In a recent flight on an Airbus A380 I noticed that its ailerons are split into three segments which move independently.
What advantages does this design have? Do other aircraft have split ailerons (or other control surfaces)?
I don't know the specific rationale in this case, but if you think about mechanical advantage, the farther an aileron is out from the center of gravity, the more roll effect will have on the airplane. You'll notice in the image that the outer aileron is deflected less than the inner aileron, even though they are probably producing roughly the same roll moment.
A benefit I see is that it undoubtedly reduces wing-loading at the far end of the wings, and therefore reduces stress/flex on the wing during turns. This could be very important for an aircraft as massive and heavy as an A380, but less important for smaller aircraft where the wing-load is naturally less.
There are three main reasons for having multiple ailerons per wing on large aircraft:
On a large aircraft, at high speeds the material of the aileron can be flexed so much as to nullify or even reverse the direction of change of lift, which causes significant issues. The further out on the wing an aileron is, the more it is subject to these forces. For high-speed aircraft, this necessitates an outboard/inboard aileron, with the outboard being locked out at a certain speed limit. On the Airbus A380, the downwards motion of the outward aileron is locked out at 240 KIAS, and upward motion at 300 KIAS.
Another issue is that on most large aircraft, it is simply infeasible to have cables running through the aircraft, requiring the use of hydraulics. Having ailerons split would allow for more redundancy of system failures, allowing more controllability in these failure conditions.
Building on what Bret Copeland has already discussed in his answer, multiple ailerons can be used by fly-by-wire computers to flex the aircraft's wings in a specific manner to allow for less loading on the wing during cruise (counteracts the wing's natural tendency to flex upwards), as well as allowing for dynamic turbulence alleviation.
One of the examples of using this is in Airbus's Safety First magazine (July 2012), where they use the flexibility of having three ailerons to tune out lateral accelerations in the rear of the aircraft changing the gains of each of the controls. By being able to move the centre aileron a fraction after the inner aileron, they managed to avoid these initial shifts during flight testing of the A380.
The majority of airliners have multiple ailerons, however in some instances (such as the Airbus A310), there is no outboard aileron -- this function is replaced by spoilers.
Another example of using computers on multiple ailerons is the Boeing 747-8, with the use of the outboard aileron to fix issues relating to the development of flutter in certain extremes of the flight envelope, called the Outboard Aileron Modal Suppression (OAMS) system.
In a recent flight on an Airbus A380 I noticed that its ailerons are split into three segments which move independently. What advantages does this design have? Do other aircraft have split ailerons (or other control surfaces)?
, probably the first of the day. Having done walk-arounds for a Cherokee, I would like to think that I wouldn't allow such an event to happen on a small plane. On the other hand, I realize that it would be impossible to do a thorough inspection on, say, an Airbus A380. What is a typical preflight inspection checklist for a Dash 8 or similar plane? Would it have included, for example, a visual inspection of the flaps that would have allowed the snake to have been spotted?
translate to a deflection of the surfaces, mimicking the "old" mechanical control setup. It is my understanding that this is the design choice of Boeing in its new aircrafts. I do not wish to discuss... or Airbus/Boeing certified pilots or even pure civil/(former) military pilots. Does any of you have any reference? ...Provided an aircraft with a fly-by-wire system, there are basically two possible choices when it comes deciding how to let the pilots interface with it: rate control / attitude hold: a deflection
On the sidesticks of Airbus aircraft, there is a Priority Takeover button. Wikipedia has this to say: In typical Airbus side-stick implementations, the sticks are independent. The plane's computer either aggregates multiple inputs or a pilot can press a "priority button" to lock out inputs from the other side-stick. On US flight 1549, the CVR transcript shows that Sully hit the Priority T/O button, after the co-pilot (Skiles) handed over control of the aircraft: 15:27:23.2 - Sully: My aircraft. 15:27:24.0 - Skiles: Your aircraft. 15:27:26.5 - FWC: Priority left. I'm
I just finished reading an interesting post where the author suggests that the missing Malaysian Airlines flight 370 could have 'hidden' under the cover of Singapore Airlines flight 68 to fly to a covert airstrip. I've read multiple thrillers where submarines have hidden behind the acoustic signal of large cargo vessels to mask their sound over sonar arrays, and this (at least in the book... there might be some radio interference or static from such as large aircraft behind them? Are there every any issues when refueling aircraft do this sort of thing? What is the resolution of radar? Would one
I have recently been using a mobile app to track flights, which is really cool. I live in the rural heartland of America, so it's an event for me to see an A380 actually flying. Every once and a while a squawk 7700 alert will come up, which I understand is the emergency transponder code. There are more, such as 7600 and 7500, which I find are less common. My question is, is there a way to do some post-mortem followup as to why the aircraft squawked the code? Is this public information that can be found by some agency such as the NTSB?
Watching a video on YouTube of an A340-600 takeoff, I noticed that it has at least two exterior cameras — one for lining up the nosewheel, and the other on the tailfin: After the NTSB recommended the use of exterior cameras in 2012, I'm wondering how widespread these are? Which models of Airbus aircraft have them? Do any Boeings? For bonus points, do these record or are they realtime-only?
which periodically transmitted maintenance data to a remote Airbus location in Paris to alert ground crews of possible maintenance issues with inbound aircraft. Given that Airbus already uses similar technology for maintenance data (and I think I recall hearing Boeing does too), I was wondering if either Airbus, Boeing, or the FAA, plan to facilitate or mandate that the CVR and FDR record to the cloud or a remote location either in lieu of or in addition to the physical devices installed in commercial aircraft. I would think this would be an accident investigator's dream come true
I have been using an Android app to track flights. Their information is pulled from their own proprietary database, and some (with 5 minute delay) from the FAA. I was thinking about making an app that would do this as well by pulling from multiple data sources. What are some good APIs, either paid or free, that gives you near realtime data of flying aircraft?
I know that historically pilots used to trim an aircraft to relieve continuous application of force during climb/cruise/descent, and at that trim tabs existed on control surfaces (elevator, ailerons... reduced on the pilot. Does trimming do anything other than reduce pilot workload? Also: Do modern aircraft still follow this concept of trim to reduce pilot's continuous force on the flight controls? Apart from pilot workload and fuel efficiency (I know that trimming an aircraft can produce drag), what other benefits does trim offer? Without trim tabs, how is trimming accomplished?