds safer)?


texts: What options are there to learning IFR flying on Garmin's G1000 (Cirrus Perspective)?

texts:
I am about to begin my IFR training.  I can do this in a 5-year old 172 with the G1000 at a reasonable price.  I need a good tutorial or book for learning IFR with the avionics on which I plan to learn.  In particular, I do not first want to study avionics that I neither have seen nor operated, only so that I can then unlearn them and relearn how the G1000 has morphed their functionality.  Ideally, I would take a course that imagines that IFR was invented together with the G1000.  My particular situation is likely to become more common over the years, too, with wider spread of the G1000 and alike.

I have searched the net.

There is a book by Max Trescott, but it dates from 2012.  It is 2018 now.  Has the G1000 software since 2002 received some good or important updates ?!
There is an expensive course by King Schools.
There are the official Garmin manuals.

Are there any other options for training on the G1000? What are the advantages and disadvantages of these options?

Note: I am not affiliated with any of these vendors, nor do I have any information.  I am just looking for discussions of pluses and minuses of updated G1000 IFR books, courses, and tutorials.


texts: Why doesn't the autobrakes and ground spoilers deploy on the A320 if the speed is below 72 knots?

texts: I really can't understand the reason as to why Airbus has put a speed restriction of 72 knots for the activation of autobrakes and deployment of ground spoilers. Could someone explain why this has been imposed?


texts: Could an airliner abort a landing after using the brakes system while landing?

texts:
Everyone knows that doing a go-around is a normal procedure, although the go-around happens usually before applying the brakes system (spoilers, ground/air brakes, and/or thrust reversers), but, could you perform an aborted landing after using any brakes system?

Of course, this is not for a normal flight/landing, and there must be some conditions, like enough runway to gain speed again, and of course you should be not so low from Vr speed.

Let's see why someone could do an aborted landing after braking: There were at least two cases (Atlantic Airways Flight 670 and TAM Flight 3054) where the braking system just "fails" (actually both were a pilot's error, but let's say that was just a mechanical error).

Of course you will only notice that the braking system is failing when you activate it, and maybe is not like they are not working at all, but just working poorly, so you could see that the speed is slowing down, but also you can see that is not normal and maybe you just need to takeoff again and do another approach, or even going to another airport for a longer runway so you could safety brake with your malfunctional braking system.

After that explanation, I have two questions:

Can you technically perform an aborted landing after braking? I mean, could the automated braking system or the flaps settings interfere?
Would be this procedure be in any airline/airplane manual in case of a malfunctional braking system while landing? (i.e., an official procedure for this type of case)


texts: Which FAA regulations cover the certification of aircraft engines?

texts: Aircraft certification is covered by 14 CFR 23 and 25, what parts cover aircraft engines?


texts:
I need some advice on designing a propeller for a UAV and choosing the right motor for it. I am doing a project which requires the fix-wing UAV to travel at cruise speed of 20 m/s and weighs a total of 12kg, the propeller will have to be a pusher and the aircraft has a L/D of 35 at cruise. I am told by the lecturer to ignore take off velocities as it takes off on a seperate VTOL system before the propeller is activated at 300m for horizontal flight.

As a mechanical engineering student I don't have much experience in aerodynamics. So far I've looked into blade element theory and airfoil designs but there are many different variables to consider such as airfoil profile, pitch, angle of attack, diameter and I'm at a bit of a lost on how to determine these values to match the UAV requirements. So I would like to ask what is the best way I can go about doing this? The ultimate goal is to maximise flight time by designing a propeller and reducing power requirements.


texts: Descending while turning inbound on a non-precision approach

texts:
I'm writing my instrument rating examination soon and one of the questions that I came across was:

  While executing a VOR A RWY 01 approach for Alexander bay, 2700ft is reached at 8DME on the outbound leg. The most appropriate action would be to:

  level off and turn inbound before descent
  continue outbound and descend to 2500ft before turning inbound
  turn inbound while descending to 2500ft >>> Correct

Now some background info: Alexander bay's VOR approach outbound leg ends at 8DME 2500ft.

I would say answer 1 is correct, however the answer is stated to be no. 3
Is it because it's a NPA? I was taught never to descend while turning inbound and that it is sloppy flying/poor planning. So this answer doesn't really make sense to me.

I tried looking it up in 8168 and the ICAO docs, but I haven't had any luck.

This is the plate:

Source: caa.co.za (PDF), click image to view


texts: What is the formula for estimating the maximum stationary thrust of a rotor as function of its diameter?

texts:
I am new! New to this forum and new to aviation (i normally deal with statics) so thanks in advance for beeing patient with me.
Recently i was trying to figure out how much weight a rotor can lift as a function of the rotor diameter.
Therefore I came across this formula.
$$
T_{rotor} =(0.5*P^2*η_{rotor}^2*η_{el}^2*π*d_{rotor}^2*ρ_{Air})^{1/3}
$$
This brings me already quite close to my goal as I now have $ Thrust = f(P^2, d^2)$. Now I tried to relate the engine power to the rotor diameter by using :
$
P=T * {rpm}$  with $ T=I *α=(0.5* m*r^2)*v_{sound}/r $  and $ {rpm}=v_{sound}/(\pi*d)$
Which leads me to
$$
P(m)=(v_{sound}^2/(4*π))*m
$$

From this calculation a few questions arise:

Do you think this is a good estimate (within +-15%)?
Is there a better formula to estimate $I_{rotor}$ than using $I_{zylinder}$?
Is there any formula to estimate $ m_{rotor} = f(d_{rotor})  $

I want to add  that this estimate is for a rough feasability study and not to design a rotor or aircraft. I also know that several of the values in this formulas are a function of altitude and aircraft velocity. Please dont take this into account. At the moment I am only interested in a stationary solution.
Thanks for your help!


texts: What is the aerodynamic benefit of trailing edge sweep?

texts:
I know that the sweep will allow the flight to fly at higher speed because the perpendicular air flow speed (over wing) is less.

But I didn't understand why there is trailing edge sweep?

We can have a swept leading edge and unswept trailing edge to produce elliptical lift distribution. Also, unswept trailing edge will help to improve flap effectiveness, right?

Could someone please explain this to me.

Thanks in advance


texts: Can an aircraft be docked at the gate from the right seat?

texts:
Not all aircraft can be docked from the right seat, because they have a wheel tiller only on the captain's side, but some can (e.g. the B747-400 of the linked question).

The usual docking system at gates looks like this:

(source)

It seems the azimuth guidance is based on parallax, and is designed for the left seat.

What happens if the pilot in charge of docking the aircraft is seated on the right side? How is the alignment performed without the support of the visual docking system?

Related: Are large passenger aircraft steered during taxi by changing the angle of the front landing gear?


texts: Jettison and Dump fuel - Do they have separate meanings?

texts: According to the definitions, is there any difference between Jettison and Dump fuel?  Does one of them use a different procedure, or they are simply synonyms?


texts: What kind of tools are available to an ATC handling traffic in the terminal airspace to predict aircraft trajectories?

texts:
I know that the ATC has feedback on the current position of the aircraft via Radar and ADS-B data. However, are there any tools to forecast future trajectories. For example, say an aircraft is scheduled to arrive at an airport and will reach within the coverage of the terminal airspace ATC in the next 5-10 minutes. Does any tool help forecast that aircraft's trajectories based on filed flight plans? Does the ATC pay attention to the aircraft only after the pilot has established contact via voice?
Similarly, let's say the ATC assigned some vectors and maybe allocated a runway to an aircraft. Does any tool predict the trajectory the aircraft would follow so that any future vectoring or allocations can be planned?
If such tools are not available, what is the ATC process for handling terminal airspace traffic?


texts: What are the reasons for using an instrument approach on a clear day / CAVOK?

texts:
As a new VFR pilot, I was wondering why anyone would fly (or be assigned) an ILS (or other) approach in clear weather?

I ask this because I watched Vienna - Tokyo (Narita) on PilotsEye.tv where the F.O. flew the approach looking at the display all the way until the flare. The visibility was good. Runway 34R.


texts: Do helicopters fly holding patterns under IFR?

texts: If a helicopter is flying an IFR flight plan, and the airspace around the destination is busy, will controllers tell them to fly holding patterns just like planes do? Or will they hover at the holding fix? Or something else entirely?


texts: Why would the propeller of a lightsport plane or ultralight w/ Rotax engine be connected to the engine through a clutch, and not turn at low rpm?

texts:
Why would the propeller of an ultralight or lightsport plane be connected to the engine through a clutch, and not turn at low rpm?

I've often witnessed the engine start of a Bailey-Moyes Dragonfly (link to flight manual, links to cool you-tube videos but not showing engine start #1, #2) and the prop did not turn until the motor rpm was increased substantially above idle.  It was clear that some sort of automatic clutch was not engaging until the engine rpm was increased above idle.

It would seem that any sort of clutch that would allow the engine to run without the prop turning would add un-necessary complexity.  So why was this feature incorporated into the drive train of some versions of this aircraft?

I'm rather sure I was told the answer to this once, but I've forgotten.

I know that the aircraft in question was powered with a Rotax engine, but several different Rotax engines have been used on this type of aircraft, and at present I'm not able to identify the specific one I witnessed where the prop was not turning at idle.  It seems likely that many other aircraft powered by the same engine would use the same gearbox with the same automatic clutch feature.


texts: Does the direction of counter-rotating props affect efficiency?

texts:
From my brief Wikipedying, if counter-rotating props' tops go towards each other, each has a reduced P-factor so the loss of either engine won't yaw the aircraft as hard as if the bottoms come together.

As I don't really care about safety of my aircraft's occupants (usually a couple ants after it sits on the grass) or reliability, I'd prefer to increase the P-factor for fun and flat spin potential. Out of curiosity, does the direction of counter-rotating props (rather, counter- or similar- in a twin) affect the efficiency?


texts: How much cheaper would flying be if we made it less safe?

texts:
Comment: I know this doesn't represent reality, it is a hypothetical scenario.

I have the impression safety measures are non-linear in cost, i.e. that reducing the accident rate by one percent costs more than the preceding percent. We often go to great lengths (and costs) to eliminate very unlikely events from happening.

Let's just assume that we would tolerate the fatality rate of aircraft to be 10 times as high as it currently is. Flying would be even more  attractive and cheaper than going by car (replacing cars on more distances) and would still be statistically safer, so there would still be less fatalities overall.

Is there an estimate on how much the ticket price for end passenger could decrease if we allowed for this to happen? The usage case would be the average commercial aircraft on for instance a 2-3 hour short haul flight.

For instance:

Reduce number and frequency of maintenance checks.
Dispatch aircraft to their destinations under less stringent Minimum Equipment Lists.
Have lower pilot requirements.


texts: If I am transiting a class delta airspace on a VFR flight and am coming up to a class bravo boundary without a bravo clearance, what will happen?

texts: Kind of an edge case, but will the class delta controller ask me to "say intentions"? Or maybe let a bravo controller know I could be entering without permission?


texts: Most time-consuming tasks while a plane is on the ground

texts: How long should commercial planes stay on the ground after landing before they can take off again? What is the most time-consuming thing/task/operation that happens during this time? Is downloading maintenance data from a plane time-consuming?


texts:
What is difference between Block hour and Flight Hour?

In ACMI Lease of aircraft, prices are calculated based on block hours. What is a block hour and how are they calculated?

Can any one show me an example for a flight like this...

Delay at Runway (takeoff): 20 Minutes
Flight Time: 1 Hour and 40 Minutes

Then what could be block hours? 2 Hours or 1 Hour and 40 Minutes?


texts: Can you identify this antenna on a Cessna 172N?

texts: Does anybody know what this antenna is used for?  I suspect a glideslope antenna but I am not totally sure.


texts: How different is flying through Free Route Airspace (FRA)?

texts:
I understand the flight planning and ATC aspects of Free Route Airspace. I'm trying to understand what a pilot does differently while flying in an FRA. Are there changes to standard procedures while transitioning from ATS routes to FRAs and vice-versa?

How does the pilot handle deviations/re-routing from a planned route (typically a straight line between the chosen Entry and Exit points), especially when this can pose risks of conflicting with routes of other aircraft flying in the FRA?


texts: What is the significance of the exclamation mark (!) on ACARS page of a Boeing 737?

texts:
For a while now I've noticed an exclamation mark on the ACARS inflight page of the B737NG at the beginning of a flight. It is located in the top left corner of the page and it just disappears after a while. I've been searching high and low what it means but can't find it.
Any ideas?


texts: What is the difference between "flight level" and "altitude"?

texts:
I have seen references to "FL180" and "FL300", and I know that they stand for Flight Level 180 and Flight Level 300. I've also seen references to "an altitude of 18000ft" or "an altitude of 30000ft".

What is the difference between flight level and altitude, how do they relate to each other, and when and why would one be used instead of the other?


texts: Who owns wrecked airplanes in international waters?

texts:
Reading about a Spanish treasure ship, I found that it eventually created a dispute between the company that found it (Odyssey) and the Spanish government, so the following questions came to my mind (focused on an international ocean wreck):

Is the same ownership law applicable to wrecked ships and wrecked planes?
Is there any difference between floating debris and sunk debris?

More specifically, regarding Malaysian Flight 370, who owns the debris discovered at La Réunion?


texts: Does official source of data about air routes exists?

texts:
I'm interested in the information about air routes of all the world. I need information with following features:

it must be official (not stolen, without violating any license);
it should be in digital form;
it should be in WGS84;
it should cover all of the world;
it should be free (no payment);
it shouldn't be detailed (just main routes);
it shouldn't be actual (current), one or two years outdated is appropriate.

I've realised that some kind of this information is published by ICAO at the AIP, but I can't find it.

So my question is: whether such information is available and where I can find it?


texts: What determines in which direction a runway is used?

texts:
A nearby airport has a single 05/23 runway (3900m long), where airplanes start and land in one direction during certain periods and in the opposite direction during other periods.

How is the direction determined -- I assume it's air traffic control which decides that but based on what ? (wind, sun ?)


texts: How dangerous is flying in a single-engine plane?

texts: Some people consider flying small planes very dangerous. Just how dangerous is it to fly in a light single-engine plane? For example, how does the fatality rate compare to driving a car, riding a motorcycle, etc.?


texts: What is the vertical speed limit when altitude mode is engaged?

texts:
This question applies to Airbus' autopilot but may not be restricted to just this manufacturer (there must be equivalent modes on ATR, Embraer, Dassault Falcons, etc.)

For the vertical plan, the autopilot offers different modes. Among those, there are V/S where it tries to keep the selected vertical speed, and Alt, where it tries to keep the selected altitude.

When in Alt mode, if the aircraft is not at the required altitude, then the autopilot commands a vertical manoeuvre to reach the desired altitude. My question is: during this manoeuvre, is the vertical speed limited and if is this limit configurable in flight by the pilots? (If not, I imagine it is limited to what can be achieved in open climb or open descent modes.)

EDIT: The question comes from the hypothetical situation where aircraft is flying towards a target altitude and the pilots want to limit the vertical speed for any reason (e.g. a better vertical separation with another traffic)


texts: Mnemonics to distinguish popular airplane models

texts: When in the airport I'd love to be able to distinguish most popular aircraft from each other, how can I say that a plane I am looking at is say a320 or 737 etc? They look so similar. I can detect 747 for 4 huge engines, but that's as far as I can go.


texts: How does one choose the number of blades and the diameter required for a turboprop propeller?

texts:
I am interested in the preliminary design of a regional aircraft that uses turboprops as the propulsion method.
Following considerable research online about propeller design (disk theory, BEM...) I am rather lost on where to start.
To put it short, what parameters must be considered when designing the propeller of a turboprop device?
I am mainly interested in obtaining an idea of how many blades would be required and the diameter of the prop.
I have obtained values for the engine power requirements, and from what I can gather the main reason to have an increased number of blades is due to the requirement of absorbing the power from the engine. The latter therefore implicating an increased solidity ratio.
Is the any standard formula/theory that can provide such answers?
Thanks,
FZ


texts:
During my commercial ground school today, we were asked if turbojet and turboprop aircraft are defined differently by the FAA. While I know the answer is yes, I don't know where in Title 14 the answer can be found. I've searched multiple resources for over two hours.
Thanks!


texts: Where can I find the roster formats of various airlines?

texts: I discovered a mobile app called roster minder for android. It seems that the app can import rosters from various airlines. I was wondering how that was possible? Is there a standard format for crew rosters or do airlines publish roster formats, which can be consumed by the app?


texts: Does the FAA or FSS check or authorise IFR flight plans?

texts:
There is an existing question about VFR flight plans the answers to which suggest that FSS dont check these and the main purpose of filing GA VFR flight plans is to aid subsequent S&R efforts.

You could therefore file a flight plan where some aspect is beyond the aircraft's capabilities (payload, range, altitude, GNSS, other equipment, etc).

How about IFR flight plans for chartered commercial flights for example.

The International Flight Plan form has a box labelled "ACCEPTED BY" but I assume this just indicates that the plan has been received and filed successfully, not that it has been checked for completeness, feasibility or safety or that it has passed some authorisation process.

For IFR flight plans, is there any FAA-mandated checking or authorisation performed by FSS or other quasi-official body at time of filing other than simplistic checking that something has been entered in mandatory fields?


texts:
When operators purchase new aircraft it seems that a Letter of Intent is frequently the means by which this is done. What does such a Letter of intent usually contain?

Bonus question: Would the letters of intent in the following two scenarios would look different:

Purchase of a new aircraft as the launch customer from and established manufacturer. For example: ANA was the launch customer for the 787, which was a new type certificate from company with an established track record of manufacturing airplanes.
Purchase of a new aircraft as the launch customer from a new(er) manufacturer. For example, Continental Express purchased 25 ERJ-145 at a time when Embraer was not an established manufacturer of commercial passenger aircraft.

Would the purchases in scenario 2 expect more/better assurances as part of the LoI  to minimize certain risks (e.g. planned partners, production planning, certification planning, etc.)?


texts: Semi-circular rule for choosing a FL: Risk of head on collision with borderline headings (179, 359)?

texts: If it happens that you fly a 179/359 heading in uncontrolled airspace, what's the risk of collision with aircraft flying in opposite direction?


texts: Is some sort of clearance, such as a clearance to enter nearby controlled airspace, required to legally fly in IMC in Class G airspace?

texts:
In the US, is some sort of clearance, such as a clearance to enter nearby controlled airspace, required to legally fly in IMC in Class G airspace?
Or to put the question another way, in the US, may an instrument-rated pilot flying an IFR-equipped aircraft in Class G airspace violate the VFR cloud clearance requirements without an IFR clearance, without violating any FARs other than (the rather ambiguous and subjective) FAR 91.13?
Does it make any difference to the answer if the pilot is NOT following any specific established instrument approach or departure procedure?  For example, if the pilot is taking off from an airport for which no instrument approaches and departures have been established?  Or if the pilot is flying in one of those now-rare bits of airspace where the class G ceiling is well above 1200' AGL?


texts: Should I add balloons in my Ultralight wing to help it float if I land in the water?

texts:
I like to fly over rivers and lakes in my ultralight. One of the things that scares me the most is if my engine died, I might drown down in the depths of the water as I egressed out of my ultralight.

My Hy-Tek Hurricane has an aluminum front and rear spar, with a few spreader tubes, and then it has simple aluminum tube ribs which slide into pockets in the Dacron wing covering. This leaves nothing but empty hollow space inside 99% of my wing.

Has anyone ever thought of adding some lightweight durable air-filled balloons inside their ultralight wing to add buoyancy in case of a water landing which would almost certainly flip my tricycle gear ultralight? As it is, the wing has plenty of gaps in it which would allow water to rush inside and sink my plane. I don't know how long that would take, but I would rather not find out!

My aircraft weighs just slightly less than 254lbs. So I would need approximately 254/8 = 31.75 gallons of air to maintain a neutral buoyancy, and I would probably want to add another 30% or so to that to turn my ultralight wing into basically a flotation raft if I ended up in the water.

So does anyone have any good ideas on what to stuff inside my wing so my little "ultralight" doesn't turn into an "UltraAnvil" and sink to the bottom with me drowning next to it? If I crashed in the water, I figure I probably have a 50/50 chance of extricating myself from the wreckage without drowning right away, considering the impact will probably knock the wind out of me. It would be difficult, but I think I could do it. If I was at a full stall when I touched down I think I would survive, but would certainly flip upside down, then it would be a mad scramble while upside down underwater to get the safety belt off and yank my helmet and it's wires off and kick free.

But if I CAN get out, the next problem is that I am fully clothed with shoes, maybe a ski jacket, gloves, jeans, thermals, and everything else. I have had an unlucky experience of being fully dressed while flailing in the river before when I dashed out to rescue an R/C plane once, and it was very dangerous, and I nearly did drown (I will never do that again!).

It sure would have been nice to have a partially sunk ultralight next to me to hang onto! So I was thinking balloons, because that would be easiest. I could just inflate maybe 100 balloons or so and then stuff each of them up in the zippered inspection seams, 50 in each wing. The weight would only be maybe 8 ounces or so of all the balloons, and I can't imagine that they would hurt anything inside the wing. Is this a good idea?


texts: Would USAF ATC experience help in getting a civilian ATC job?

texts: Can I join the US air force as an air traffic controller, and then use my ATC skills from my service to become a civilian ATCO?


texts: What's the relation between cabin pressure and altitude?

texts:
Usually, cabin pressure of an airliner is kept at a value corresponding to an altitude of not more than about 2000m.

Now, I heard that before takeoff, the pressure is already increased a little for higher stability of the fuselage. Maybe, this is wrong, but I had another experience:

I was in a 737-800 flying at 11500m. While the aircraft sank on approach for landing, I felt that typical pressure on my ears several times though we still were above 7000m. So, the cabin pressure already changed at that high altitude.

So, how is cabin pressure related to outside pressure during the entire flight?


texts: Why would pilots "call the company" after an aborted takeoff?

texts:
I was skimming through the RealATC videos on YouTube today and watched this one. In it there are two flights taking off from Chicago-Midway (KMDW); Delta flight DAL1328/DL1328 and SouthWest's SWA3828/WN3828. They are each taking off from crossing runways (4R and 31C). For some reason, even though SWA3828 is given clearance to take off, the Delta flight also starts its own rollout.

After the call to abort is given, both aircraft abort takeoff and are able to then safely leave their respective runways in order to taxi back to the proper starting point. One of the aircraft states it will need a few minutes to check for heated brakes. Then both aircraft state they will need to "call company" for some unspecified reason.

Why would both planes need to call company? My guess is to recalculate fuel used to determine if they will have enough fuel to continue the trip. Why else might they need to do so?


texts: What is the benefit of upgrading Flight Management System to version UNS-1Ew?

texts:
I am working in a private airlines. We have some Dash-8 Q400 aircraft in our fleet. Recently a SB has been issued telling us to upgrade the Flight Management System from  UNS-1E to UNS-1Ew.

Can anyone explain what are the advantages for upgrading the Flight Management System from UNS-1E to UNS-1Ew?


texts:
I'm going through the process of designing an RC airplane. I know that probably most calculations on scale models might be non-precise ones, but I'm trying to do it as correct as possible (it's a school project). I was trying to check how much shaft power I would need for the aircraft, so I did an excel table and used some pessimist assumptions in order to check if my 46 cubic inches, which deliveries 1,63HP, had enough power.
These are the aircraft parameters:
Chord= 0,3m
Wingspan = 1,8m
Wing Area= 0,54m2
AR=6
W= 3,7kg (assumed)
Cp = 0,048 (assumed)
Propeller efficiency= 0,6 (assumed)
Air density= 1,225 kg/m3 (Sea Level - where I intend to operate)
I used W = 1/2  *  rho  *  S  *  V2  * CL to identify the required CL for level flight at any given airspeed, then   Cdi = CL2 / (pi * AR *  e)  and using Ri =  1/2  * rho  *  S  *  V2  *  Cdi and
Ri =  1/2  * rho  *  S  *  V2  *  Cdi to find out both resistances I summed them up and multiply them by speed to get power, then I divided that power by propeller efficiency to get the needed shaft power.
For my surprise, the maximum speed that I could achieve with that 1,63HP it's between 39 and 40 m/s or 144km/h (89,4775 MPH), it seems like a lot.
Because of these results, I decided to contact a friend who is into RC Planes, he told me that that engine was actually too little for a 1,8m wingspan plane, it looks like I'm doing something wrong, but I don't know what. L/Ds actually make sense.
This is the link for the excel file


texts: Do aircraft use the majority of their fuel to overcome friction?

texts:
It was asserted (tangentially) in this question that airliners use most of their fuel to overcome frictional losses.

Is that a true statement?

If so, approximately what percentage of fuel is used to overcome friction?
If not, what is the major use of fuel? (Beyond the obvious 'to run the engines'.)


texts: What are the "spur" devices on this U2 pilot's boots?

texts:
From this video on YouTube:

What are those devices and what is their purpose?


texts: Average weight of fuel required to carry 1Kg additional cargo weight per hour

texts:
I'm looking for an average number here, I know there is not one correct answer as there are many parameters to take into account.
Alternatively, I could also use something different, like : how many extra fuel does it take to carry 1kg extra freight from city A to city B.
I guess there is more chance to find empirical data than a perfect answer.

I've found many articles explaining that airlines can save XX€ by removing YY item from the plane, or that it's worth replacing crew books by ipad etc...
And it makes total sense that less weight = less fuel required.

But I've not found any details that would allow me to calculate what I need.

Basically, I want to be able to estimate if it's worth replacing an item by a ligther but more expensive one in an aircraft.

The only thing I found so far is this :
Weight of fuel required to carry 1Kg additional weight per hour : 0,04  Kg

But I've no idea where it comes from, so I'd appreciate if you could confirm and give some detail.

Ultimately, my goal is to get airlines to switch to ligther stuff so they emit less CO2.

Thanks a lot!


texts: What is the meaning of this airport marking?

texts: This mark is identified as a plane control marking and based on an apron surface. What does it mean?


texts: What controllers are used in Airbus/Boeing fly-by-wire systems?

texts: I was wondering, what controllers are used in airbus or Boeing aircraft fly-by-wire systems to control servos? Who manufactures such controllers, or are the systems controlled from flight computer directly?


texts:
I am considering a model wing inside a wind tunnel supported from underneath from its center of mass.
Two load cells can be used, when properly oriented, to measure the lift force and the drag force. How can two load cells be arranged to also measure the pitching moment and specifically the constant aerodynamic moment I discussed in other threads?

Thank you!


texts: How much effect does the nose design of the plane have?

texts:
Boeing 747 nose

Which looks like a goose head

which, for me, much uglier than 737

which has a head similar to

which is of course, much better looking from my point of view. Why are there different designs of the nose for planes by the same manufacturers? What effects do the different designs have?


texts: Where can I find detailed information about ground lighting systems exist in aviation?

texts:
While I'm learning jeppesen charts, I find a list of symbols related to lighting ground facilities, there are a lot of weird abbreviation such as:
Standard ALSF - 1/2, MALSR, SSALR, MALS, SALS, RLLS etc.?
I don't want someone explain all of these to me(because there are a lot of them), but give me source, where I can find them all with depiction and explanation.
Which of these are widely used, and why?


texts: What is the relationship between Angle of Attack and Angle of Incidence?

texts:
The Angle of Incidence (AoI) of most GA planes is 6°. Assuming a plane with an Angle of Incidence of 6 degrees--

How do we calculate pitch attitude if we know the direction of the flight path and the Angle of Attack?  This is essentially a question about whether Angle of Attack is measured in relation to the chord line of the wing, or in relation to the longitudinal axis of the fuselage.

During takeoff, the Angle of Attack (AoA) is often 11° or more.  Is the 11° AoA measured in relation to the chord line of the wing, so that the pitch attitude at takeoff is 11 - 6 = 5 degrees?


texts: Which part of aircraft is contributing the most weight of airplane?

texts:
Which part of the aircraft contributes the highest portion of weight?

Note: we had argument that, wires connecting the avionics systems are the major contributors of aircraft weight. Due to some issues with optical fibre technology this is not been used in aviation yet. So my question arises as mentioned above.


texts: How did pilots avoid thunderstorms and related weather before “reliable” airborne weather radar was introduced on airliners?

texts: How did airline and or mail pilots avoid hazardous weather especially at night before airborne weather radar systems were in use?


texts: What market share does Jet A-1 have in the commercial airline market?

texts:
I know that Jet A-1 is the most widely used fuel in the commercial airline market, but what is its market share in percentage?

Are there any big users of Jet A rather than Jet A-1? And if so, why?


texts: Can carrier-based aircraft takeoff while the carrier is stationary?

texts:
Reading about aircraft carrier operation turns out that carrier operation relies a lot on catapult and carrier itself turns into wind with high rev on propellers. This generate as high wind speed as possible to make a takeoff easier for fixed wing aircraft.

My question is in the absense of carrier's own speed and turning into the wind, would fixed-wing carrier-based aircraft be able to takeoff using catapult and its power alone?


texts: Do cabin evacuation tests include passengers with limited mobility?

texts: When doing the evacuation drills to ensure people can leave the plane in 90 seconds, are they tested with disabled people, ones in wheelchairs or, like myself, people who have difficulties walking and use crutches? I would never be able to jump on the slide or even evacuate in 90 seconds so what would that mean for me? Would I just be left behind?


texts: Is the turning error of a magnetic compass greatest when tuning through South in the Southern Hemisphere?

texts:
Question:

The turning error of a magnetic compass in the Southern Hemisphere is greatest when turning through South.
Is the statement true or false?
And why is this/isn't this the case?


texts: Do I need to get a new AFSP approval if I change my instructor or aircraft?

texts: I plan to remain with the same provider though.


texts: How long is the EASA ATPL theory exam valid?

texts:
I got the JAA CPL and IR and ATPL theory examination in Spain in 2009. They are all expired by now. I didn't renew them until now because I'm flying with the CAAC license and got 3600 hours experience time.
I want to endorse A320 type rating on the EASA license in order to fly in other countrys. They recruiment requirements are EASA CPL(or ATPL) with IR and MEP and (frozen ATPL).

My questions are:

Is the ATPL theory examination expired or is it called the frozen ATPL?
If I hold the valid IR issued by an ICAO member state China,  is the Cross-crediting applicable to RENEWAL of the EASA IR and MEP?


texts: What altitude should you cross DBIGE at on the PALLEY FIVE Departure (SID)?

texts: While at Henderson Executive airport you receive an IFR clearance containing the phraseology "Climb Via the PALLEY FIVE Departure, Coaldale Transition" and you receive no additional altitude assignments from ATC at what altitude should you cross DBIGE at?


texts: What is the airplane type in this formation seen above Eugene, Oregon?

texts: This flight of 2 flew by my house in Eugene, Oregon recently. I assume they're military pilot trainers but I am having trouble coming up with an ID.


texts:
Another post here triggers this question;
Since I was a kid I have read endless articles about how canards are more efficient because both wing-like surfaces are lifting, whereas a tail surface is adding weight.
Yet the most efficient aircraft, gliders, almost never use this layout. A few have, Solitare for instance, but obviously this claim is oversold given the complete dominance of conventional layouts.
So what’s the story here? Is it that they are more efficient but some other effect makes them unsuited for most roles? Or is it simply not true in practice?


texts: Why use Mach number for describing the speed of aircraft?

texts: What does Mach speed mean for describing aircraft speed if the speed of sound changes with temperature?


texts:
I saw this plane at a warbird fly in and would appreciate some assistance identifying it.

I can only tell you what I'm rather sure it's not..

Grumman TBF Avenger

Other US-operated Torpedo Bomber types

Grumman F4F-3 Wildcat

Republic P-47 Thunderbolt

Any ideas?

[EDIT]

Also, is this yellow aircraft the same model, only with a different paint scheme? The nose looks different, but perhaps the cap/cone has been removed, perhaps for maintenance. Otherwise the canopy, wheels, and gear covers look identical.


texts: Is there really a safe for storing secret orders on board a B-52 bomber?

texts:
In the movie Dr. Strangelove or How I Learned to Stop Worrying and Love the Bomb, a safe appears at 4:05 (you can see the sequence here).

Is there really a safe on the B-52? If so, is it normal that bomber planes have a safe on board?


texts: Who was the US military pilot who crashed his plane and was accused of selling it to the Russians?

texts:
There was recently news regarding a story of a former US military pilot who crash landed his plane somewhere in the southwest. He was accused of flying the airplane to Mexico to deliver it to the Russians. The Russians then supposedly dropped him off in the desert from which he walked back to civilization. I believe this was Post WWII & Korea. The pilot lived with the accusation his entire life despite claiming his innocence despite the plane never being found.

The wreckage was just recently found, vindicating the pilot although he had passed away some years ago.

Any help would be appreciated. My google searches came up with many defection stories and red herrings.  I know the story is recent. I just can't find it.


texts: Can I use my FAA Private Pilot (Foreign Based) without a valid EASA SEPL to fly in USA?

texts: Can I fly in the US using my FAA Private Pilot (Foreign Based) based on my EASA PPL without having renewed SEP(L) - it's EASA's class rating for single piston engine airplanes. By flying I mean using my FAA ASEL rating.


texts: How is the flow of air through a NACA submerged inlet determined?

texts:
This question pertains to the design and/or selection of NACA submerged inlets. I am trying to understand what kind of airflow would enter a NACA submerged inlet/scoop and am looking for a good reference to use.

Suppose you have a typical NACA submerged inlet , which has a 2.75 inch diameter hose connection (so an area of 5.94 inch2), and you are flying at 100MPH. How much air actually enters the duct?

I've seen the famous NACA 5i20 Report but can't seem to find the answer or don't understand it fully yet. The report routinely compares the inlet air velocity (Vi) to the free stream velocity (Vo), calling it a ratio "Vi/Vo". It then shows pressure losses for various Vi/Vo ratios. But how do you know what Vi your scoop will get?

I've thought about relating the mass flow entering the duct area (the triangular part) to the mass flow through the inlet, but I'm not sure if that is the most accurate method.


texts: Has there ever been an airliner design involving reducing generator load by installing solar panels?

texts:
Has there ever been a trial/project/design, in which solar panels were incorporated in the design of a commerical airliner (e.g. on the wings), with the aim to reduce fuel consumption by lowering the generator workload?

If no, why not?


texts: What is the minimum weight aircraft in which someone can build logged flight time? Is logging flight hours in an ultralight possible?


texts: How challenging is it to land a plane on a tabletop runway?

texts:
Yesterday(August 7 2020), an Air India Express plane skidded of the runway(Dubai - Kozhikode, IN) and fell almost 30 feet below from the tabletop runway and broke into two pieces. It was also heavily raining and the visibility was low. Unfortunately, 17 people died including the pilot and co-pilot. The pilot was well experienced and had worked in the Indian Air Force. For more info: https://www.msn.com/en-in/news/other/air-india-flight-from-dubai-crashlands-in-kozhikode-both-pilots-among-17-killed/ar-BB17I15z
The runway as I said earlier is a tabletop runway, I heard that these runways create some sort of optical illusion, thus it is challenging to land a plane.


texts: Can passenger airliners hover completely motionless in the air?

texts:
I've seen many stories of this occuring on r/glitch_in_the_matrix (a popular Reddit). People have been seeing big airliners just paused in the air, not moving. Some of them stopped their car and saw that the planes still weren't moving. I thought an airplane would stall if it went too slowly? I'm not a plane expert but can newer passenger planes hover in the air?

Edit - often times, the planes are not high up, but coming in to land or take off. Someone said they were watching planes take off or land, and suddenly a big jet just paused in mid air for 30 seconds before starting to move again.


texts: Can I do a VFR night sightseeing flight in Europe?

texts: I am an American living in the Netherlands, and I recently converted my US PPL to an EASA PPL.  I have significant night flying experience in the US, but I understand that night VFR in Europe is uncommon, and in fact only this year became authorized in NL.  I know a flight plan in required, but I'm unsure whether I can file a plan with departure and destination the same, then just go fly around a bit and return at the specified time.  Or must I have an actual route to a destination that I have to adhere to?


texts:
A Blisk is a bladed-disk, all one monocoque component.

So the blades do not have to be inserted and secured, and they are not removable. No nuts and bolts either.
The downside is that any serious damage to one blade, and the whole blisk must be replaced. The upside, I have heard, is that they save weight. Wikipedia says "efficiency improvements of up to 8% are possible." but I'm not interested in aerodynamic efficiency right now. I'm interested in weight savings.
So the question is, how much weight can you save? Is it really significant? Interested in compressor and turbine blisks and I would not be surprised if the answer varies between them.


texts: I (a hypothetical person) am involved in an activity like laser light shows, model rocket launches, fireworks displays, or construction which I think might be important to pilots. How can I submit this information to the FAA so that they can issue a NOTAM?


texts: Will air traffic control ever ask a plane to not brake hard on a landing?

texts:
In another question, somebody asked why an airplane might not deploy thrust reversers on a landing. One of the answers suggested a few options, including:

  Depending where the gate was, they may simply have wanted use more of the runway to speed up the taxi

It occurred to me that it's not just a matter of a pilot wanting to get to the gate sooner; it could be that ground control wants them to take that last exit (for whatever reason), but air traffic control wants them off the runway quickly so that they can use it for another airplane.

I assume the final decision of how to conduct the landing is the pilot's. But will air traffic control ever ask nicely, "you're going to be taking the last exit, but please don't do the final bit of braking until the end, because we'd like to get another flight taking off right after you land"?


texts: Are there any airports whose budgets are in the public domain?

texts:
Most airports - at least in India - are privately owned. AFAIK, even the ones which are owned and operated by the government (i.e. managed by the Airports Authority of India) do not make any financial numbers known.

Are there any airports whose records are in the public domain (even if they are small island airports)? I'd like to have some idea how things work, even if it's only about a small airport.


texts: Where does the factor 1.3 for Vapp come from?

texts:
The approach speed Vapp is usually given as 1.3 * Vs0, or 1.3 times the stall speed in landing configuration.

Why 1.3? What created a consensus of 1.3 * Vs0 as the generally accepted textbook approach speed?


texts: How does compressibility affect the critical angle of attack?

texts: Why does the critical angle of attack reduce with increasing mach number or What is the effect of compressibility on critical angle of attack?


texts: Are aircraft transferable between companies with different Air Operator Certificates?

texts:
Can Company A use Company B's aircraft if the two companies are not on the same Air Operator Certificate (AOC)? Company A will provide the crew. This would be a transfer of equipment use with no transfer of ownership.

The aircraft in question happens to be a medical emergency helicopter.


texts: Why isn't the application of "carb heat" in initial piston multi-engine failure emergency procedures?

texts:
What is the rationale for not including the application of carb heat in the initial multi-engine airplane's engine failure procedure?

I've recently starting flying light multi-engine airplanes again and have been practicing the engine failure procedures.

I noticed in the POH of the aircraft I'm flying that it doesn't mention applying Carb Heat to the dead engine. So I looked at some other multi-engine POH emergency procedures and noticed that Carb Heat is mentioned sometimes, but in the trouble shooting checklist for restarting, after the initial procedure.

Shouldn't carb heat be applied as soon as possible, while manifold is still hot enough to heat the air to melt any potential carb ice?  Like immediately after pushing everything forward and getting gear and flaps up?

Alternatively, I can also see an argument that before you identify the dead engine, applying carb heat to both engines would decrease some precious power from the currently functioning engine. Are there other reasons for not using carb heat sooner?


texts: How does the A350/380 operate on Variable Frequency AC generators?

texts:
To keep a constant frequency of 400 Hz, most aircraft have a CSD (Constant Speed Drive) associated to the AC generator. On most types (e.g. A320, A330, B737, B747, B777) an Integrated Drive Generator (IDG) is used. This unit is simply a CSD and an oil cooled generator inside the same case that provides this fixed frequency output.

Sometimes we even use a variable-speed constant-frequency (VSCF) generator, that provides AC power at constant frequency using a tap converter.

The A380 and A350 have variable-frequency electrical generator, with no CSD or IDG. How can they work without a fixed AC frequency? If the fixed AC frequency is not needed, why it is needed in all the other aircraft types?


texts: How do I calculate propeller effects on pitching moment?

texts:
I have read somewhere that propellers have an effect on the pitching moment of the aircraft. Having said that, I have a couple of questions.

Is this a significant effect in model aircraft? If so, are there major differences between pusher and tractor configurations?
Finally, how would one calculate this effect?


texts: Is there a good iPhone app for tracking commercial aircraft?

texts: I can see many airplanes circling around to land at KORD. I am wondering if there is a good real-time website or application to track these planes with 30-second accuracy or better. Any ideas?


texts: Do lights on aircraft flash in a specific pattern?

texts:
On a clear night, everyone can spot planes quite easily: they have flashing lights. I have noticed that the pattern seems different for different planes, and tried to find a meaning.

What I saw so far is that they seem to have three lights that flash, two at the wings, one at the tail. Those at the wings flash two times (approximately per second, in quick succession), and that one at the tail flashes only once, along with the first flash of the wing.

Now that explains two patterns I seem to see from further away: Two flashes and one flash. It is probably that I am just not seeing the wings flashing for those where I only see one.

So far so good, but then again sometimes I see planes with more flashing, and those are faster. I had difficulties to count them, but it's at least three, maybe four quick flashes.

Do these different patterns have any meaning? I tried to match up the planes with the flight radar information, but since it is quite crowded around here, I wasn't really able to identify them. But whenever I saw that quick flashing ones, there was a military plane around, is that just coincidence?


texts: Swing-up canopy not shut in high-speed flight, what would happen?

texts: What would happen to a canopy like that on the Eurofighter Typhoon that swings up if it wasn't shut properly and the plane was going at high speeds, would the canopy blow back open?


texts: Is the altimeter setting corrected for temperature?

texts:
In an ATIS or AWOS/ASOS recording, is the reported altimeter setting corrected for temperature?

I think it must be, because on a hot day, the altimeter should still show correct field elevation. If it wasn’t corrected for temperature, then the reported field elevation could be badly wrong on a really hot or really cold day.

(This and other questions describe pressure and density more generally.)


texts: Why do some AFBs have planes parked at 45 degrees to others?

texts: I'm assuming this is just a matter of available space but it seems you could get 4 across all aligned but maybe there is another reason. The image is from McGuire AFB but I've seen this on other AFBs.


texts: Why do these aircraft in long term storage have air and power connections?

texts:
With the Covid-19 crisis many thousands of passenger aircraft have been put in storage. In this  Bloomberg article from July 2019 shows several aircraft in what appears to be storage with covers on engines and cockpit windows. They also appear to be connected to an electrical supply and the engines to some sort of compressor.
Here is a screen shot of the image:
And a link to a large size version of the full image.
Another link to a different photo of stored 737MAX with similar connections.
The Airbus website describes requirements for long term storage, but mentions no connections to air or electricity.
Why are these aircraft provided with air and power?


texts: What Boeing 747 rejected takeoff and runway excursion accident is detailed in this video?

texts:
This video details with an example why not to reject takeoff after $V_1$.

It contains an example of a 747 running off the end of the runway, due to a rejected takeoff past $V_1$ prompted by an engine fire warning. It would appear to be a -200 combi variant with rear cargo door. Faint 'Air France' titles are visible.

What aircraft and flight was this?


texts: Which of the pilots flies when it gets dangerous?

texts:
Who flies when it gets dangerous ?

In other words: Which pilot takes control of a passenger aircraft as Pilot Flying (PF) in an emergency (aircraft upset, loss of control, mechanical failure, etc.) and why ?

the highest-ranking pilot present in the cockpit given his experience
the SIC (second in command), for the reasons quoted below
whoever was PF when the incident began continues flying
or no specific rules, the pilots must make a joint decision

  Just beware that either pilot may be at the controls during a
  particular incident. In fact, while protocols are different [from] carrier to
  carrier, it's not unusual during emergencies or other abnormal
  situations, for the captain to delegate hands-on flying duties to the
  copilot, so that the captain can concentrate on communications,
  troubleshooting, coordinating the checklists, etc. (source)

Case in point:
In the AF447 crash, the captain was not in the cockpit when the incident began. When returning to the cockpit, he did not take over control but sat down behind the 2 First Officers.

Please mention in your answer
- which person (if any) is designated by the regulations, airline rules and best practices
- for what reason
- and whether these rules/recommendations have often been not followed in crashes


texts: How would you get certified for the AgustaWestland AW609 as a rotorcraft pilot or without any previous certification?

texts:
It seems like AgustaWestland might finally get certification for the AW609 in the next couple of years.  Let's say I buy one to transport people to the offshore oil platforms that I hypothetically own.  I'm going to need pilots with a commercial powered-lift rating or possibly an ATP powered-lift, depending on how the aircraft ends up being certified.  Where am I going to find these pilots?

As far as I can tell, the only people who current have FAA powered-lift ratings either converted military ratings from the V-22 Osprey, or are civilian test pilots who worked on the V-22 or AW609 programs.  I guess I could try to hire these pilots, but I will be competing with every other AW609 operator.

Is there a way for rotorcraft pilots to transition to powered-lift?  Is there any way, currently, for a civilian pilot to go from no ratings to commercial powered-lift without getting non-powered-lift ratings first?


texts: How were bullets fired through the propeller in the Focke Wulf 190?

texts:
In WWII there was a plane called the Focke-Wulf Fw 190. It was designed by an engineer called Kurt Tank.

How is it possible that the Fw 190 fires through the propeller from 4 different places as you can see in the picture below? There are two machine guns right in front of the pilot, and one at either side on the wing, close to the body of the plane.


texts: Does ground effect scale 1:1 with wingpsan?

texts:
The rule I have been taught is that ground effect begins within 1 wingspan of the ground.

What is the derivation of this measurement?  Is it actually true, or just an urban-legend/rule-of-thumb style teaching aid?

If it is a valid way to assess where ground effect begins for any given airplane, what limitations does it have?  Do particularly heavy or airplanes with exceptionally long wingspans not fit this rule the same as a smaller more common build of aircraft?


texts: How do you choose a feature to line up on when approaching to land?

texts:
I've been taught that when I'm on final approach to land, I should pick a feature or landmark that's some distance along the extended centre-line, so that when I'm close enough to the ground that I can't properly see the runway edges any more, I can still look forwards and check my heading against this landmark. This is necessary on aircraft without flaps where the nose (the engine cowling) restricts the pilot's view of the runway in the approach.

The view along the runway changes completely from circuit height to runway level, and it's not obvious which features will be visible from less than 100 ft height. At my home aerodrome, it's easy to learn which feature to line up on, because I've seen them all before many times. When I'm landing at a new aerodrome, how can I select a feature to line up and be reasonably confident that it's still visually obvious all the way through the landing?


texts: Does load factor limit actually change with aircraft weight?

texts: Does load factor limit in reality change with aircraft weight? Is it fixed to make certification and operation more simple? Now unloaded aircraft has lower Va speed. This makes sense to keep constant maximum G. But if aircraft can sustain +2.5g at MTOW will anything break if it sustains +3.0g completely empty? As I understand wing bending force will be the same and this should be limiting factor in most aircraft? What else can break? Engines fall off? Tail breaks off? Theoretically possible but can this really happen?


texts: Does ELMS inhibit cabin pressure alarms on the 777, and would the MEC Override Vent be stuck open following an electrical failure?

texts:
I found this article rather interesting, but like most things on the internet, they can be wrong. I couldn't think of a better site to address this question. This user says:

when ELMS takes over power supply it shuts down the Air Cycle Machine (ACM) and the Air Supply Cabin Pressure Controller (ASCPC). Cabin pressure alarms in the cockpit also lose power.

The user follows up with this later on:

In addition to loss of electrical power from the cabin pressurization system electrical smoke in the Avionics Bay or MEC likely tripped open a vent called the MEC Override Vent, which simply allows electrical smoke to be pushed out by cabin air pressure. Once open this vent needs electrical power to close again, so if an electrical failure followed, it would be left limp and open.

I look forward to reading your answers about this, Thank you!


texts: What are the costs of 1 hour flight in modern low-cost airlines?

texts:
Thinking about "low cost" airlines that often tickets of about 40 Euros for 2 flight hours, I was wondering how these companies can cover their costs.

Considering for example EasyJet that fly with Airbus A319 (150 seats), with a unique cost of about 90 million dollars, on a typical 2 hours flight (common average European route) every flight could gain about 6000 Euros in tickets.

I can't understand where is the "gain" considering fuel, crew costs, maintenance etc...

Can you give some references?


texts: Will an aircraft always crash on take-off if de-icing is not performed correctly?

texts:
I recognise the Daily Mail's propensity to adulterate and colour news, but are these user comments about the UAL951 flight on 29 Dec 2014 correct?
The Daily Mail claims:

A United Airlines plane aborted its transatlantic journey and diverted to London today because the flight crew apparently wasn’t satisfied with the de-icing effort it received in Brussels.

But some commenters under the article regard this official reason as concealment or falsehood:

If the de-icing job wasn't good the plane would have crashed on take off. There must be more to this story.
Correct. If the de-icing was not done correctly, the aircraft would have crashed on take-off. Since it was able to fly, climb to cruise altitude and travel several hundred miles, no further de-icing would be required. There was some other unreported reason for the diversion.

Is there any truth in these claims? Will an aircraft crash on take-off if the de-icing is not done correctly?


texts: Do small airfields provide ATIS? If not, what weather reporting service is available?

texts:
Would a very small airfield or airstrip be considered to be a 'terminal' and have Automatic Terminal Information Service (ATIS)? Or would it just have minor weather reporting?

As in, would it make sense to provide ATIS (Automatic 'Terminal' Information Service) for a very minor airstrip? How does an airstrip qualify as being a 'terminal' to require those services?


texts: Can the landing gear be pulled up while the plane is on the ground?

texts:
If a pilot makes a mistake and inadvertently touches the gear up lever, will it actually activate while on the ground and make the plane drop onto its belly?

I suppose that there would be some sensor to prevent this, but I would like clarification on that.


texts: When is this Class D airspace not Class D airspace?

texts:
The Terminal Area Chart (TAC) shows the Class D airspace for Los Angeles International Airport (KLAX) view the full TAC. I have highlighted in green the north and south portions of the Class D airspace. The surface area directly over KLAX airport is Class B airspace.  The note - "See NOTAMs/Supplement for Class D eff hrs" is highlighted in green on the left side with arrows pointing to the two Class D areas (2700 and 2500).

This note suggests that at certain times, these two KLAX Class D areas may not be effective.

The excerpt just below the TAC is from FAA Order 7400.11 - Airspace Designations and Reporting Points and describes the official dimensions of the KLAX Class D airspace and also indicates it (Class D) may not be continuously effective.

The next to last section below is an excerpt from the Chart Supplement Southwest U.S.  (just the pertinent part). The Airspace description shows it is Class B airspace and Class D airspace with "...other times CLASS G"

The final section below is a 2012 FAA Notice (NOTC 3900) announcing the activation of LAX Class D airspace, validating that LAX has Class D airspace north and south of its runways.

My question is: When are these two (2700 msl and 2500 msl) Class D airspace sections (bordered in green) other than Class D?

FAA NOTICE NOTC 3900 - LAX CLASS D Airspace Activation


texts: How is the type of deicing fluid chosen and how much time is required for application?

texts:
From my understanding there are 4 different types of deicing fluids.

How exactly is it determined what type of fluid needs to be used?
How much delay does every type of fluid cause on average?
What is the holdover time for each fluid type?

I am building software for a school project and with the software I want to determine if deicing is needed for a flight.


texts:
If they do then what aircraft are they installed in? This stabilizer is not a T-tail shaped stabilizer.

As you can see there are 2 v-shaped vertical stabilizers with a horizontal stabilizer hanging on the each of the vertical stabilizers. So different from a V tailed. And what advantages would this design have over a t-tail for example?


texts: Does the DA-42 automatically lean to clean fouled spark plugs?

texts: The DA-42 has an automatic run-up method. Specifically, the pilot in command is to hold two buttons (one for each engine) until the run-up is complete. Since the DA-42 has no manual mixture control, does it also automatically lean the mixture when foul spark plugs are detected?


texts: What are the reasons for the end of the dogfight era?

texts: A lot of sources mention that a lot of modern era (5.Gen) fighter jet designs such as the F-35 are focussing on qualities and properties such as stealth, long-range attacks, and versatility just to name a few. It is often brought up that the era of dogfights is over. What was the reason for this shift of desirable qualities in air defense and combat?


texts: How can I tag along on an Atlantic crossing?

texts:
I'm a private pilot based in the US and interested in tagging along on a North Atlantic crossing. I have too little experience to dare to attempt it myself, but I'd love to experience it. Does anyone know if there is a way of making that happen? E.g. are there pilots who take guests along? Or are there legal or insurance impediments?
Many thanks for any information!


texts: What is the average g force experienced on takeoff for an ultralight?

texts: How much g-force is made on an ultralight during take off if its upward velocity of 2m/s?And what's the average g force experienced during takeoff on an ultralight?


texts: Is the standby altimeter required for day VFR flight in a C172 Nav III?

texts: I am very confused about whether the standby altimeter is required for day VFR flight: the KOEL (Kinds of Operations Equipment List) says “0” for day VFR but “1” for day IFR, while the equipment list has it as “R” (required).


texts: How much leverage do commerial pilots have on cruise speed?

texts:
If you fly frequently there are chances you have seen some delays in departure  where you end up waiting in the aircraft sometimes for multiple hours.

Almost every time that happened I remember the PIC announcing something in the lines of We will try to make up for the lost time...

And they manage to do a very good job at that. One of my recent flights was delayed 2 hours on departure but arrived only 1 hour late.

Its quite exciting when they say that, its like wow he/she will speed up! but how much leverage do they have to accomplish that? I'm sure there are commercial as well as regulatory requirements to remain within a range but how broad that range is for general commercial aircraft?

The aerodynamics and engineering part of this problem I know about, I'm mostly interested in the commercial aspect of it. Are the speed ranges set by commercial interests?


texts: Why do flight attendants continue to stand, when the seatbelt sign is on?

texts: Especially during turbulence, I notice that passengers are warned to sit and fasten seatbelts, but flight attendants continue to serve only cold beverages (since the overflow, slosh, spill of hot beverages would be dangerous), stand, walk, and work. Why? It appears unfair for flight attendants to suffer any more risk and danger, even if the turbulence is minor, than passengers.


texts: Why would a commercial flight be landing with a tailwind?

texts:
I just flew into BOS on flight 2539 and we landed either on 22R or 22L even though winds were 19 knots at 010 at the ground and 14 knots at 300 at 3000 feet. There was no change either; the captain had announced northerly winds 30 minutes prior as we approached the destination.

Why would they be landing with a tailwind? Normally flights land at 4L or 4R when winds are like this.


texts: Can the emergency slide be re-used after it has been deployed?

texts:
Can the emergency slides be re-used and re-packed after they have been deployed, assuming no damage is done?

For example, I heard of a case where the slide was accidentally deployed due to opening of the main door when it was "armed". This resulted in the slide partially deploying and landing on the air bridge.


texts: Why do helicopters and airplanes use different headset plugs?

texts:
If the headsets and microphones for general aviation have the same impedance for helicopters and airplanes, then why do they have different connectors on them?

Is it simply to make more money from selling adapters and more headsets?


texts: What dictates the shape of the attitude indicator display on the PFD?

texts:
I notice the atitude indicator displayed in the PFD is either squared-shape or truncated-circle-shaped.

A good example of the square shape is the B747-400, It looks like a square whose corner are a bit rounded:

(Source: airliners.net)

A good example of the circle-shaped is the SAAB2000 or the A340:

(Sources: airliners.net and airliners.net)

They look like a circle whose both right and left sides are truncated to display rules (speed and altitude).

In either case, the information displayed are the same (pitch, bank angle, perhaps flight director,...) and are displayed in a very similar manner (including the colors). Those 2 designs exists for years, so there may not be advantages of one over the other.  Why one is preferred over the other for some manufacturer, and the other one for other manufacturer? What criteria are taken into account when choosing this shape?


texts:
The title is voluntarily the opposite of this question: Why isn´t TOGA thrust always 100% N1 or N2?.
I explain to you with an example: I'm looking to the FCOM of an A320 which states that the "maximum in normal operation N1" is 100%, and "the maximum N1 permitted" is 105%. But then, by looking at the THRUST RATINGS - MAXIMUM TAKEOFF page, where there is the table with altitude on the columns and OAT on the rows, the maximum value of N1 that I can find is 94.5%. Any other N1 table (climb/go around/etc.) has clearly lower values for N1. In A320 this value is enforced by the FADEC and cannot be exceeded.
So what's the point to have a 100%-105% N1 limits if the enforced N1 limit in TOGA can be at maximum 94.5%? Why not just set 100% as the RPM value of 94.5%? Or the 94.5% can be exceeded?
Clarification:
My question is not related to maximum thrust (which it doesn't correspond to maximum N1). I cannot publish the table, however it's the same of this table, but for another engine and for the maximum takeoff mode instead of maximum climb.
I reformulate the question in a more direct way:

Why FCOM says N1 can reach 100% and 105%, if then no N1 mode allows any N1 value over 94.5%?