What Is A Level D Simulator?

[AHRS]

Whilst I understand you can perform Base training on a Level D and thus operate your first flight on line training, is it due to the realism in graphic displays or performance realism that defines it?

Which of these (if any ) qualifies as a Level D? (No MsFS answers please.we know about the 767 level D thank you!):

CONCORDE

L1011-200 such as Redifusion (ex Gulf Air)

Trident 3C ex BEA

Hawker 800

Gulfstream GIV

Thanks

[None]

There are a lot of specific requirements for the simulator to be able to demonstrate. This first link below has a table that more simply shows you the comparison between the different types of sims approved by the FAA. I would guess other agencies have similar pamphlets available.

http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/5b7322950dd10f6b862569ba006f60aa/$FILE/Appx1.pdf


http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/5b7322950dd10f6b862569ba006f60aa/$FILE/Signature.pdf

[TFE731]

I am fairly sure the first three on your list are not. As for the last two you need to be more specific some Hawker 800 and G-IV probably are, others will not be.

Your best bet is to ask any sim centre that you are considering using.

[Sl4yer]

Do you know of a working Trident simulator? Not that a 3C existed AFAIK.

Thanks.

[AirRabbit]

Hi AHRS
Whilst I understand you can perform Base training on a Level D and thus operate your first flight on line training, is it due to the realism in graphic displays or performance realism that defines it?
Which of these (if any ) qualifies as a Level D? (No MsFS answers please.we know about the 767 level D thank you!):
CONCORDE
L1011-200 such as Redifusion (ex Gulf Air)
Trident 3C ex BEA
Hawker 800
Gulfstream GIV
If you let me know the reasoning behind your question I would be able to give you a more complete answer; but, I'll start with the following: The type of aircraft has nothing to do with what level of simulator is assigned. Mr None gave you a couple of links that contain some information, but what he provided only scratches the surface. There are specific requirements that have to be met in each case and the two documents you get to in None's links are the basic document and appendix 1 (General Requirements) for the standards used by the US FAA. There are two other appendices in that document; one for objective tests and one for subjective and functional tests. The tests conducted in the simulator are the same tests conducted during the certification flight tests done in the airplane. The results of both tests are then compared to see if the simulator performs and handles within the established tolerances for the specific level of simulator. The higher up the ladder you go, the more tests, and the more detailed the test data has to be. There are other requirements as well - motion systems, visual systems, and sound systems are also more sophisticated and required to be a bit more extensive as you move up the ladder. There is an initial evaluation and then periodic evaluations to be sure that everything continues to operate as it did originally.

Here is another link that will take you to the Home Page for the FAA's National Simulator Program. It is this office that is responsible for establishing the requirements and then actually evaluating each simulator to see if it performs and handles like the airplane it is simulating - in accordance with the requirements. From this page, down the left hand side, you can select additional information about what it takes to evaluate and qualify a full range of Flight Simulation Training Devices.

If you still have additional questions, let me know what it is you're after and I can probably help you out.

http://www.faa.gov/safety/programs_initiatives/aircraft_aviation/nsp/

[AHRS]

OVERSIGHT..IT MIGHT HAVE BEEN A tRIDENT 3B ex BEA which I operated based at a blokes farm in Biggin Hill,costing 60 quid per hour.It was good more of a level C I think.Try it!:)

[AHRS]

Thank you kindly.I had flownal those sims(BAR COMCORDE-WHICH i HAVE ONLY HAD THE PLEASURE OF SAMPLING IN A MsFS) including a 777-200ER and A320-200 at CAE(Which i AM DEAD SURE ARE LEVEL D TYPES).

You could be forgiven for mistaking my line of questioning by thinking i am trying to correlate aic type with level of realism.I know that Level D sims are fairly recent introductionsI SIMPLY WISHED TO KNOW WHAT REFERENCE CATEGORY THOSE SIMS WERE(assuming little variations there in) as there may be variations of categories within the same type of sim depending on the manufacturere and certifier.The HAWKER 800 AND GIV I flew at CAE are glass cockpit versions.I did a detail at Gatwick for the Hawker and I SAW MINUTE DETAILS OF THE AIRPORT ENVIRONS AS I BROKE CLOUD INCLUDING THE PARKING LOT WITH CAR MOVEMENTS!The feel on the runway at touch down was less than realit felt like touching on canvass!The GIV had more impressive visual displays and had an upto dtae landscaped display of the city of Dubai with a the major real estate revelopments in place.tHERE WAS A SIM PROBLEM AND DEGRADED CONTROLS AND ALTHOUGH THE TAXI WAY SIGN BOARDS WERE IN PLACE NOTHING HAPPENNED COLLISION WISE DURING A RUNWAY EXIT EXCURSION!


SORRY FOR THE FOUL TEXT:I HAVE A KEY BOARD THAT IS ESSENTIALLY READY FOR DE-COMMISSIONING.

Another uninteligent question: How the hell do they transport the SIMS TO THE USER'S SITES?ARETHEY DIS ASSEMBLED AND THEN AFTER RE ASSEMBLED ON CLIENT'S SITE?

MY BEST REGARDS (ARE YOU A SIM ENGINEER?)

Your information AS WAS Mr. None's was thoroughly appreciated for its content and I shall refer to the links you provided me with.Thanks indeed to all those who took their time to respond

[AHRS]

did you mean 3c NON EXISTENT IN sIM OR IN AIRCRAFT TYPE VARIATION?I understand 3c were developed and featured improved cockpit ergonomics after the BEA G-PARPI(?) crash on departure at Staines in 1972??China AND PIA I THINK OPERATED these

[Mad (Flt) Scientist]

Just because an aircraft is a recent type does not mean that a sim for that aircraft will be Level D; a sim for an older aircraft can also conceivably be Level D.

As noted above, the Level of the training device is related to the fidelity of the simulation and the degree to which it has been validated, not the base aircraft. You could conceivably have a Level D Sopwith Camel sim if you had the necessary flight test data available and built the sim to the right standards.

Similarly, there are times when it isn't economically justified to qualify a modern sim to the full rigour of Level D. Thus you can have a Level C device, say, for a completely modern aircraft; you can even have a mix of Levels for the same aircraft, if a training centre elects to buy a couple of (expensive) FFS Level D devices, and a couple of (less expensive) fixed base devices qualified to a lower level, using the latter for some parts of their syllabus.

One thing to bear in mind is that there are things which can make the sim better which are not covered by the Level rating; two sims, both to 'Level D', may have rather different graphics quality. Especially if they were originally qualified at different times, where the details of the qualification requirements have changed. The same also applies to aircraft characteristics and motion fidelity. The rules have changed over the years.
(It's much the same as for aircraft certification: what was certifiable to Part 25 20 years ago may not be certifiable today, but both and old and new aircraft are considered to be 'equivalent' Part 25 certified aircraft)

Generally the sims are built at the factory and tested, then disassembled and transported to the site, reassembled there, and extensively tested; it can take many months to get a sim up and running. With a 'repeat' order they may skip the factory assembly stage, and just assume it's going to go together on site, but I suspect that's rarely done.

[AirRabbit]

Thank you kindly.I had flownal those sims(BAR COMCORDE-WHICH i HAVE ONLY HAD THE PLEASURE OF SAMPLING IN A MsFS) including a 777-200ER and A320-200 at CAE(Which i AM DEAD SURE ARE LEVEL D TYPES).

You could be forgiven for mistaking my line of questioning by thinking i am trying to correlate aic type with level of realism.I know that Level D sims are fairly recent introductionsI SIMPLY WISHED TO KNOW WHAT REFERENCE CATEGORY THOSE SIMS WERE(assuming little variations there in) as there may be variations of categories within the same type of sim depending on the manufacturere and certifier.The HAWKER 800 AND GIV I flew at CAE are glass cockpit versions.I did a detail at Gatwick for the Hawker and I SAW MINUTE DETAILS OF THE AIRPORT ENVIRONS AS I BROKE CLOUD INCLUDING THE PARKING LOT WITH CAR MOVEMENTS!The feel on the runway at touch down was less than realit felt like touching on canvass!The GIV had more impressive visual displays and had an upto dtae landscaped display of the city of Dubai with a the major real estate revelopments in place.tHERE WAS A SIM PROBLEM AND DEGRADED CONTROLS AND ALTHOUGH THE TAXI WAY SIGN BOARDS WERE IN PLACE NOTHING HAPPENNED COLLISION WISE DURING A RUNWAY EXIT EXCURSION!

SORRY FOR THE FOUL TEXT:I HAVE A KEY BOARD THAT IS ESSENTIALLY READY FOR DE-COMMISSIONING.

Another uninteligent question: How the hell do they transport the SIMS TO THE USER'S SITES?ARETHEY DIS ASSEMBLED AND THEN AFTER RE ASSEMBLED ON CLIENT'S SITE?

MY BEST REGARDS (ARE YOU A SIM ENGINEER?)

Your information AS WAS Mr. None's was thoroughly appreciated for its content and I shall refer to the links you provided me with.Thanks indeed to all those who took their time to respond

Well, you should know that MSFS is NOT a simulator. It is purposefully designed, built, and sold as a game. Ask Mr. Gates. While some of the features contained in those games are relatively accurate, they are not the same below the surface. Most of the material is gleaned from publicly available sources and, in some cases, a flight crew member may have been paid to report on how a particular system works in the cockpit. However, that is not a “simulation.” That is programming a “cause” and an “effect.” It looks great – and it may be “fun” – but, its not a true “simulation” the way that word is understood in the aviation industry.

I don’t know what you think a “fairly recent introduction” truly is. The first simulator qualified by the FAA for what is termed “zero flight time” training was in 1982 and the first simulator equivalent to Level D was qualified in 1983. That’s 24 years ago – is that recent? I guess in some terms it probably is. But it terms of simulation – devices qualified in 1983 are now considered “dinosaurs.”

Simulators are disassembled at the factory after the purchaser has made a preliminary acceptance of the machine and its programming and it is transported to the facility in which it will be permanently housed. It is reassembled, tested, and checked, and then the regulatory authority is asked to come evaluate it for qualification at a specified level. After all of this is completed, it is then approved for use in a pilot training program.

And, no, I am not a simulator engineer.

[Mad (Flt) Scientist]

While I entirely concur that MSFS isn't a "simulator" in the sense the industry generally uses, there is a little wrinkle to this statement:

However, that is not a “simulation.” That is programming a “cause” and an “effect.” It looks great – and it may be “fun” – but, its not a true “simulation” the way that word is understood in the aviation industry.

Even "real" simulators use "special effects" at times; it's simply not practical to actually provide a physically meaningful model of some things, and they are generally "tuned" as a cause-and-effect. Things like pre-stall buffet fall into that kind of category.

There's always a conflict between the idealised modelling approach and the crude-but-effective one; it's a case of horses for courses, knowing what the tool will be used for.

[AirRabbit]

While I entirely concur that MSFS isn't a "simulator" in the sense the industry generally uses, there is a little wrinkle to this statement:

However, that is not a “simulation.” That is programming a “cause” and an “effect.” It looks great – and it may be “fun” – but, its not a true “simulation” the way that word is understood in the aviation industry.
Even "real" simulators use "special effects" at times; it's simply not practical to actually provide a physically meaningful model of some things, and they are generally "tuned" as a cause-and-effect. Things like pre-stall buffet fall into that kind of category.
There's always a conflict between the idealised modelling approach and the crude-but-effective one; it's a case of horses for courses, knowing what the tool will be used for.
Of course you are correct about some of the lesser systems in a simulator being cause-effect modeling. And, when all that is necessary can be accommodated with this approach - great! However, as I am sure you are aware, many simulator manufacturers and vendor suppliers are often at odds with each other in that the manufacturer of the simulator cannot warranty a "black box" provided by an avionics vendor. When that "black box" has a definitive effect on the interoperability of the aerodynamics of the airplane, it becomes critically important to everyone involved; and, as such, the cause-effect approach for something like the avionics interface with flight control computers is simply inadequate.

Naturally, there are limited circumstances when the fully vetted aerodynamic model, systems models, the avionics model, the controls model, etc. may be loaded into something like a lap-top computer. No argument about the accuracy of the resulting displays - but, in those limited cases, the result is not, and should not be considered to be, "flight training."

My fear, that I was attempting to point out in my earlier response, is that some would enter these forums with knowledge gained on MSFS and pretend to know (perhaps, they even believe that they do know) what it is they are talking about - when what they say cannot possibly be true beyond the capability of MSFS to accurately replicate the systems and avionics functions as well as the performance and handling qualities of the represented aircraft. I think there are just too many folks growing up with computers and being so reliant on them for accurate information, that some who may find their way into aviation may find it awkward or incomplete or even flat wrong to take something learned on a device like MSFS and put it into practice in an airplane - and expect it to work the way it should in that airplane. And, they may not recognize that error until it becomes evident to them at a critical time. A case in point is the bourgeoning "very light jet" market (at least in the US), where, as some of the advertisements luringly beckon, "All you need is a private certificate with an instrument rating..."

Certainly, I'm not saying that MS couldn't generate something more sophisticated than MSFS; but using aircraft and/or vendor flight test data or other validation data to program the MS product wouldn't, I think, allow it to be sold very profitably for anything approaching what the MSFS product sells for in the game aisle of the local computer store.

[Mad (Flt) Scientist]

Don't really disagree. Where the cause-effect model usually breaks down in my experience is when you're trying to cater for abnormal conditions - which, given the degree to which simulators are used to train for failure cases, is quite important. Then the fact that light 'B' is lighting not in response to pressing the switch, but in response to some system operation dependent upon the pressing of the switch becomes vital. The elevators don't move to the position commanded by the column UNLESS the flight control system is working properly, etc.

The "simulated" versus "stimulated" debate for hardware is an interesting one. At first sight it would seem to be self-evident that it's better to have a stimulated piece of hardware, rather than a simulation of it's behaviour. But there are constraints - like transport delays, and assuring that the stimulation is actually valid - which sometimes make simulation a better approach.

[lefthanddownabit]

Here is a very basic list of what Level A, B, C and D means in terms of simulator capability in Europe. FAA is generally similar:

Level A
Complete enclosed flightdeck, all flight crew stations, all systems simulated.
Flight controls force v position tests with tolerances.
Basic motion and visual (night/dusk, limited field of view).
Objective flight tests, some with no tolerance other than "correct trend and magnitude".
Transport delay less then 300 milliseconds.

Level B (all training and checking, except takeoffs and landings)
As Level A, plus
Objective tests all have tolerances applied.

Level C ("zero flight time" for pilots with 1500+ hours in similar class of aircraft)
As Level B, plus
6 axis motion
180 by 40 degree continuous field of view, daylight capable visual.
Transport delay less than 150 milliseconds.
Extra objective tests for contaminated runways, controls dynamics, windshear, motion, etc.

Level D (zero flight time)
As Level C plus
Weather Radar simulated and co-ordinated with visual, TCAS, etc.
Objective sound and vibration tests.

Zero flight time includes base checks, but not the line check.

Some older sims will have "grandfathered" approvals based on the rules used at the time they were first approved. These have a G suffix, e.g. Level CG, but usually same training credits as normal Level.

Level D is an extremely high standard to achieve. By no means all full flight sims are Level C or D.

The age of the original aircraft can affect sim qualification, because if sufficient validation flight test data does not exist then a "special category" approval, based on subjective evaluation, is all you can get. That will be in the form of a letter from the CAA saying what training and checking can be performed. A Trident 3 sim for example could not even be a Level A device under current rules, and there's no chance of anyone flight testing one to get the necessary data now :)

As for MSFS not being a simulation, that's not true, but it is mostly about the eye candy. The MSFS aero model works in just the same way as in a Level D sim, only the data has much less resolution, less complexity, fewer coefficients and is not validated by anybody. The MSFS flight model is very simplified, so no one should expect to learn much about aircraft handling from it. What you can learn is radio navigation, procedures (though not on the included default aircraft), etc.

[AHRS]

Whilst I tend to agree with many things that Air Rabbit proclaims in other threads, I AM NOT SURE WHETHER HE IS QUALIFIED TO MAKE SUCH DEMEANING STATEMENTS ABOUT MSFS.I fully agree with Lefthanddownabit and thank him for highlighting the relevance of MSFS.

I am an avid Pilot and just as avid a simmer pilot.One of the greatest compliments I got from my fellow crew member at an early stage of my career was: You must be a simmer PILOT.i asked why??He replied.we dont tend to fly aeroplanes so damned accurately!

Here is a lesson for correlation.I have been operating MSFS since 1988.I started my flying career since 1990 when i rapidly gained my licenses(7 months) but it wasnt till 2000 when I operated my first commercial flight on a glass cockpit heavy turbo prop.With almost ten years of absence from flying and a meagre 300 hours behind me(I am now a seasoned Pilot), I aced the real Simulator and so was my base(managed Base in only 3hrs) and line training was just as satisfactory.I went to sim after only having read the manuals..and not even jump seated for observation.CBT was done later( shortcomings of the company).The secret...my approach to MSFS and its add ons!BUT YOU HAVE TO APPROACH IT AWITH SERIOUSNESS AS A PROFESSIONAL PILOT.NOT AS A GAMING IDIOT!I was regularly flying (not gaming !) with checklists whenever it was possible to use them.They helped me (and still do) with situational awareness,CRM,SYSTEMS APPRECIATION, INSTRUMENT INTERPRETATION,CROSS CHECK AND CONTROL,R/T WITH ATC OR SUPERVISING PILOT,Airmanship confidence,Flight Planning/thinking,..and yes.a certain amount of Aviation Judgement and technical know how.I PRIME MYSELF BEFORE MY IR and SIM sessions.It is if anything a confidence builder and Panel and instument scan sharpener,and can practice MCC quite effectively...and inexpensively too!

As AN avionics and PERFORMANCE ENGINEER I AM QUITE IMPRESSED WHAT THE MSFS can display and replicate(for those who condemn the use of 'simulator' for these devices).Way to go Micro Soft (and programmers at WILCO and PMDG and the likes of them).yours is a valuable contribution to Aviation and accolades will come to you in time...just keep perfecting your work...we wont mind paying more for it!

TO FURTHER EXPOUND THE VAUE OF MSFS (and I DO REALISE IT IS not A REAL SIMULATOR..for its cost you cant expect it to be!): I have been away from flying pursuing other projects and got my licenses renewed twice with ease (on the strength of practicing on MSFS augmented with relevant book work).I also had the opportunity to fly (with ease...both selected and Managed modes, in normal ops and with Engine failure in IMC of 1km vis)the HS800.GIV,A320-200, and 777-200ER(From Final Cockpit Prep to Engine shut Down)) having had no previous experience on JETS apart from reading a lot on JETS SINCE EARLY 80s(Handling The Big Jets by Sir DP DAVIES being a prime source amongs a myriad of other books and manuals) and practing on MSFS(iT IS NOT SO MUCH THE MSFS THAT I AM COMMENDING HERE BUDDIES..BUT IT IS THE WORTHY TYPE ADD ONS THAT FUNCTION UNDER THE AUSPICIES OF MSFS.MSFS IS A GOOD MOTHER BOARD PLATFORM FOR THE ENVIRONMENT IN WHICH YOU FLY AND 2004 IS ADEQUATE.HAVE YOU SEEN AND TESTED THE CONCORDE OR B747-400 PMDG OR THE 767 LEVEL D AIR RABBIT?I recommend you do so..then check your remarks you had offered me earlier!

The bottom line gents is that if you take two rookie pilots of the same level of experience and expose one of them to MSFS before hand and type him on the MSFS prior to commencing training of type x; you will see for yourself who is going to perform better in every aspect INCLUDING TIME TAKEN TO ABSORB AND PERFORM THE DETAIL TO THE REQUIRED STANDARD!I believe the MSFS with its assortment of add ons can be useful provided that they are approached in a disciplined and serious manner, and with appropriate theory augmented.It is idealy utilised with appropriate CONTROL ACCESORIES ,CHECKLISTS,CHARTS,MANUALS,and under supervision and with appropriate critique like any sim session.It should however be seen for its limitations and if used effectively can actually shave off time required to attain competency on a given type.Before training for a given type, it is however wise to read relevant manuals or observe how the type is flown in line ops or by way of real flight sim.This is to compare notes with the add on type on MSFS SO AS TO DETECT ANY ANOMALIES THAT IT MIGHT HAVE-DUE TO THE LOW COST OF PROVIDING THESE SOFTWARE, QUALITY CONTROL NEEDS TO BE IMPROVED.:oh:

[AHRS]

I dare add......it was a lot easier to fly the real sim compared to the MSFS ADD ONs (due to their ergonomic awkwardness-which you adapt to as you would on a degraded aspect in a cockpit).There is ,however, more copius adrenalin flow from the real sim..but most certainly easier to operate and fly...the transition from the same type on MSFS add on to the real one could catch you open jawed with amazement as how realy simple real flying can be......sims are more awkward than the real aircraft....sort of like transitioning from a light piston aircraft with no automation and co pilot to flying these very stable and automated machines..ofcourse with a disciplined approach.An imminent crash in a real sim(and dare add in a real aircraft) ..are far more alarming than in a MSFS...but your heart beat and BP non the less escalates at a miniature level..IF YOU TAKE IT RATHER SERIOUSLY FELLOWS!

[rbr919]

If we look at AHRS orginal question another way.

Are you just looking at a way of not doing base training in the actual aircraft and therefore not really concerned as to the finer points of simulator levels.

If so basic requirements for ZFT;

A pilot undertaking ZFTT course shall have completed.........on an aeroplane having a MTOM of not less than 10 tonnes or an approved passenger seating configaration of more than 19 passengers.
(a)1500 hours flight time or 250 route sectors if a flight simulator qualified to level CG or interim C if used during the course; or
(b)500 hours of flight time or 100 route sectors if a flight simulator qualified to level DG , interim D or D is used during the course

and the Operator must have JAR OPs approval for ZFT course etc etc etc.

[AHRS]

:ok: Thank you for steering this thread on course!

[mutt]

I can just see it now.......

Please Mr FAA man approve our new training course.... we dont need the $16million Full Flight Simulator (level D), we dont need the $8million Flight Training Device (Level 6), we dont need the Flight Management System Trainer, we dont need the aircraft manufacturer approved Computer Based Training program and we dont need the human interface......

Our new plan is to supply all crew with MSFS plus a couple of add-ons and then let them loose on the aircraft.....

Of course the insurance company agrees :):)

Who was it who said.."a little knowledge is a dangerous thing?"

Mutt

[XPMorten]

Please Mr FAA man approve our new training course.... we dont need the $16million Full Flight Simulator (level D), we dont need the $8million Flight Training Device (Level 6), we dont need the Flight Management System Trainer, we dont need the aircraft manufacturer approved Computer Based Training program and we dont need the human interface......

http://www.x-plane.com/FTD.html
http://www.flightmotion.com/
http://www.flightmotion.com/docs/windsong_faa_cert_press.htm
http://www.flightmotion.com/docs/faa_approval.htm

M

[AirRabbit]

Mad (Flt) Scientist, I agree mostly with your comments – in fact, the only place that I would add (please note, that is “add” NOT “differ”) is that cause-effect models break down when trying to cater for abnormal conditions (just as you said) but they also often break down when the crew operates the systems incorrectly for the situation at hand.

lefthanddownabit, you also are quite correct in your summation of the various levels of simulation … for the JAA (soon-to-be EASA) standards. The US differs slightly in that the Level A simulator also has prescribed tolerances for objective tests, whereas, JAA merely requires CT&M for a majority of cases (…correct trend and magnitude).

As for my statement that “MSFS is not a simulation” being not true … You say, The MSFS aero model works in just the same way as in a Level D sim, only the data has much less resolution, less complexity, fewer coefficients and is not validated by anybody. The MSFS flight model is very simplified, so no one should expect to learn much about aircraft handling from it. What you can learn is radio navigation, procedures (though not on the included default aircraft), etc.
In other words, MSFS is the same, just different. And the only places it’s different are data resolution, complexity, coefficients, and performance and handling to the extent that one shouldn’t expect to learn much about aircraft handling from it. Additionally, it’s not “validated” by anybody. OK. I think that’s probably a bit generous, but, in general, I agree with that. They are the same with those differences. The space shuttle and an RC model airplane are the same – just with some differences.

AHRS, I have elected to keep my identity and my employer’s identity to myself. I don’t want to have my employer feel obligated to defend itself against accusations or comments they might receive because of something I’ve said or implied. Therefore, you, nor anyone else, really knows if I know what I’m talking about or not – that is a given. However, if you choose, you can believe me when I say, I think I am quite qualified to make remarks about aircraft certification, simulation and its production and application, as well as pilot training with and without the use of simulation. I’ll let you read any of my posts here to see if I “appear” to be knowledgeable or not. Your choice. You choose.

Having said all that, while I applaud your efforts and your apparent success in getting through your flight training as you have, and I don’t say this to “pop your balloon,” there are others who have gone through similar flight training scenarios, and have done just as well, and have done so without the “benefit” of years of MSFS operation. So, I would submit that you are probably not quite as uniquely able (even if you do ascribe your abilities largely to MSFS) as you might think.

Also, I would suggest that you re-read my earlier posts. I’m not saying that MSFS doesn’t have any redeeming qualities – just that it does not substitute for the airplane for flight training activities. Any computer-based system, accurately programmed, can do wonders for systems knowledge, procedural steps, sequencing of events, etc. I have described such devices as computerized, animated, and interactive chalkboards – and I certainly don’t use that term in a demeaning manner. In fact I have been on a campaign for a number of years to have manufacturers of certain training equipment (CAE and FlightSafety come to mind immediately) that represent the cockpit of a given aircraft in a series of flat-panel displays (either LCD or Plasma) that are touch sensitive; and are programmed with the identical programming that is found on the legitimate Level C or D simulator – so there are no concerns about interoperability issues between systems, etc. I believe such devices can, and would, allow a pilot to complete training with less time in the aircraft or with less time in the Level C or D simulator – without having to have these new training devices meet any regulatory established standards and be qualified as some lesser level of “flight training device;” the caveat, of course, is that they DO, actually, function correctly. There are other pieces of training equipment that are similar, except they do not have the cockpit mockup with touch-sensitive screens. These cases involve the use of laptop computers (or desktop – dictated by preference), also have systems (often including avionics) programmed rather accurately, and are used for pre-classroom training by several major airlines and training centers. However, here too, the programming is based on manufacturer-supplied data and someone knowledgeable about what such programming should do has verified that programming. These devices are also very effectively used in these cases – but, again, there is no expectation that what is learned is complete and there is no implication that “flight training” has been initiated, let alone, been conducted.

So, because I really don’t know, it would be interesting to find out just who is it that verifies the programming and the interoperability between systems on any version of MSFS? Do you know? Does anyone know? I recognize that Mr. Gates and most of his senior staff at MS have enough clout, certainly enough money, to be able to hire or purchase whatever they want – up to a point. But I know for certain that the development of an accurate aerodynamic model for any given airplane simulation is a tedious endeavor that involves a lot of high-tech equipment and people knowledgeable enough to use it – not to mention access to and use of the appropriate airplane for a rather extended period of time – and the person who owns the airplane has to agree to having things done to his aircraft that are not typical – like drilling holes through the pressure vessel. Then this data is used to modify an aerodynamic program for the structure of the airplane involved, and eventually, a sophisticated, arithmetic representation of the performance and handling qualities of the specific aircraft is developed. When sold to a specific simulator sponsor (at least in the US, and I would assume it is true elsewhere around the globe as well) it is sold with proprietary rights that this aero-program be used ONLY on that single simulator and nothing else. That model, in today’s market, goes for something on the order of $1.5 million a copy. I wonder what that cost would be to MS if the manufacturer knew it was to be loaded onto a platform like MSFS and sold by the millions, if not billions, to interested parties such as yourself for something even like an order of magnitude MORE than you paid for your MSFS version.

Your comment about taking “two rookie pilots” and training them with only one having exposure to MSFS, has already been accomplished – or at least the experiment conducted was close to what you suggest. It was completed several years ago; and, if I’m reading your posts correctly, it was done in your back yard, I believe at the University of Cranfield. The basic experiment was to test the value of “training” on a computer based training device – complete with a computer generated instrument panel and an out-of-the-cockpit visual scene. There were two such computer based devices: one had a stick, rudder pedals, and a throttle; the other used a keyboard and mouse. Three groups of ab initio students were trained equally in ground school. The “control group” went from ground school to the aircraft where they were given a “trials-to-performance” test on 8 tasks commonly expected of private pilots. I don’t remember all the tasks but they were things like turns to headings; accelerate to a stated airspeed and then slow to the original airspeed; climb to an altitude and then descend to the original altitude while maintaining airspeed; interception of an electronic radial; steep turns; etc. The other two groups went to their respective computer-based training devices. Each student was given training on the accomplishment of all the maneuvers that they were to see in the airplane including the 8 which were to be compared. This training was an additional 4 hours per student.

When the trial groups went to the airplane they were given the same “trials-to-performance” tests. The first computer group did much better than the non-computer group did – reaching acceptable performance in about 2/3 of the number of trials taken by the control group. But what was interesting, was that the second computer group did just as well as the first computer group – reaching acceptable performance in about 2/3 of the number of trials taken by the control group. Recall, that the 2nd computer group “flew” the training device with a keyboard and a mouse! What this says to me is that additional training is probably valuable. But what was translated into the airplane was not due to the accuracy or the fidelity of the control method, as they were completely different. So, the additional training must have been realized in additional opportunities to see relationships between bank and pitch, relationships between pitch and airspeed, and so forth. What wasn’t accounted for in this additional experiment was, what would have happened had the “control group” been given an additional 4 hours of training, using a chalkboard, and emphasizing just those relationships? It would be an interesting experiment to try some day.

XPMorten, the links you provided take one to sites sponsored by organizations or persons with whom I am quite familiar. I know and have had extensive conversations with the owner of Fidelity Flight Simulation, Inc. and the developer of the Motus device. In fact, I “flew” the version of this device that was built as a “generic” version of a B-737 a couple of years ago, I think, at a WATS Convention in Montreal. As I recall, the device was not quite ready for sale – as it had only force transducers for rudder pedal use (the pedals did not move, they only recorded the amount of force applied) and, as I recall, the seats did not adjust. I asked the owner why he did not ask the FAA to evaluate the device as a Level 6 FTD and he indicated that it probably would not pass – and, besides, getting it qualified as a “generic” level trainer – at that time a Level 2 FTD – was easier in that no objective tests were required and only a cursory, subjective “flight” was required to “certificate” the line of devices. AND, the authorization issued by the FAA for its use in pilot training was at least as much – likely greater – than if it were qualified to Level 6 FTD standards.

And, the comments posted by mutt were not, I believe, intended to be applied to any type of training outside of those who currently use the normally understood “flight simulators” for substitution of the airplane for training, testing, and checking authorizations. General aviation has always had a lesser level of restriction on training programs – in fact, a Fixed Base Operator, operating within the confines of Part 61 of the FARs does not need to have FAA approval for their programs. The Motus device must be used within a training center approved by the FAA under Part 141 of the FARs – which does require FAA-approval of their training programs. But, none of these schools, to my knowledge anyway, currently use anything like what major training centers or airline training departments use. So your links are really references to “apples and oranges.”

I Truly did not expect to get this amount of comment from my posts … but that is what forums like this are all about.

[mutt]

I AM NOT SURE WHETHER HE IS QUALIFIED TO MAKE SUCH DEMEANING STATEMENTS ABOUT MSFS.

Judging by the answer above, I would say that Air Rabbit is extremely qualified to make demeaning statements about MSFS......

Mutt

[Denti]

I was kinda surprised to see that some Simulators can be changed quite radically on the fly. A few years i was flying a research session in a simulator (http://www.zfb-berlin.de/english/index.html) that is normally certified as class D and used for normal flight crew training for the A330 and A340. In that session the simulator was actually simulating an aircraft that doesn't even exist (A340 with a canard above the forward fuselage and A300 undercarriage, the latter one was just cheaper than the original landing gear model, the canard was the research topic) and in the next simulator session a normal crew was doing its normal recurrent training.

To change that simulator all that was needed was plugging in a notebook and change some aspects of the simulation model while still using those modules that were available from the original simulator. On the link given above you can find further information how they do it.

[AirRabbit]

This type of “research” vehicle is not unusual. For a couple of decades, the US FAA had evaluated and qualified a B-727 simulator located at the NASA Ames facilities at Moffett Field, California. Several years ago, NASA donated that B-727 and purchased a new B-747-400 Level D simulator. This simulator is not used for regular crew training, but, because of the nature of the research, NASA, in conjunction with the FAA, concluded that any research conducted using a simulator that was not maintained in the same working order as any other simulator used for flight crew training would not hold up to the inevitable scrutiny that might follow. Therefore, this particular simulator is held to the same standards and evaluation schedule as any airline or training center simulator.

Along those same lines, the FAA’s own simulator operation at the Mike Monroney Aeronautical Center in Oklahoma City, OK, recently exchanged their aging B-727 simulator for a more modern B-737-800 Level D simulator . This particular simulator, whose main function will be research and development as well, as been acknowledged as likely to be used for the conduct of some training, and is, at present used in the training of FAA inspectors to conduct simulator evaluations. Current and former members of the FAA’s National Simulator Program Staff conduct this training. Just recently, the Aero Center has been given the “green light” to let a new contract for a Level D, Airbus A-330 / A-340 convertible simulator which will be used in the same way as the B-737-800 simulator is currently used.

[lefthanddownabit]

In other words, MSFS is the same, just different. And the only places it’s different are data resolution, complexity, coefficients, and performance and handling to the extent that one shouldn’t expect to learn much about aircraft handling from it. Additionally, it’s not “validated” by anybody. OK. I think that’s probably a bit generous, but, in general, I agree with that. They are the same with those differences. The space shuttle and an RC model airplane are the same – just with some differences.


The method is the same, but the depth and complexity of the simulation is very different of course.

Some people seem to think sims like X-Plane are inherently more realistic because shape determines aerodynamic characteristics. This simulation method is actually no more likely to produce a better result than the data table model. The difference in performance is almost certainly due to the more complex aero model and equations of motion used in X-Plane. MSFS is highly simplified.

You certainly couldn't replace the FFS with MSFS. However some pilots use MSFS plus complex add-on for practise. An airline could use such a desktop trainer in their training programme, would receive no credits for it, but might get better training transfer in the CPT, FBS and FFS sessions.

[AirRabbit]

Hey lefthanddownabit:
Some people seem to think sims like X-Plane are inherently more realistic because shape determines aerodynamic characteristics. This simulation method is actually no more likely to produce a better result than the data table model. The difference in performance is almost certainly due to the more complex aero model and equations of motion used in X-Plane. MSFS is highly simplified.
With the exception of your 2nd and last sentences, your quote here (the underlined part) is the crux of the issue. That is, whether a more accurate and more realistic simulation can be achieved through the use of a complex set equations of motion, modified by coefficients derived directly from flight test of the subject airplane – OR – if one can be provided via a set of look-up tables, populated with what someone thinks (or for that matter, has knee-board data to prove) is representative of the airplane under varying sets of circumstances. Several decades ago the simulation industry went to the aerodynamic model; and quite frankly, I think that is why X-plane has a pretty nice product. Whether or not a COTS X-plane package can be used with flight test derived coefficients (or public domain values in the same areas), and provide the necessary accuracy and realism for a regulator to accept the result as adequate substitution for the airplane, I think remains to be seen – although it probably won’t be terribly long before someone does just exactly that and some regulatory authority somewhere around the world will be confronted with making that decision.

[Mad (Flt) Scientist]

Some people seem to think sims like X-Plane are inherently more realistic because shape determines aerodynamic characteristics.

Personally, I find this hilarious.

When these programs start running full 3D Navier-Stokes solvers, I might - emphasis on MIGHT - given them some credence.

Given a choice between a panel method (or whatever it uses) and REAL flight test data ... it's no contest at all.

[AHRS]

So funny Mut (HO HO HO)......but you apparently missed the whole point.Your sarcasm is a reflection of your tunnel vision perhaps.Curiosly...what have you gained or how have you benefited the thread by your sarcasm?

[AHRS]

I APPLAUD YOUR EXTENSIVE AND IN DEPTH THESIS Mr.AirRabbit.Your knowledge of the subject is indeed commendable.Just want to clear a small misunderstanding.

My statement was intended for your lack of succinct qualifications to demean MSFS as a pre-flight training devise was on the subject of MSFS and not the real simulators.If you wish to verify how the programming is vetted it is best to approach the individual companies that produce the add ons(which is my focus rather than MSFS itself).

This thread was announced with the intent on getting a definition..just DEFINITION of what a Level D simulator was and whether the aircraft on the list I had shown have any fitting to that definition...it was not a trick question or a cryptic one either.

There was no need to inflate my head with your applause for the success of my training....never requested it.I never suggested that the sucess of my training benefitted entirely due to MSFS preparation, rather that its augmentation was very useful(unlike the position that you took on the same) to pre Sim-flight training...PARTICULARLY(I MUST ADD), AFTER A VERY LONG ABSENCE FROM FLYING...SUCH AS ALMOST 10 YEARS!


As I have introduced this thread, I think it would be good to thank every one for the thoughts and commentary this thread has provoked,inspite of the huge divergeance from the original question after your provoking the MSFS factor , despite of my warning against related answers with respect to MSFS in my original question.Some individuals were close to answering the thread more relevantly and I PARTICULARLY COMMEND AND THANK MAD(FLT)SCIENTIST,LEFTHAND DOWN A BIT,and RBR919.Your commentry Air RABBIT was non the less enlighteneing and no doubt, look forward to savouring more from you in future threads

I now consider this thread terminal,unless a clearer textbook DEFINITION of the various levels of Simulators can be offered.

Cheers

AHRS:ok:

[john_tullamarine]

An interesting thread .. but can we all try to keep a goodly sense of humour and good cheer generally ... those who are competent will be recognised by others of competence after a few posts and accorded an appropriate level of professional respect and courtesy ...

If I may add several comments -

(a) some years ago I was involved part time in a particular 737-300 training program.

On a couple of sessions, I was able to take two maintainer colleagues who worked for me in my day job. Neither had pilot licences, as I recall, but both were very knowledge aircraft folk and dreadfully avid flight simmers .. with whichever programs they used.

During the breaks, I put each in the seat, in turn, for a few minutes of push and pull famil and then an ILS. To say that I was more than amazed at the ability of each to drive the box (full flight) to the ILS minima and do a passable landing would be about spot on ... Of course, they would have been all at sea with abnormals and emergencies but the basic speed with which they settled into the seat still causes me to shake my head somewhat ..

(b) I am sure that no-one seeks to equate MSFS and similar software with the high end "real" simulation kits. However, they do have a potentially significant value in, eg, maintaining scan rates and procedural comfort for those whose jobs for the time being don't get them into the real aircraft or real sim ...

Be interesting to see this thread get into the meat of simulator evaluation and certification ... ?

[lefthanddownabit]

Be interesting to see this thread get into the meat of simulator evaluation and certification ... ?

That's a big subject. :) I'd be glad to try and answer questions if you have any.


Whether or not a COTS X-plane package can be used with flight test derived coefficients (or public domain values in the same areas), and provide the necessary accuracy and realism for a regulator to accept the result as adequate substitution for the airplane, I think remains to be seen – although it probably won’t be terribly long before someone does just exactly that and some regulatory authority somewhere around the world will be confronted with making that decision.

You wouldn't gain much from using the X-Plane model, with it's predictive method, because you would then have to try and make it fly to match the flight test data. Easier to do that with traditional aero modelling techniques.

whether a more accurate and more realistic simulation can be achieved through the use of a complex set equations of motion, modified by coefficients derived directly from flight test of the subject airplane – OR – if one can be provided via a set of look-up tables, populated with what someone thinks (or for that matter, has knee-board data to prove) is representative of the airplane under varying sets of circumstances.

You have fallen for the common misconception that MSFS is just look up tables to match observations. There are tables, just as there are in a FFS aero model. These are used to generate some of the coefficients and derivatives. There is a proper, but limited aero model.

Secondly you don't seem to understand aerodynamic modelling. Coefficients are not used to "modify" the equations of motion. Equations of motion come later. First you calculate the aero coefficients and derivatives. From these you calculate forces and moments. Then you insert these values into the EOM.

X-plane allegedly computes coefficients and derivatives from the shape of the 3D model. As the average PC is not yet capable of real time CFD calculations, I suspect this is very simplified and based on published data for aerofoils. Where X-Plane wins over MSFS is that the model they use is more complete, not how they compute the data. Anyway if the aerodynamics of X-Plane is in anyway realistic and non-linear then the only way to do this is with polynomial approximations or function generation (using data tables!).


Several decades ago the simulation industry went to the aerodynamic model; and quite frankly, I think that is why X-plane has a pretty nice product.

Every flight simulation needs an aero model, why does this make X-Plane "nice".

[Bob Lenahan]

What is, or is there, any real difference between the full motion B-727 sim used in 1970 compared to a Level-D sim of today?

[XPMorten]

Every flight simulation needs an aero model, why does this make X-Plane "nice".

It's not that simple. In theory there is nothing wrong with a lookup table
simulator. The problem is that only the aircraft manufacturer has
access to the HUGE amount of data needed to pull it off. Also, these data
will usually be within the envelope. Once outside, things get VERY
complicated. MSFS has a very primitive flightmodel compared to X-Plane.
Austin Meyer (the developer of X-Plane) recently posted the below in reponse
to a review comparing X-Plane to MSFS. It gives you an idea why
the difference is siginificant between the two.

WARNING: Austin is not known for his diplomatic skills :p

http://www.xplanefreeware.net/morten/DOCS/XPvsFS.rtf

Cheers,

M

[lefthanddownabit]

I was really hoping AirRabbit would explain the comment I quoted, never mind.

As you say, Austin Meyer is not very diplomatic, more like one of those infomercial salesmen. :) That style would not go down well this side of the pond.

What Austin Meyer is implying is that his X-Plane is better than any Level D ZFT simulator, which also use lookup tables and which might not consider something or other. Each of his blade elements will probably have a few lookup tables in it's model. You've got to have the data somewhere.

MSFS is well know for more or less ignoring sideslip. Also the lack of many terms means some dynamics are completely missing. The problem is not the so called lookup method, which to the layman sounds inherently unrealistic. It sounds like you take the flight condition, look it up in a table and come out directly with the resulting preformance. In fact all a lookup table is doing is providing a quick and convenient way to model what might be a non-linear, multi-dimensional function.

I did buy a copy of X-Plane once, but soon got fed up with it's user interface, lack of compatibility between versions, constant stream of updates and patches, and the fact that simulation of everything outside the aircraft was extremely basic. Maybe it's better now, but the overall package was disappointing.


What is, or is there, any real difference between the full motion B-727 sim used in 1970 compared to a Level-D sim of today?


Today's Level D simulator has digital sound and vibration simulation which closely match the original aircraft. The visual system, while not up to PC game standards, will be full colour, high capacity, textured, wide angle, with cross-cockpit viewing. The aero model will accurately represent the original aircraft in every degree. Digital flight control loading for highly accurate control feel and response.

A 1970 Boeing 727 FFS would have a basic analogue sound system, buffet cues in all the right places but not closely matching the original in frequencies and amplitudes. If it had a visual at all it would probably be the TV camera and model board type. The aero model would be limited, probably tweaked to achieve certain responses and compromised in other areas. Analogue control loading with good static forces but poor dynamic response.

For basic training purposes, not a great deal of difference then. In terms of overall fidelity and immersion though a huge improvement. All brought about by the FAA's National Simulator Program which successfully standardised and upgraded the expected performance of simulators in the USA, a lead followed worldwide.

[AirRabbit]

Hey lefthanddownabit
Actually, while you may or may not believe it, I do understand aerodynamic modeling. And while I’m not involved in the specifics of aero-modeling every day, I am and have been directly involved on its periphery for the last 20 years. Certainly, you are correct that coefficients are not used to “modify” the equations of motion. However, and, please feel free to correct me if I am in error, once generated and applied they certainly do modify the outcomes of those EOM – and, though I may not have done it very well, that IS the reference I was making.

The largest difference I’ve seen between simulations limited to “look-up tables” is that at times when the simulator was “flown” outside of its flight test validated envelope (i.e., outside of the table values – often the simulator just quit flying in that part of the envelope. You should take a look at the link provided by XPMorten to see someone else's "take" on the limitations of "look-up" tables. For example, a major US airline had an older version of the A300-600 / A310 simulator (and now I don’t remember which cockpit was actually replicated) in which a pitch-up and bank angle combination beyond a certain point would simply “hang” the simulator at that pitch/bank attitude with no control input from the pilots – and, in fact, pitch and/or bank inputs from the pilots were fruitless. In fact, something had to be done to “kick” the computer into a section of the table where values were entered … like pressuring the downside rudder to get the nose to move more toward the horizon. Interestingly, after doing so, the simulator was again “flyable.” There is substantial suspicion that this simulation necessity lead to a very … ah … “interesting” upset event in flight that was looked into by the NTSB. One of the finger points to the guilty culprit was directly toward this particular simulator – and the maneuvering it required – incorrectly “training” the pilots who experienced the upset. Also, please know that my comments here are not based on rumor or innuendo; I have personally “flown” this particular simulator and it DID what I describe here.

On the other hand, more modern simulators use aerodynamic programs that have the ability to compute something for 360 degrees around both the lateral and longitudinal axes. Unfortunately, the only “valid” pitch and bank excursions that are validated as being “like the aircraft,” are those which have flight tested values. In these circumstances, you would not run into a simulator “hanging” at a particular point. The simulator might well perform a reasonable loop or aileron roll because the computer is going to compute something all the way around either axis. Of course, once outside the validated flight envelope NO ONE can attest to the simulator’s performance or handling qualities as being anything even close to the airplane the simulator is replicating. In fact, so adamant are some about this particular point that they are absolutely and vehemently AGAINST the use of simulators for training in “upset recoveries.” As anecdotal evidence, talk to any of the guys who have performed loops in B-747 simulators and aileron rolls in DC-9s and B-727’s. Simulators are wonderful tools when used in the proper manner – and just like being able to drive a nail with pipe wrench – you can do loops in a B-747 simulator – but that is not necessarily the way that particular tool was designed to be used.

Hey john_tullamarine: Your point is very well taken, and has formed the substance for my on-going campaign described in my earlier post:
I have been on a campaign for a number of years to have manufacturers of certain training equipment (CAE and FlightSafety come to mind immediately) that represent the cockpit of a given aircraft in a series of flat-panel displays (either LCD or Plasma) that are touch sensitive; and are programmed with the identical programming that is found on the legitimate Level C or D simulator – so there are no concerns about interoperability issues between systems, etc. I believe such devices can, and would, allow a pilot to complete training with less time in the aircraft or with less time in the Level C or D simulator – without having to have these new training devices meet any regulatory established standards and be qualified as some lesser level of “flight training device;” the caveat, of course, is that they DO, actually, function correctly. There are other pieces of training equipment that are similar, except they do not have the cockpit mockup with touch-sensitive screens. These cases involve the use of laptop computers (or desktop – dictated by preference), also have systems (often including avionics) programmed rather accurately, and are used for pre-classroom training by several major airlines and training centers. However, here too, the programming is based on manufacturer-supplied data and someone knowledgeable about what such programming should do has verified that programming. These devices are also very effectively used in these cases – but, again, there is no expectation that what is learned is complete and there is no implication that “flight training” has been initiated, let alone, been conducted.
The only modification I would make to my quote here, is where I said “I believe such devices can, and would, allow a pilot to complete training with less time in the aircraft or with less time in the Level C or D simulator,” and I probably should have said “…allow a pilot to complete training with the potential of using substantially less time in the aircraft…” The specific amount of time would likely be directly linked to the accuracy of the training device. Personally, I draw the line between what is and should be “flight training” and what could be and likely should be “extended ground training.” The devices I described that are equipped with touch-sensitive screens and can be “flown” only through autoflight systems I believe are easily classed in the “extended ground training” family. Computers equipped with something like a “joy stick” that provides interactive pilot input and results in simulated airplane response are also candidates for this same family. However, when you walk into something that for all the world looks like the cockpit of the airplane and you are able to climb into the seat and function like you would be piloting the airplane – we have now crossed over into the “flight training” segment – and these devices, I believe, must be evaluated against prescribed standards, initially and recurrently, and should have limits placed on them regarding what piloting tasks should be authorized to be conducted here instead of in the actual airplane.

I agree with your musing about having this (or another) thread get into the “meat” of simulator evaluation and certification – although, according to the regulators, they don’t “certificate” simulators … the “qualify” them. And, I too, would be interested in participating in that discussion.

Hi XPMorten: GREAT link! Yes, diplomacy may not be Mr. Meyer’s strong suit, but I wouldn’t want to argue with his accuracy!

[AirRabbit]

Hey AHRS:
My statement was intended for your lack of succinct qualifications to demean MSFS as a pre-flight training devise was on the subject of MSFS and not the real simulators. If you wish to verify how the programming is vetted it is best to approach the individual companies that produce the add ons(which is my focus rather than MSFS itself).

This thread was announced with the intent on getting a definition..just DEFINITION of what a Level D simulator was and whether the aircraft on the list I had shown have any fitting to that definition...it was not a trick question or a cryptic one either.
Sorry. I am not at all sure what you are saying in your first sentence quoted above. I don’t have a desire to learn how MSFS goes about recruiting “add-ons” or how they determine the compatibility of those “add-ons” to the basic program. In my book, MSFS is still MSFS.

I fully recognize your original request was for the “definition – just the definition” of a Level D simulator. Unfortunately, one cannot fully reduce what constitutes a Level D simulator into two or three short sentences. That is why I provided you with the link to the FAA’s National Simulator Program Staff Home Page, from which you can research to your heart’s content – and, after reading sufficiently, you should be able to understand the “definition – just the definition” of a Level D simulator.

For what its worth, I regret that you think I’m “picking” on you or that you feel that I am “trifling” with the successes of your flight training – for I have no desire to do either. What I was pointing out was what appeared to me to be a significant amount of bravado (ego) and even more advice from you in your posts when there simultaneously appeared to be somewhat of an absence of experience to warrant either.

And, here, one more try, is a link that you might find less overwhelming and still informative:
http://www.faa.gov/safety/programs_initiatives/aircraft_aviation/nsp/flight_training/faqs/media/Sim_Levels.doc

[SimWes]

Bob Lenahan
What is, or is there, any real difference between the full motion B-727 sim used in 1970 compared to a Level-D sim of today?
I think that you'll find that in those days the Sims had a 3 or 4 axis motion system. Nowadays they have a 6 axis system (roll, pitch, yaw, heave, surge & sway). Some even have a secondary motion system on top of the primary one to simulate vibrations etc (helicopter ones)
lefthanddownabit
Transport delay less than 150 milliseconds
This means that when the controls are moved in a particular axis (roll, pitch, yaw), the visual sytem as well as the instruments (ADI) must respond within that time. Level B is 300 ms
SW

[Bob Lenahan]

Thanks, SimWes.

[ZFT]

Just to add an extra dimension to the debate.

What are the views on the FFT product currently being promoted and now unbelievably approved by French DGAC, Indian and NZ authorities for just about everything a LD FFS does despite not complying with a raft of requirements of JAR-STD-1A or international equivalents for even a Level B sim, let alone LD? (No motion system, faithful cockpit environment etc).

Is it acceptable for crews to experience their (hopefully) only high speed RTO, OEI or whatever every 6 months or to convert onto type without the ‘benefits’ of a full motion system or a faithful replicant of the flightdeck?

(Having experienced the FFT, it is an excellent training tool that could enhance training programmes quite considerably. However should this type of devise replace an FFS or complement/supplement it?)

[ruddman]

Sorry. I am not at all sure what you are saying in your first sentence quoted above. I don’t have a desire to learn how MSFS goes about recruiting “add-ons” or how they determine the compatibility of those “add-ons” to the basic program. In my book, MSFS is still MSFS.




As an avid aviation fan, and flight sim nerd, I can tell you that the difference between the default a/c on MSFS and an add-on like PMDG's 737 -6,7,8,900 series and the wonderful Level D 767 is light years.

I fully refuse to fly any...er.....sorry....'fly' any default a/c. I'll pay 60-80AUD for an add-on and let me tell ya it makes a difference.

The flight dynamics for one. Planning the descent and approach to use idle as long as possible aint easy. Maybe easier in the real a/c eh! Supposedly use of spoilers below 250kts in the real a/c seem to do little. Which is how the add-ons are modelled. Default a/c? Um.....no.

No FMC in default a/c either. PMDG state of their FMC : " The complexity of mathematics contained in real FMC's has been reproduced here to an extensive degree using actual engineering methods and principles".


Could well be all a wank of course, but I believe it. Also to consider is that the realism can only go as far as the constraints on MSFS anyway.


Know a real pilot who purchased the Level D 767 add-on to practise before using a real 767 sim for the first time in his attemt into an airline here. I later asked him how close it was thinking it would be poles apart. Kinda supprised to learn that the performance was quite close.


Have also met a real 767 F/O who was also very impressed with the add-on. And other pilots I've met have told me that they know new into the airline pilots who use it to get up to scratch on procedures/FMC usage into airports they've never been to before.


Maybe I'm just making excuses to make me feel less nerdy!


Unlike some, I'm also the first to admit that I CANNOT fly a real aircraft because I 'fly' jets well on MSFS. But I'd sure as hell love to test my skill on on real sim. Of course that'll never happen either.


Now lastly, I HAVE flown a real a/c. Actually got up to solo nav flights many years ago when I was learning to fly. Unfortunately, a number of things prevent me from going any further. One of course being $$$.

It'll always be my biggest regret in life. Hey guys, I envy you all like you wouldn't believe. Which is why I view these forums. I love it! I look up at EVERY a/c no mater what. Hell, I even got a job near an airport!


'Flying' the big jets on MSFS will always be the closest I'll ever get to doing actually doing it. So try not to laugh at us nerdy PC 'pilots' too much. Perhaps many are like me and will never get the chance to really do it.



Oh, and I'm not a skinny glasses wearing nerd. I'm actually pretty good looking and have muscles. Just for ya info!

[lefthanddownabit]

What are the views on the FFT product currently being promoted and now unbelievably approved by French DGAC, Indian and NZ authorities for just about everything a LD FFS does despite not complying with a raft of requirements of JAR-STD-1A or international equivalents for even a Level B sim, let alone LD?
The French DGAC is a JAA/EASA member and can't act unilaterally in the way suggested.

The FFT is an FTD/FNPT type trainer, so it meets JAA and FAA requirements for such devices. The idea of these type of devices is to allow the FFS to be used more efficiently, it's pointless to tie an FFS up for procedure training where motion and visual is not required.

It's not a new type of device, it's a new product range for the manufacturer. Their previous FTDs having been more basic.

The manufacturer claims up to 50% of initial and conversion training can be done out of the FFS, which means the FFS is still required for at least 50% of it. A lot of such training is carried out on fixed base trainers now, including in the UK.

They also say it could be used for recurrent training if regulations are changed. That might be a step too far, and I'm not sure the industry would accept that, despite the claims of the experts they cite. It would require a major change to established practice. It is true that sometimes an FFS motion trips, the crew don't notice and continue to "feel" motion cues. However when you lose motion you also lose vibration and buffet, and these can't be "interpreted" from flight displays and situations as they claim.

[ZFT]

The French DGAC is a JAA/EASA member and can't act unilaterally in the way suggested.


I beg to differ - they have.

Additionally MCA plan to perform ALL their recurrent as do Deccan on FFTs.

( I don't disagree with any of your other comments)

[lefthanddownabit]

Hi AirRabbit,
You should take a look at the link provided by XPMorten to see someone else's "take" on the limitations of "look-up" tables.I did, it's bit of a rant by X-Plane's designer. Not exactly an independent view.

However, and, please feel free to correct me if I am in error, once generated and applied they certainly do modify the outcomes of those EOM – and, though I may not have done it very well, that IS the reference I was making

You will always have to calculate aero coefficients in any aero model, good or bad. It is how they are modelled which makes the difference. Without modelling coefficients how would you construct an aero model? Even X-Plane must use them.

For example, a major US airline had an older version of the A300-600 / A310 simulator (and now I don’t remember which cockpit was actually replicated) in which a pitch-up and bank angle combination beyond a certain point would simply “hang” the simulator at that pitch/bank attitude with no control input from the pilots

If this were really true I'd be amazed the airline's FAA POI allowed them to continue to use the sim without correcting the problem, which I have never seen the like of in thirty years in flight simulation.

In fact, what you are refering to is a training scenario for unusual attitudes, not a defect due to problems in a look up table. The sim is driven to the preset unusual attitude selected by the instructor. While going to the attitude pilot inputs are ignored. The pilot controls are then unfrozen and they are expected to recover using the methods they have been trained in. Apparently the simulator in question needed some rudder during recovery, which may have lead the F/O to use rudder primarily.

Whether or not unusual attitude training is completely valid in an FFS is arguable, but if properly constructed it can be useful.

There is no mention in the NTSB report of the simulator itself being suspected as a cause, only the airline's training program which emphasised rudder use at high AOA.
I have personally “flown” this particular simulator and it DID what I describe here.
I'm sure you have, but was there someone on the IOS who maybe decided to throw you an unusual attitude to deal with?

Finally, I'm still puzzled by this statement of yours:

Several decades ago the simulation industry went to the aerodynamic model; and quite frankly, I think that is why X-plane has a pretty nice product.

[john_tullamarine]

'Flying' the big jets on MSFS will always be the closest I'll ever get to doing actually doing it. So try not to laugh at us nerdy PC 'pilots' too much. Perhaps many are like me and will never get the chance to really do it.

If one twists the comment around a little and encompasses the general thrust of the thread, the following observations might be made ..

(a) various levels of simulation all have various levels of "value"

(b) "value" needs to be measured against the technical needs of the user and the desired training (or even entertainment) outcomes sought from the simulation in a cost/benefit style of assessment

(c) at the lower capability end (at a miniscule fraction of the cost of units at the other end of the scale) one finds some procedural value in the maintenance of basic scan patterns and rate and, for instance, I/F letdown procedural skills maintenance

(d) progressively moving up the scale of fidelity (and cost) one finds adequately realistic systems procedural trainers

(e) moving into the higher fidelity (and cost) region one gets progressively closer to the aircraft and can utilise the commercial benefits of ZFT capabilities. (I'm not sure that my Pawnee and Callair endorsements years ago count as ZFT exercises but one could stretch a point, I guess ...)

Do we ever actually get to the "aircraft" in the simulator ? Of course not, although, with enough resources and investment thrown at the model, the approach may have sufficient fidelity to achieve near all reasonable training outcomes

Do we really need to model the aircraft with total fidelity ? Likewise, of course not .. only to the level appropriate and necessary for the training outcomes required. Anything more is into toys for the boys .. even if we all like to get to play with the bigger and shinier gadget in town.

Does that mean that low end simulations are inferior to high end ? Depends on one's point of view .. if the assessment is training outcomes driven it is really a matter of horses for courses .. the optimum through training program will have a range of simulations of different technical validity levels to achieve a desirable mix of cost/benefit.

I could never see the value of "misusing" a FFS on FB for initial ground school basic systems training if a cheap and simple training mockup or CBT package were available to address the same requirement .. a few thousand dollars invested to free up a $20M asset for "serious" training always made good sense to my way of thinking .. and the serious airline driven by the dollar is far more interested in generating the income from selling any excess time

So those who might laugh at nerdy PC pilots miss the point, I suggest .. it all comes back to horses for courses .. whether for Industry training or just entertainment.

[XPMorten]

You will always have to calculate aero coefficients in any aero model, good or bad. It is how they are modelled which makes the difference. Without modelling coefficients how would you construct an aero model? Even X-Plane must use them.

In X-Plane, we design airfoils - like you do in real.
The flight model uses this as a base for it's calculations.

http://www.xplanefreeware.net/morten/DIV/AM.png

Cm, Cd and Cm at different AoA's, Re# etc.
You can use/create real ones (NACA or whatever) or invent your own.
The model will perform accordingly.
There is offcourse 1000's of other variables we enter as well.
Body's are offcourse modelled also.

So, you could say that unlike MSFS, XP has an athmosphere. ANYTHING you put in it will get affected by forces.
This is what makes XP a fantastic "hands-on" simulator. If your main
purpose is flying on AP and pushing buttons, flightmodel is of less
importance. System modeling is, which MSFS is good at.

Cheers,

M

[lefthanddownabit]

So those who might laugh at nerdy PC pilots miss the point, I suggest .. it all comes back to horses for courses.

Exactly right. If you fly an aircraft that has a high fidelity add-on available for use in MSFS (747-400, 737NG, 767-300, ATR72, MD-80 to name a few) it would make a lot of sense to use it as a tool for personal study. One ATR operator I know of was considering using the MSFS ATR as part of their training programme, it's systems simulation being so good.

New pilots now being trained are from the video games generation. They may well have been/still are nerdy PC pilots too. :)

[Mad (Flt) Scientist]

In X-Plane, we design airfoils - like you do in real.
The flight model uses this as a base for it's calculations.

Cm, Cd and Cm at different AoA's, Re# etc.
You can use/create real ones (NACA or whatever) or invent your own.
The model will perform accordingly.
There is offcourse 1000's of other variables we enter as well.
Body's are offcourse modelled also.

So, you could say that unlike MSFS, XP has an athmosphere. ANYTHING you put in it will get affected by forces.


I'm sure that MSFS has an atmospheric model too; that's not a feature that you need to have calculated coefficients for. Our FFS sim models have an atmosphere, and we use lookup tables. It couldn't be otherwise.

And whether the aerodynamic data are in lookup tables is somewhat secondary - the key is what is the BASIS of the aerodynamic data. One could run the CFD-like routines in Xplane to generate lookup tables, and obtain the same degree of fidelity with either the lookup implementation or the "calculation" implementation.

For a "real" simulator we have no choice than to use lookups, because our models are ultimately based upon flight-matched data, not CFD or impirical predictions - we start with the latter, implemented in a tabular format for reasons of code execution and efficiency, then gradually the data are refined in the light of measured flight test responses.

To be frank, I'd be more trusting of sparse, but flight test derived, data, than I would be of wholly predicted data; there are too many times when the "predictions" guys say "but we didn't predict that" for me to be comfortable without some validation.

[AirRabbit]

Hey there lefthanddownabit

For example, a major US airline had an older version of the A300-600 / A310 simulator (and now I don’t remember which cockpit was actually replicated) in which a pitch-up and bank angle combination beyond a certain point would simply “hang” the simulator at that pitch/bank attitude with no control input from the pilots.
If this were really true I'd be amazed the airline's FAA POI allowed them to continue to use the sim without correcting the problem, which I have never seen the like of in thirty years in flight simulation.
Your level of amazement does not surpass my own. However, now you can legitimately say you’ve seen something for the first time in “30 years in flight simulation.” FAA POIs aren’t necessarily responsible for evaluating every aspect of a particular simulator’s programming. And, besides, if someone were sitting in the observer’s seat of a simulator and watch someone “fly” it as I described, and the pilots used the techniques I’ve described, my impression would be that the observer would probably think the exercise had considerable merit. In fact, if YOU were the pilot in that simulator, unless you actually let go of the controls at the appropriate time (to recognize the simulated airplane didn’t react as you would have expected) I think it quite likely that you, also, may have thought the exercise had at least some merit.
In fact, what you are refering to is a training scenario for unusual attitudes, not a defect due to problems in a look up table. The sim is driven to the preset unusual attitude selected by the instructor. While going to the attitude pilot inputs are ignored. The pilot controls are then unfrozen and they are expected to recover using the methods they have been trained in. Apparently the simulator in question needed some rudder during recovery, which may have lead the F/O to use rudder primarily.
Actually, in fact, I am referring to a training simulator that was used for training the recovery from unusual attitudes. Two things about that:
First, we are describing two separate simulator scenarios. There is, or rather I believe it now should be described as “was,” a series of upset recoveries that, as explained to me, contained an external disturbance (e.g., wake turbulence, atmospheric, etc.) being introduced, causing the simulated airplane to respond accordingly. The flight control inputs from the pilot stations were “ramped down” (but not frozen) according to a pre-programmed rate and then “ramped back in” when the aircraft reached a predetermined minimum value of pitch, bank, and/or yaw. I know, for a fact, that this “control issue” (the ramping down and up) was not widely known outside of the airline simulation and/or training departments – and probably not known very widely within those same departments. And there are several training organizations (including airlines) who use that same “technique,” for the same purpose – and, if I’m reading you correctly – one that you do not agree with. If I’m right in my assumption, I am fully, 100%, in agreement with you. I believe that is irresponsible training – leading to a gross misunderstanding of aircraft response to pilot input. I am hoping that these other organizations will recognize the problems this causes and remove that idiocy from their programs – if it still exists.
Second, the simulator to which I am referring was not programmed the way I described above. In this particular machine, the pilot could fly it into the pitch/bank area that ran the computer into an “unknown” zone – and it simply “maintained” what it had until something else happened. Once flying the simulator to that position – you could get out and go to lunch – to return an hour later and find the simulator still in the pitch/bank attitude – waiting for something to happen. What that was, required one of the pilots to use some of the flight controls that were not in an “unknown zone” – like the rudder. Using a small amount of down-wing rudder to move the nose of the simulated airplane more to the horizon, apparently moved the computer back into an area where it found viable information and the simulated airplane regained its responsiveness to pilot input. For quite a while there was an on-going argument about the viability of using rudder input to “help” the airplane recover from a nose high attitude. The pros and cons varied all over the place – but the basic premise was that pilots should not be taught to NOT use flight control inputs, particularly when they were small and coordinated. Unfortunately, the part about not repeating that input and not repeatedly reversing those inputs was not discussed – at this airline, nor any other training organization or airline – to my direct knowledge until after the frightful accident in New York.
Whether or not unusual attitude training is completely valid in an FFS is arguable, but if properly constructed it can be useful.
Generally, I agree with you here. Although, I believe the use of a simulator for training upset recoveries is useful only as long as we stay away from the procedures to be used. As we’ve said here, outside of the flight test validated envelope the performance of the simulator cannot be trusted to be anything like the performance and handling of the airplane in the same situations. However, for someone who has never been in such an attitude (whatever that attitude may be) the ability to see and recognize the relationship of the altimeter, airspeed, ADI, etc. movements in comparison to the “outside view” can be tremendously valuable. Things like, What is the shortest distance to roll to get to the horizon? What is “g-loading?” How many “g’s” can you expect to generate with rather modest movements of the controls (via reference to control force) when in such situations? And so on. Where I think we get into trouble is when we try to “teach” a pilot what to do to recover his/her airplane from such situations.
There is no mention in the NTSB report of the simulator itself being suspected as a cause, only the airline's training program which emphasised rudder use at high AOA.
First, the reference I made was not referring to the American 587 accident out of New York.
Second, the incident I AM referring to was looked into by the NTSB and there were questions about the simulator’s programming. There also were questions from the NTSB when they were investigating the AA587 accident.
Third, I don’t think that anyone could say that the training program you reference “emphasized rudder use at high AOA.” Actually, I think all the statements contained in the AA587 report reflect a training program that called for coordinated use, or minimum use, of the rudder. And, as I recall, statements were obtained from instructors and students having completed that particular course of training.

I have personally “flown” this particular simulator and it DID what I describe here.
I'm sure you have, but was there someone on the IOS who maybe decided to throw you an unusual attitude to deal with?
No, actually, there was not. I could give you the names of the persons who were with me on that simulator flight, but I’d wind up, if not actually disclosing my identity, surely limiting the area of consideration – and, with my apologies, I am not ready to do that.
Finally, I'm still puzzled by this statement of yours:
Several decades ago the simulation industry went to the aerodynamic model; and quite frankly, I think that is why X-plane has a pretty nice product.
What I meant was that a reasonably inexpensive program could be had that used a completely developed aero-program, including the medium through which the “airplane” traveled; the air – and those interested in how aircraft shape affected the aerodynamics could plug those shape changes into the program and see the results. I fully recognize that the Austin Meyer link provided a biased point of view – but that hardly makes what he says less truthful.

[AirRabbit]

Hey john tullamarine:
I generally agree with your hierarchy of simulation “value,” and I go back to my on-going campaign to convince simulator and training device manufacturers, pilots and pilot organizations, as well as regulatory authorities of essentially these same points. Value to the pilot without compromising what it is that the pilot is likely to learn and take into the airplane for application.

What I object to is those who claim to be “pilots” making statements like “If you find you’re too high in the flare, all you have to do is pop some more flaps and push the nose over slightly. You just have to be careful to not land on the nose.” Please note, this is not a “made up” line – but a quote from another forum.

I guess I am acutely aware that we have pilots of all experience levels – including those legitimately desiring to become a pilot one day – and some who like the idea of being able to talk intelligently with “real” pilots when their experience is limited to or is largely on something like MSFS. I worry that if one of the lesser experienced pilots, say just past solo, were to read and believe the statement I quoted above, were to find himself or herself in that situation – too high in the flare – and decided to just “pop” some more flaps and push the nose over – we could see one less participant on the forum – and we’d never know why. Perhaps that is a bit overly sensitive, but I guess that’s a burden I have to live with.

[XPMorten]

To be frank, I'd be more trusting of sparse, but flight test derived, data, than I would be of wholly predicted data; there are too many times when the "predictions" guys say "but we didn't predict that" for me to be comfortable without some validation.

The aircraft modeling in XP is offcourse not only made by
entering known acf data into the sim and hope the flight model does the rest.
In fact, a big portion of the variables are unknown and impossible
to find out in many cases.

So, we use reverse engineering. This is based on real FDR data, manuals
and the good help of professionals like all of you on this site :)
We calculate and calibrate many key variables so we HIT the
real numbers while we still are WITHIN the laws of aerodynamics and the flight model of XP.

Don't worry, no "predictions" guys around here, we usually hit
the numbers we wan't to hit ;)

btw, well said John_T

M

[lefthanddownabit]

XPMorten said:
In X-Plane, we design airfoils - like you do in real.
The flight model uses this as a base for it's calculations.
That's not strictly true. You enter the 2D aerodynamic data (lift, drag, pitching moment) for an aerofoil. X-Plane can't take the aerofoil shape and calculate it's properties from that. Essentially you have a set of data curves for each aerofoil element. Somewhere in X-Plane there will be a lookup table to calculate each coefficient versus AOA for that aerofoil element. So ultimately X-Plane is lookup table based for aerofoils at least.

AirRabbit said:

I fully recognize that the Austin Meyer link provided a biased point of view – but that hardly makes what he says less truthful.

I'm sure he believes it is true. It is really only his opinion, however. He uses too much rhetoric for me, like a politician.

As for the confusion over what incident you were talking about, I hope you can understand why I thought you meant AA587. If you can point me at the NTSB report for the incident you refer to I'd be interested to read it.

The POI does not evaluate the simulator, but has the power to withdraw approval, in this case based on a serious defect not being corrected. Also after an FAA evaluation, the POI still has to authorise the simulator's use for training, so can affect the outcome. The recurrent FAA inspection visits should also pick up on such a defect if it was written up, as it should have been, or if they encounter it themselves. In my experience, the FAA can, and often do, use their power to force operators to update or correct their simulators. However if no one reported it then you can't blame the simulator for not fixing itself.

It's possible an error in the data curves caused the sim to enter a false trim state at this pitch and roll condition which needed some sideslip to exit. However this kind of thing is fixable easily enough.

[AirRabbit]

Hi lefthanddownabit
As for the confusion over what incident you were talking about, I hope you can understand why I thought you meant AA587. If you can point me at the NTSB report for the incident you refer to I'd be interested to read it.
Of course I can understand your reasoning – I was trying not to be overly specific as I generally don’t like airing other people’s laundry (dirty or otherwise) if I have a choice. The accident report (what there is of it) to which I was referring is at the following link:
http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001208X07893&key=1
However, it didn’t get the write up to match anywhere near the level of communications, interviews, on-site simulator looks, etc., that took place during the investigation. Sometimes I get very disappointed with the way some of the activities of the Board are carried out. I hasten to add that generally they are a very fine group of folks performing a superior service for the aviation industry – its just that there are times when politics rears it’s ugly head – and one never knows from what direction it comes.
The POI does not evaluate the simulator, but has the power to withdraw approval, in this case based on a serious defect not being corrected. Also after an FAA evaluation, the POI still has to authorise the simulator's use for training, so can affect the outcome. The recurrent FAA inspection visits should also pick up on such a defect if it was written up, as it should have been, or if they encounter it themselves. In my experience, the FAA can, and often do, use their power to force operators to update or correct their simulators. However if no one reported it then you can't blame the simulator for not fixing itself.
I agree with your statement completely. However, when one does not know that the simulator is programmed incorrectly in some way, sometimes it is extremely difficult to determine that improper programming without flying the precise profile at issue. Most FAA recurrent evaluations call for about 2½ hours of subjective flying and about 1½ hours of objective testing. And normally, things like an evaluation of a particular simulator’s ability to adequately train recovery from unusual attitudes, will be accomplished only if the airplane and simulator manufacturer agree with the programming involved.

However, to the point at issue, as I said earlier if the FAA POI had sat in the simulator and observed one of the profiles that used this particular scenario, it is my opinion that he (or she?) would have thought the exercise had considerable merit. And, importantly, if a pilot were actually flying the simulator (aside from the ridiculous ramping away of control and then ramping back in that control effectiveness later on – I still believe that is negative training!), particularly if he (or she) was flying it the way the briefing told them to fly, that pilot would probably NOT have noticed the tendency of the simulator to achieve the “magic” pitch-bank limit and stay there. This is because the pilot would have applied the down-wing rudder, on cue, to bring the nose down toward the horizon (and the computer back into a known area) and he (or she) would likely never have been aware of what had just happened.

I do not know if this particular circumstance was ever “written up” in the simulator log. Had it been, I’m quite sure the FAA Simulator evaluators would have checked – and, to my knowledge, the FAA never conducted such an evaluation. So, I guess we all can take that for what it’s worth.

[lefthanddownabit]

Hi AirRabbit,

Thanks for the link. Since the flight controls on the A300-600 are irreversible, after AP disconnect any control oscillations would have to come from the flight crew surely? Alternatively, maybe it didn't fully disconnect, so continued to fight the crew's recovery actions.

You are correct about the limited time for recurrent FAA evals. So the onus is on the sim operator to encourage crews to write things up and so get them fixed, rather than just say "the sim always does that" and ignore it. Maintenance engineers cannot fix things they are unaware of.

On the other hand you will always get the pilot or instructor that has a bee in his bonnet about something or other and continually writes something up which is not a defect.

[AirRabbit]

Hi lefthanddownabit

Of course, if there is anything I’ve learned in the years I’ve spent in this industry, it is that “eye witnesses” are not generally the most reliable of witnesses. However, having said that, some of the passengers on board the flight indicated that the bank angle achieved got much more than what was alleged by the flight crew or acknowledged in the “official” report. And, some of the persons with whom the flight crew allegedly spoke immediately after landing, originally indicated that the story the crew gave at first was somewhat different than the one they gave later to the investigators. Again, surely speculative; but interesting nonetheless. And, lest someone believe I’m out to “get” the crew … I am not! I just want the training exposure experienced to focus on the skills learned and reinforced to be the same skills that are necessary and proper to use when in flight.

Actually, I had not considered your theory of potentially incomplete A/P disconnect; an interesting point I do admit. But, I do know what simulator was used for the most recent training of this crew; and I do know what was taught regarding the use of the rudder in that simulator (and now I know why) – and some of the stories told about the initial discussions immediately after the incident/accident match suspiciously closely to what would likely have happened had the crew followed the techniques used in the simulator.

[lefthanddownabit]

Hi AirRabbit

Presumably the angles mentioned in the report are from the FDR. To most people in the cabin 50 degrees bank will feel more like 90. Even the flight crew might initially overestimate the max bank angle they reached.

You're in a much better position to judge what really went on than me of course. I just enjoy technical debate. :)

I would certainly expect this aero model to be valid for all AOA's up to stick shake, but if you have significant sideslip as well, even at 7 degrees alpha, no commercial aircraft aero model is going to stand up very well. The 737 aero model had to be revised for just that reason after the rudder hardover incidents.

[XPMorten]

Somewhere in X-Plane there will be a lookup table to calculate each coefficient versus AOA for that aerofoil element. So ultimately X-Plane is lookup table based for aerofoils at least.

The airfoil designer decides the Coeffs vs AoA for each airfoil
section, not the sim.

Anyway, you are missing the point. Lets take an example;
Lets say you go for a 1 hour complete flight. Thats 3600 secs.
Lets say your simulation rate is atleast 30 frames/sec.

In other words, if you use a lookup table and want to hit book values
at all times, you will need 100.000 sets of data since WEIGHT changes constantly, also in cruise.
If you do the EXACT same flight, only with a small change in
Takeoff weight, you will need another 100.000 sets.

Now imagine if you do cross control maneuvres, stalls, engine cuts etc etc. you will need dusins of tables for each frame.

I can assure you that a 40kb .air file in MSFS is not capable handling this. A $15 million Boeing sim yes, maybe.. .

Cheers,

M

[lefthanddownabit]

XPMorten said:

In other words, if you use a lookup table and want to hit book values
at all times, you will need 100.000 sets of data since WEIGHT changes constantly, also in cruise.
If you do the EXACT same flight, only with a small change in
Takeoff weight, you will need another 100.000 sets.

You have completely misunderstood how lookup tables work. There are no tables of performance versus weight, or anything else. What you have is this:

For each aero coefficient, there will be a lookup (or function) table. This is analogous to the data you enter for the aerofoil in X-Plane. On an FFS this might be two or three dimensional (say a function of AOA, Mach and Sideslip). In MSFS they are all one dimensional, e.g. CL v AOA. Some may actually be linear equations for simplicity. So MSFS will compute the lift coefficient for the current AOA. Other lift effects are added (due to flap, gear, spoilers, etc) then CL is converted to Lift by multiplying by (0.5*rho*V^2*S), yes MSFS knows about this too! The same applies to all the other coefficients in other axes (I doubt MSFS considers sideforce, but it will have CD, CM, Cl and CN.

These forces and moments are integrated in the EOM (which is, I concede, simplified compared to X-Plane, and the only real difference between the two sims). The effect of changing weight (and anything else) will be automatically considered by this model, in exactly the same way as X-Plane.

There are some global tuning factors in the aircraft.cfg file, which also sets values like stall speed, Mmo, etc. Note, the aircraft.cfg file does not set aerodynamic stall speed, the value is just to trigger the stall warning message. Tuning factors make the designers job easier, but don't detract from the validity of the model.

An FFS has CL, for example, broken down into many contributing functions, whereas MSFS will probably only have the basic lift curve slope, but that is just like X-Plane too.

Even X-Plane only considers one dimensional functions for its aerofoils (CL, CD and CM versus AOA). You can have two functions (one for high Reynolds No, one for low) with linear interpolation in between but that is still quite crude, especially for high speed aircraft.

Reading the X-Plane forums I came across references to MSFS using a "behavioural" model, which ties in with your thoughts on how lookup tables work. It is an entirely false description of how the MSFS aero model works.

[XPMorten]

You are right, I was way to optimistic about how MSFS works ;)

Even X-Plane only considers one dimensional functions for its aerofoils (CL, CD and CM versus AOA). You can have two functions (one for high Reynolds No, one for low) with linear interpolation in between but that is still quite crude, especially for high speed aircraft.

True, but you are forgetting that we in X-Plane CAN build a wing out
of up to 12 wing sections with 4 airfoils on each. Each section
can consist of 10 stations - 120 total - with different incidence on all
of them. We also have airfoils on Stabs, props and pylons.
It also models downwash on the tail in e.g a slip which is sort
of 3D.

XP is not perfect, but it's improving every day.

Cheers,

M

[lefthanddownabit]

True, but you are forgetting that we in X-Plane CAN build a wing out
of up to 12 wing sections with 4 airfoils on each. Each section
can consist of 10 stations - 120 total - with different incidence on all
of them. We also have airfoils on Stabs, props and pylons.

I wasn't forgetting that, and I recognise that makes for a powerful engineering based sim design tool. But as I say, you won't find that sort of model breakdown even on a Level D FFS, which generally use "whole aircraft" data. That doesn't make the FFS less accurate, but it's only as good as the manufacturer's data that goes into it.

I'm not pro MSFS, or anti X-Plane, there's room for both, depending on what you want out of the simulator.

One question for you, purely out of interest: how does X-Plane represent the aerodynamics non-aerofoils like the fuselage, for example?

[XPMorten]

how does X-Plane represent the aerodynamics non-aerofoils like the fuselage, for example?

A couple of years ago we discovered a huge error on the fuselage/body lift model.
Actually we managed to get a WINGLESS B777 to stay in the air at
an AoA of about 15 deg about FL100! After numerous atempts to
get Austin to change the model we ran out of arguments. :ugh:

Then, finally, we accidentally got in contact with the CHIEF DIRECTOR of Aerodynamics
at NASA Dreyden (!). Austin finally backed down and the modell was changed :ok: A rocket body has pretty much the same issues as a fuselage.

Don't know all the details, but we know it's based on length and frontal area. Possibly also the 3D shape to some extent, at least for
supersonic flight. Lift, drag and downwash is calculated. Parasite drag is entered by the designer since this will vary from design to design.

Cheers,

M