# All Questions

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### why low cost airlines allow check in much earlier than «full service» companies?

Ryanair allows check-ins 30 days before departure. Easyjet, Wizzair follow suit. British Airways - 24 hours before departure; KLM - 30 hours before departure; Lufthansa - 23 hours before departure. ...
• 111
13 views

### Please describe ram pressure in simple terms

Please someone describe the following sentence in simple words: The Airspeed Indicator is calibrated for 'standard' sea level density, so it will only read TAS if the density of the air through which ...
• 11
100 views

### Are there any/many US airports (with instrument approaches) still without RNAV approaches?

GPS approaches being so trivially easy to establish and maintain, are there any/many US airports with instrument approaches which do not have at least one RNAV approach?
• 2,973
17 views

### Can the torsional strength of a wing be increased by adding more ribs?

I understand increasing the skin thickness is the best way to increase the strength in torsion, but if that is not an option will just adding more ribs work? In a composite wing skin, will adding a ...
• 910
1 vote
26 views

### What is the difference between unserviceable, unusable, and not maintained?

Here are some NOTAMS for a recent flight I was planning: ...
10 views

### How is modal analysis useful in structural design of wings?

In this aviation stackexchange question - Spar-rib-stringer spacing and their thickness in relation to the wingskin thickness , OP mentions modal analysis in relation with stiffness. I would like to ...
• 910
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### Why is the true proportional guidance law considered closed form? What does 'closed form' mean over here and how does it apply to other guidance laws?

Can someone please explain why they refer to the solution as closed-form? From my understanding, the term closed form would imply that the command constant 'c' can only take values from a finite set? ...
1 vote
34 views

### Calclulating lift on airfoil by integrating pressure

Hi, im currently doing a project in highschool, and im looking at the formula in the picture for calculating the lift on an aerofoil by integrating the sum of pressure from the pressure tabs times the ...
39 views

### Locking of the steering system

I’m having some trouble answering the following problem encountered in one of the worksheets for aviation students: The plane shown in the picture stands on the runway. The pilot, while getting off, ...
120 views

### How are the landing lights of the legacy F-18 Hornet seen before landing on the carrier?

The LSO will be able to see the nose gear landing lights to make sure that the aircraft's angle of attack is at $8.1^\circ$ if the aircraft is "on speed". Are these lights (all 3 of them) ...
• 1,805
111 views

### Do aircraft have to be certified specifically for skydiving?

As a skydiver, I have jumped from many different types of aircraft. Most have been specially modified for the sport. Are there requirements outside of the mechanical modifications for an aircraft to ...
• 557
118 views

### Can three pilots accumulate total flight time while training?

Situation: On an aircraft with a flight deck large enough to fit multiple people, three pilots are onboard. 1 PIC in the left seat, and two certified copilots taking turns flying in the right seat for ...
126 views

### Can fuzzy dice help in IMC? [duplicate]

Just had this thought as I’ve read about multiple GA accidents that resulted from unintentional flight into IMC with planes not equipped for it (no attitude indicator), resulting in disorientation and ...
• 101
91 views

### Starstreak Missile system - How do the darts avoid colliding with each other?

There is plenty of detailed info online about how the individual darts fly and manoeuvre but nothing about how they maintain their triangular separation.
59 views

### Do I need a physical print-out of weight & balance calculations onboard

Our flight school taught us to print out some documents relevant to flight preparation and take them onboard the aircraft: This usually included weight & balance...
• 669
1k views

### How exactly is the free shaft part of a gas turbines controlled?

As you can see in the picture, the free turbine still gets the same exhaust gas that the main turbine gets. How can it exactly spin freely from the main turbine? How can the free shaft even stay ...
3k views

### Why is communication between ATC and airliners not also written?

Reading this question: How often does a pilot ask ATC for a repeat? Most modern airliners' cockpits have plenty of digital displays. Why is communication between ATC and pilots not also typed/...
• 3,893
38 views

### How to fix JeppView VFR charts font display

Some of the VFR charts printed by JeppView for Windows incorrectly display various letters on the map. This is especially visible in the NDB/DME designations ("INN", "PAT", "...
• 669
182 views

Airspace around the Swiss village of Davos is restricted as part of the World Economic Forum every year. The amendment to the Austrian AIP instructs pilots who would still like to cross the affected ...
• 669
55 views

### Airline Scheduling Artificial Intelligence Model [closed]

I have built an airline scheduling model where it's able to create a daily flight schedule and clarify the plane for each flight using the genetic algorithm "AI mechanism". Where is the best ...
362 views

### What is the OUTBD PFD setting on the 737 NG MAIN PANEL DUs switch?

Each pilot on a Boeing 737 NG has a five-position switch labeled MAIN PANEL DUs that selects what appears on the two main display unit panels in front of her. Here's a picture of the left pilot's ...
• 506
4k views

### Why is this commercial plane making this manoeuvre?

The plane going in circles above my head for an hour now, what could it be?
• 111
1k views

### What is the piston/leg on the aft wall of the L-1011?

In this response to the APU location on an L-1011, in this image, there appears to be a large piston or leg extended downward along the centerline from the aft wall: Modified: By Reedy (Own work) [CC ...
• 263
488 views

### What is the legally accepted tolerance for altimeter errors under EASA for a VFR flight?

I have a discussion going on with a flying club member. He states that altimeters may have an error margin of up to +/- 200ft. Example: ATC instructs you to fly 1500 feet, you would still stick to ...
• 141
211 views

### If alternator fails and I'm running on battery power, what equipment can I turn off to conserve power?

For a PPL, if the alternator goes out and I'm running on battery power, the typical advice is turn off what you can to conserve power. But what exactly is safe/unsafe, or order in which to turn off ...
• 1,029
74 views

### Where should I look for ferry jobs? [closed]

I'm a 650 hour commercial pilot with ASEL, AMEL, and IR currently working as a CFI. I have experience operating in mountainous terrain, remote areas of the southwest USA, from islands in the Caribbean,...
69 views

### Atmospheric Turbulence Magnitudes

In an aircraft say B737, what will be the effects on altitude and indicated airspeed if the turbulence magnitude between 1.5 and 2?
55 views

### Which airlines are the US flag carrier? [migrated]

I am PhD student and would like participate a conference in United and I have been granted a partial travel grant. But it is given condition that I should travel with a US flag carrier. I don't ...
• 101
279 views

### By what measure was Gander International Airport the "largest" in the 1940s?

According to the Wikipedia article and the original source Gander International Airport had four runways and was the largest airport in the world by 1945. Now, "large" can mean a lot of ...
• 813
6k views

### How often does a pilot ask ATC for a repeat?

How often does it actually happen? Also, is it fine to ask them to slow down if it’s hard to understand, for example, due to a heavy accent?
• 211
119 views

### Do airports commonly have mogas for sale on campus?

The ICON A5 POH gently implies, and other sources outright claim, that its Rotax 120iS prefers a diet of 87 octane mogas, and I've found a couple of sources claiming that while it'll take 100LL, the ...
• 2,246
1 vote
75 views

### What could cause an air data computer interfaced via A429 to only display integer values?

I'm working with a Shadin 2000 air data computer interfaced via ARINC 429 to an Avidyne IFD 550. For some reason, the airspeed tape is flipping between discreet values, and not gradually increasing/...
270 views

### Is a Mode S address changed when an aircraft is sold to another country?

The 24 bit Mode S address is issued by the national CAA where the aircraft is registered. If it is sold to another country, with another CAA, is the Mode S address maintained or is a new one assigned?
197 views

### How do test pilots verify TAS?

This question is about what methods/technology test pilots have at their disposal to verify airspeed indicator calibration during flight-phase testing. A paper published in 2001 by David Rogers ...
• 1,218
180 views

### Can air traffic control see control panel selections (I.e. FCU on A320 or MCP on B737)?

I have flown with a few captains that have told me that air traffic control can see the settings we set on the FCU (or MCP on B737): Is this actually correct? I'm aware that ATC can see what speed, ...
• 309
2k views

### When should I slow to approach speed?

When do I have to slow to approach speed in order to qualify for a particular category? Specifically, if I want/need cat A minima, what is the exact point at which I need to be at 90 kt (or less)? I’d ...
• 25k
109 views

### Why does engine temperature rise upon applying carburetor heat?

When carb heat is applied, the mixture enriches due to hotter and less-dense air mixing with the fuel. But a richer mixture has the side effect of cooling the engine down. So why does carb heat cause ...
• 3
178 views

### Difference between Maintenance planning document(MPD) and Maintenance Manual (AMM)

Could someone explain to a layman, relatively new to Aviation maintenance, the difference between the Maintenance planning document(s) (MPD) and the Maintenance manual (AMM). Is one a subset of the ...
• 21
92 views

### Temperature profile for a boundary layer

So I was reading the textbook today, and I see this picture for the temperature profile through the boundary layer. And I was confused on why the shape looks like this? Should it not look more like ...
1 vote
91 views

### What methods are used to calculate the geometry needed to obtain a bell-shaped lift distribution?

In aerodynamics, what methods do people use to calculate the geometry of a wing (and body) needed to obtain a bell shaped lift distribution? Please go into as much detail as possible for a stack ...
• 23
81 views

### What is the difference between MOCA and OCA?

Can someone explain me the difference between minimum obstacle clearance altitude and obstacle clearance altitude? I read definitions in Doc 8168 but i don't really see the difference. I would be ...
• 1,629
947 views

### Does ADS-B use its own antenna?

In the aircraft we have: ADS-B out/in using 1090ES A/C or Mode S transponder for SSR grounding interrogation. Does the ADS-B out use the same antenna as Mode S or does it use its own antenna?
106 views

### How deep do lift pins go inside the wing in gliders?

In the photograph below, how are the lift pins structurally attached to the ribs and how far does its support structure run inside? Does the discontinuity in the torsional flow in the wing skins pose ...
• 910
30 views

### Engine torque due to Turbofan engines and its effect on aircraft attitude

I know that for turbofan engines there will be Gyroscopic effects while pitching, rolling and yawing maneuvre. But if the aircraft is cruising at an altitude or is simply idling on the ground, what ...
90 views

### How to calculate lift and drag of commerical aircraft in different phases of flight?

What is the best way to mathematically calculate values of lift and drag forces, in different phases of flight: takeoff, climb, cruise, descent, and approach? Edit: I have the idea of calculating the ...
• 1
1 vote
89 views

### Why can't supersonic flow work its way upstream?

I am reading this textbook today. And it described supersonic flow as follows: In a supersonic flow, because the local flow velocity is greater than the speed of sound, disturbances created at some ...
3k views

### What is this old seaplane floating on its wing?

I found this picture today in an old set of drawers that bought at an estate sale over 40 years ago.
1 vote
107 views

### In 1997, what would the likely Paris–Tokyo route be? Generally, where to gain information on historic routes?

Today you would likely via Dubai, or perhaps take one of the long flights say Zurich -> NRT. If I'm not mistaken Dubai came to it's current position in early 2000s, so in the 90s it was not the ...
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160 views

### What is the green arrow on the 777's airspeed tape? Does it exist on other types as well?

Image source: fsnews.eu I found this green arrow on the primary flight display (PFD) of a 777. What does it show? I'm assuming it's for showing acceleration and deceleration but I am not too sure. Is ...