Engineering design Vs Pilots perception

[Nigd3]

I posted this on another forum and didn't receive a huge number of posts. Maybe it was the wrong forum, or maybe just a crap post but I thought I would try it again on here anyway.



I would be interesed to know what equipments, display, switches, indications, levers etc etc, would you really like to change in the current aircraft you fly, to make them more intuitive to use.
It doesn't matter how large or small the change but obviously your reasons why you think the current implementation should be improved and the solution you determine best.

Two of my favorites are the following:

- Inside-out Vs the Outside-In ADI. Some in depth testing has shown that the "Russian standard" Outside-In view ADi is actually more intuitive to use for recovering from unusual attitudes than the traditional Inside-Out view ADI of the west.

- The story regarding the wing sweep lever for the F-111, in that it was originally designed with the function of lever forward-wings sweep forward, lever back-wings sweep back, perfect one to one mapping, engineers logical solution. However pilots perception is lever forward=go faster, lever back=go slower, along with the other controls in the cockpit that meant something went faster if you pushed it forward and vice versa. So as the pilot wanted to slow down for landing, the wing sweep lever was moved aft and the wings swept back, which was obviously not very nice. The wing sweep lever was subsequently re-designed to stop any potential confusion for the pilots.

Cheers for any info.

[FlightTester]

Regardless of which controls etc it'd be nice to change to make them more intuitive, you'll have to make sure that you're not going to run foul of the following:

FAR 25.777

FAR Part 25 Sec. 25.777 effective as of 12/01/1978 (http://www.airweb.faa.gov/REGULATORY_AND_GUIDANCE_LIBRARY/RGFAR.NSF/0/F6F1CFA90A5388C28525667200511994?OpenDocument)

FAR 25.779

FAR Part 25 Sec. 25.779 effective as of 08/20/1990 (http://www.airweb.faa.gov/REGULATORY_AND_GUIDANCE_LIBRARY/RGFAR.NSF/0/6D1D546D1481110E85256672005113D4?OpenDocument)

FAR 25.781

FAR Part 25 Sec. 25.781 effective as of 08/20/1990 (http://www.airweb.faa.gov/REGULATORY_AND_GUIDANCE_LIBRARY/RGFAR.NSF/0/2E2280DAB6A2143585256672005114C3?OpenDocument)

[John Farley]

You do not give details of the research you quote re Russian vs Western attitude displays although I happen to agree with your views IF (and it is a huge if) the pilot has little or no experience of using western displays.

Regardless of which is the better display the task of changing all the western world pilots over to such a different way of thinking would be almost unthinkable. Likely acceptance of such a change would surely depend on the experience level and age of the candidate pilot. Unlearning something SO fundamental would be a huge issue.

Indeed I even wonder how many people used to the western way would even understand your description of the two methods of displaying attitude!

[FlightTester]

In a bizzarre turnabout our UA "trainer" is an L-39 Albatross with a Russian style ADI. So we're practicing UA escape manoeuvers for the Western aircraft we certify in an aircraft equipped with Russian instruments.

Latterly, with everything going glass it's fairly intuitive to follow the big pointy chevron that appears at +30 and -20 degrees of pitch.

Cheers

FT

[Bullethead]

"Unlearning something SO fundamental would be a huge issue."

I dunno, thousands of pilots have converted from Boeing to Airbus! :}

I'm not telling which side I'm on. :p

Regards,
BH.

[Nigd3]

JF - I think one of the sources of information was Roscoe 1968, that detailed results that come down on the side of the Outside-In ADI.
As an honest question, do you think it would really take a huge amount of retraining to fly on an O-I ADI rather than an I-O ADI?
The one aspect that could create a problem in the future for the O-I ADI, is if it was installed in an aircraft with a HUD that obviously presents a display format of I-O. Of course you can then also progress onto the presentation of the roll index as another discussion point for the best format.

On a different note, does the general preference of aircraft reference symbol change when you are manually flying an aircraft, compared to when the flight director is up on the display? Most people that I have spoken to prefer the gull wing reference for manual flying, as it gives a better roll perception and the single cue "chevron" for FD (put the notch in the crotch). We have an aircraft (FAR 23) that will change the PFD aircraft reference symbol based on engagement of the FD or not. This was also done as the SFD has ILS indications in a "gull wing" dual cue format and there would have been potential confusion if the PFD had a dual cue FD.

Thanks

Nigd3

[ianp]

Hi Nigd3,
Sounds simple doesnt it; what and how would you change stuff in your cockpit? Don't think it is quite that simple, firstly;

Cockpit needs to be considered as a whole, just chucking in a different AI, no matter how intuitive it is, will only work if it complements all the other aspects of the cockpit. Lighting, FoV, glare, compatibility with data sources, redundancy and loads of other guff.

Secondly;

What are you going to use the ac for? If the role is to remain unchanged this makes things simpler but if the cockpit works as is why change it? If you are upgrading cockpit dispalys for an enhanced or completely new role then this needs to a critical part of your assessment.

Whatever you are looking for good luck but if it is an answer to the skypointer vs earthpointer argument you will never please everybody :ok:

[Rich Lee]

Bullethead does make an excellent point; most pilots do not find it very difficult to transition from new technology to old technology. It is, however, very difficult to reach pilot consensus about various design options, as most the design engineers will readily attest. There are differences of opinion between young and old pilots, civil and military pilots, and line pilot versus pilots in management. There are differences of opinion between design authority standards (e.g. French and US) and government regulations. There are often several very good solutions to the same design question. Engineers for the most part would prefer to search for the most elegant solution, but are often required to do so within externally imposed cost, schedule, and regulatory constraints.

O-I ADI rather than an I-O ADI? The market is always the final arbitrator. One design, often regardless of merit, will be selected over the other by the market. The market might be forced to make a selection because a government imposes a design, or because of cost, or because of senior management fiat; but the design or product is rarely selected because it is the most elegant solution.

[Nigd3]

Hi ianp

Simple, definately not. I've found that total upgrades field the least "gotchas" than the "simple" slotting in of a new display/bit of kit.

We are in the middle of a complete glass cockpit upgrade and the thing that is giving me most grief is the new audio systems output impedance to the headset and the non standard helmet connector. A domino effect of lots of seemingly minor issues are being a real pain in the butt.

Anyway, back on thread, it can be difficult to determine if something is working intuitively as is, until someone makes a catastrophic mistake because they percieved the action they were undertaking under pressure was correct. Kegworth etc. The (un) intuitiveness of a certain control may never be fully highlighted as it doesn't have serious consequences if operated incorrectly and just becomes a pain that aircrew put up with.

The main point of the thread was to see if there were any thoughts from pilots as to why on earth certain items had been designed as they were. If they could also suggest improvements, not necessarily fully investigated/certifieable or even finacially viable, then I would be interested.

Any personal favorites from you?

[Jetstream Rider]

John - I'd be interested to know why you think the Russian standard is better?

I have experienced a sky pointer and a bank pointer, the sky pointer always points towards the sky, the bank pointer remains stationary on the aircraft as the bank marks on the AI move.

I have also seen the Russian version where the ground appears to be on the top, I see them as three different systems. Initially I hated the sky pointer, as I was used to a bank pointer. That was until I was told the sky pointer always pointed to the sky, so in a bad attitude you can always roll towards it. My level of training was such that changing didn't take too long and I'm quite happy to swap between the two now, but I shudder to think how long it would take to transition to the Russian standard.

I take novices in a mobile simulator in a trailer and in full motion sims. sometimes in the trailer sim people say "oh, the controls work backwards" as they see themselves driving a screen, rather than being in an "aircraft" and driving that. In other words they see themselves moving the graphics. This has never happened in the full motion sim, for obvious reasons. I like the fact the horizon outside and the AI look the same, the Russian stuff looks very weird to me although unfortunately I haven't had the chance to fly in a Russian aircraft.

In an odd attitude, what makes the Russian standard better?

[Jetstream Rider]

Nigd3 - it sounds really odd, but I'd like two cup holders and a good secure place to put my sunglasses. The first because in turbulence the cup of stuff often spills and then there is no where to put another drink without resorting to getting cloths etc which there may not be time for. The sunglasses thing is for rapid transition in and out of sunny conditions. If I take my glasses off and have no where to put them they often get in the way or distract me. This is especially true when descending into a cloud layer that may be turbulent or popping into a layer just before landing. I want to be able to take my glasses off, ditch them quickly and safely and have them ready for popping out of the layer later.

I realise I sound like such an airline pilot there, but the military chaps have visors they can slide up and down quickly. I rely on my leg, and the glasses often slip off causing me to fumble right when I don't want to.

I'll have a think about some more serious issues.

Just thought of one - I hate unnecessary abbreviations. They work well for things like VOR, ILS etc, but can be confusing. There is an Airbus message that says IF ABN XXX, a crew at my airline took it to mean AIRBORNE, when in fact it meant ABNORMAL and they did the wrong thing.

We have unnecessary abbreviations littered all around our cockpit when there is space to write the full word/s and the abbreviation isn't getting rid of something huge. Examples are GND for GROUND and L for LEFT. Sometimes reading the EICAS or checklist, the L and R would be much better written as LEFT or RIGHT.

[Nigd3]

JR
Sometimes its the seemingly simple ideas that can be prove to be worthwhile. Apart from keeping things convenient and allowing for time to concentrate on the more serious side of flying, you can maybe appreciate the slightly tongue in cheek scenario below:
AAIB report xyz - After dropping his sunglasses on the cockpit floor, the captain reached down to retrieve them when his left earlobe pressed the main hydraulics switch into the OFF position, that had been invertently left unguarded by the night shift maintenance crew. This caused numerous aural and visual alarms and as the captain raised his head quickly, he knocked a full beverage cup off the centre console with his nose. Fluid went down into the FMS CDU, short circuited the main power supply and caused a burning smell with some smoke.............

With regards abbreviations on aircraft, space and standardistation are the major limiting factors on EICAS etc. "LEFT" and "RIGHT" may be able to be written in full for certain captions, however not for other longer EICAS messages. With regards the "ABN" misinterpretation you quoted, "ABN" has been the standard abbreviation for well over 20 years for "abnormal", with "ABNRM" as an acceptable alternative. You will never get away from abbreviations and all I can suggest is greater familiaristaion with the systems/warning messages on the aircraft. Not much help on that one.

One of the major advantages in how the brain perceives the control-display connection with O-I compared to I-O ADIs is with an O-I (Russian) ADI, the movement of the control column to level the aircraft, is relative to the movement of the aircraft symbol being rotated. For example a left column movement in a right bank rotates the aircraft symbol left (CCW). In an I-O ADI (western), this same left column movement rotates the horizon in a right direction (CW). This is maybe highlighted by some of your students initially saying "oh, the controls work backwards", even though this may not be a prevalent in your full motion sim, it indicates a simple confusion in perception.

Thanks for the feedback.

[ianp]

Hi Nigd,
Have done a bit with glass cockpits but on helicopters. S'pose my main thought would don't be in such a hurry to lose the dials and knobs.

Dials can be much easier to interpret and assimilate at a glance. Engineers seem to love digitising stuff down to numbers and coloured strips.

Knobs, everyone likes to have multifunction soft keys to select crs pointers, baro setting, low height audios etc, sometimes life would be much easier with a good old knob rather than a few minutes stabbing away at bezel keys.
That iss it really without being too specific love those dials (or graphical equivalent) and knobs!

All the best

Ian

[Jetstream Rider]

Nigd3 - it doesn't matter how long ABN has been the abbreviation for "abnormal" the fact is a crew got it wrong on the day. 3 pointer altimeters used to be standard, they are not any more for good reason. I think a number of abbreviations should go the same way. If the EICAS screen isn't big enough to write the full caption, then make the screen bigger! It is much less of a problem nowadays where computer memory is not so very limited as it was. We have 511 mile limits on our range rings because of 512 KB limits on the data point, with modern aircraft this should no longer be an issue.

With Russian and Western AI's, I know what you mean, but what you see on the instrument and what you see outside are opposite. I can't see how that helps, although I am interested to hear other people's views as I am sure they will be interesting and make me re-evaluate my opinion. In my brain, the perception is that the Russian AI's are in the wrong sense - if my training had been different then maybe that wouldn't be true however.

IanP has made me think of something. I love the dial ASI on the 757, with manually moveable bugs and rolling numbers. The rolling numbers are great for seeing a trend, the needle also. Having bugs you can see all the time helps in giving a good gross error check. I used to fly an aircraft with a speed tape and I still find the dial and rolling numbers much better. The speed bugs on the tape used to disappear "up" the tape and only become visible as you went faster. Even though the bug and the number it was set to appeared when you set it, there was no visual cross check until you were barreling along the runway. I believe this was a factor in the Singapore Airlines tailscrape. With our ASI you can see just by looking whether the bugs are in a reasonable place and whether they are set for Flap 5, 15 or 20 takeoffs as the distance between the bottom bug and the next one gets bigger the larger the number of the flaps you use. Its helped me catch errors before.

Appearing numbers are next to useless (tell Honda!), rolling numbers are great. No trend in the first, plenty of trend in the second.

BTW my "students" (really the public) in the sim are looking at the outside screen, not the AI when they say it is "backwards".

[Double Zero]

Jetstream Rider,

It may interest you to know that besides his long-time input for Harrier & other cockpit displays, and of course his experience in the MIG 29, John Farley was going to ( I rather expect, did ) design the cockpit layout of Richard Noble's Farnborough Air Taxi project, which fell due to finance.

An ex-Flight Test chum had a job for a while helping design the Typhoon cockpit; it turned out much could be learned from computer games, which have to be simple & 3D for teenagers to fly spaceships !

[John Farley]

Jetstream Rider

You mention you have seen a Russian version where the ground appears to be on the top. That is a new one on me – but perhaps we are not talking about the same thing.

The Russian A/I display that I refer to has an aeroplane symbol that is free to roll with respect to the cockpit coaming and is viewed against a pitch drum that rotates about a horizontal axis fixed in the plane of the instrument panel. This makes for a very simple and reliable instrument which has no toppling limits like our A/Hs.

Back in 1990 I talked at length with the Mikoyan tps including their CTP Valery Menitsky and they were very open saying they had thoroughly evaluated both modes of display but still favoured theirs. Afterwards I attended the SETP symposium in LA in 1990 to help Valery give a paper there and afterwards there was an open discussion with the floor. During this I explained that before I did a MiG-29 evaluation that included a lot of manoeuvring in cloud (the base was 300ft) I had great reservations about unlearning my instinctive reactions and what model I should use in my head to ensure I did not get confused.

The model came from a nice soak in a bath the night before the flight where I reasoned that the view of this rolling aircraft against the pitch ladder was just like looking at my leader when I was flying line astern on him as he manoeuvred against the sky (something fighter pilots spend a lot of time doing) I reasoned that all I had to do was ‘remotely control my leader’ and make HIM do what I wanted MY aircraft to do. Bingo it worked like a charm and seemed very natural. Given that I was 57 at the time and had not flown a fast jet for several years the fact that I found it so natural must say a lot for the concept.

Of course (as an aside) this is how a lot of modern flight sim guys fly ‘their aircraft’ by viewing it from behind.

JF

[Double Zero]

That remark by John Farley about 'simulator guys' sounds very correct; at Tangmere museum, we have 3 'simulators' ( of course they're really just adapted games with decent throttle & stick controls, but with specially written software to involve Tangmere or people / aircraft which flew from there ).

The simulators give the facility to view the aircraft 'from the outside' at various angles - I have noticed people who are not trained pilots find this particularly useful, wheras going by the instruments would leave a big smoking hole in cyberspace...

Must be a lesson there somewhere about intuitive displays.

For those who fancy their chances, one can try to fly a Hunter through Tower Bridge, as was done in reality by a pilot who is a local.

I managed it at a relatively sedate pace, but when I tried to be a smartarse and go under the lower span ( it can be done ) my results were not pretty...

As soon as we are up & running again in March, I'll have another go.

BTW we have a large library available to the public, over 5,000 books.

I know, as I'm one of those cataloguing them !

[Jetstream Rider]

Double Zero - I have in fact met Mr Farley at a lecture he gave some 16 years ago. We had a chat afterwards and it remains one of the most informative and well explained lectures on aviation I have ever been to. I don't expect him to remember a little boy at North Weald asking him about Ski jumps for the Harrier, but I remember it well!

The reason I ask here is because I know that with people like John and the others on this forum, I will get a decent well explained response that will make me think, rather than uninformed speculation.

John - Thanks for explaining that, I've not seen the instrument which you describe. The one I saw was decidedly odd. I thought it had toppled, but apparently not. I'll see if I can find one to look at.

Kind regards.

[Shawn Coyle]

Having tried both sky and ground pointer AI's in numerous aircraft and sims, my observation is that the sky pointer had more initial wrong moves to change bank angle than the ground pointer.
Other areas where controls / displays could be set up two different ways were in helicopter landing light switches and gimbal imaging system (FLIR, etc).
For the helicopter landing lights the options are moving the switch forward moves the light up or it moves it down. After lots of discussions, the test was to see which orientation led to the most initial incorrect movements - and the orientation with the 'move the switch up to move the light up' won hands down. Ditto for the FLIR- did lots of demos of FLIR to first time users, and engineers loved the move the switch up to move the line of sight up. Pilots hated it.
In both cases if the control had been a joystick type of control instead of a fore-aft switch, it might have been more obvious to the designers to make the control work more like an aircraft flight control.
Of course, in the US Army's OH-58D with it's mast mounted sight, the problem of which way should the sight be controlled was solved by putting in a switch to allow the operator to choose...

[Double Zero]

I'm not a pilot, but have done a lot of flying as a 'free autopilot' in light aircraft when the CPL or ferrying Test Pilot was bored or giving me the chance, + a lot of 'simulator' time in varying degrees of realism, everything from multi-million £ jobs to PC games; my instinct with the light / FLIR would certainly be push forward, go down...

Incidentally, while not re. displays, this is a similar snag; I knew a very experienced Harrier Test Pilot ( not J.F. ) who for some reason had to test microlights of the 'hang glider with a pusher engine' variety; he remarked it went against the grain to push the wing control bar forward to go up !

[John Farley]

JR

I wonder if the instrument you saw was switched off and so the pitch drum gyro was not running - that could have explained things

JF

[Double Zero]

One thing which horrified me, when I spent a season in ( clapped out ) Cessna 172's; one day we were trundling, straight and level, when the artificial horizon keeled over.

The senior ( and aerobatic trained ) CPL remarked as if it was nothing, " I see the vacuum's failed " but it struck me as damn dangerous, especially for inexperienced pilots caught out in IFR; am I right in thinking that in something like say, a Hawk, an 'inop' red signal would have come up over the instrument ?

I do know several Sea Harrier pilots were said to have been killed on attempting vertical landing ( source- another Sea Harrier Test Pilot, not J.F. ) when following their artificial horizon at night & the gyro's toppled, leading into a steep bank & crash into the sea.

Mind you, that pilot liked the Harrier, but wouldn't step into any aircraft, light G.A. or Military, unless a lot of £ signs flashed before him.

[Jetstream Rider]

JF - possibly, that did cross my mind, but apparently not according to the person I was with at the time. Will dig around and see if I can find a link to a picture.


Its interesting to note above that flight sim pilots on their computer normally fly the sim seeing their aircraft from behind. Back in my youth I did that with MS flight sim, as I hated not being able to see sideways or have any peripheral vision.

In my experience there is a big difference between sitting in a fixed base sim and a full motion sim. Even if the motion is off in a full motion sim, ones brain is still fooled into thinking it is moving - in fact I was "flying" one with the motion off and the back door open. Looking behind me as the sim did some visual gyroscopics was quite disorientating. However most fixed based sims have poorer visuals, usually just a flat front screen. If this is the case it leads people to fly the screen, not the aeroplane, at least if they have no experience. This does not seem to happen in a full motion, or perhaps I should say full screen sim.

[Jetstream Rider]

Here are a couple of pictures of a Yak 18T cockpit's with a "brown on top" AI, that I mention above.

Photos: Yakovlev Yak-18T Aircraft Pictures | Airliners.net (http://www.airliners.net/photo/Yakovlev-Yak-18T/1454088/L/&width=1200&height=842&sok=&sort=&photo_nr=&prev_id=&next_id=)

Photos: Yakovlev Yak-18T Aircraft Pictures | Airliners.net (http://www.airliners.net/photo/Yakovlev-Yak-18T/1250999/L/&width=1200&height=837&sok=&sort=&photo_nr=&prev_id=&next_id=)

If the links don't work they are Airliners.net pictures 1454088 and 1250999

I've never flown with one of these, but especially the one that is blue on the bottom, to me seems completely wrong. In IMC in an unusual attitude I'm sure I'd get it wrong. With different basic training however perhaps not.

I'm glad I found the pics as I thought I was dreaming! Definitely not toppled here as in flight.

I had a look at some Mig 29 cockpit shots too and it appears to be very different to the above, which I now know isn't what I initially thought it to be.

[Rich Lee]

When you take off to the west from LAX on a smog alert day the brown smog above the horizon, ocean blue below AI would be very appropriate.

I am a bit puzzled by all this. Is anyone aware of an accident directly attributed to the colour scheme, or IO/OI design of an AI?

So far this discussion seems a bit like arguing which is the better design - black shoes or brown shoes?

[Jetstream Rider]

Just to be clear here, I don't want an argument. I'm interested in hearing other (most respected) people's views about something that at the moment I find quite odd.

Having said that I don't want to hijack the thread, but I find the human factor thing really interesting and hearing from others makes it more so. The pics posted above are to clear up any misunderstanding of what I mentioned above, which is quite clearly not what John Farley meant in the first place.

[Double Zero]

The chap mentioning 'brown or black shoes' clearly hasn't been in a situation where clear, intuative displays might save the collective arses of himself & any passengers.

Personally I'd like 'standby' traditional instruments a bit more prominent - it's unwise to rely on glass cockpits in case of emergency, but companies don't want to admit this - applies to everything from airliners to fighters.

[Jetstream Rider]

I'd like standby instruments to be better quality too and in a standard layout.

[Nigd3]

Maybe someone who has flown a "Highways in the sky" type of EVS can give an opinion on how intuitive they are to fly.
I believe it uses a similar principle to the Russian O-I ADI, in that the horizon is fixed and the aircraft symbol moves in relation to it?

Double Zero, you might just want to retract what you said previously about RL :)
Our latest cockpit doesnt have any traditional (electro-mechanical) standby instruments. The SFD is backed up by an independent battery, for a main battery and generator failure, that also powers independent sensors for air data and attitude, as obviously required by regulations. In the case of a "simple" PFD failure, the NAV is also connected to it, hence the SFD can display QDM, QDR, GS, LOC and DME. Give me that over an E2B and mechanical ADI and Alt any day.

JR - please don't feel you are hijacking the thread. The HF side of cockpit designs are exactly what I would like information on.

[Nigd3]

JR

With regards your links to Yak-18T photos, the first link looks to be an Aussie registered aircraft....that explains that, the AI is confused when it went down to the southern hemisphere and hence upside down :)............. that is very weird with the blue representing the ground.

The second photo link is showing a very old grey-sky/black for ground, which is not so confusing as the first AI.

I can't tell if they are O-I or I-O with the attitudes shown. Maybe someone with better eyesight can clarify.

RL - I don't know if any accidents have been directly attributed to confusion caused by the type of AI installed in the aircraft. I would imagine the greatest problem with determining that is asking the best person afterwards. I do know that significant sim type testing using instantly displayed UA's and then measuring response time to correct, degree of control movement and also correct control movement to recover the aircraft, came down quite heavily in favour of the Russioan O-I ADI. The O-I gave a faster response for recovery and also fewer erroneous corrections.

[hugel]

It is rarely possible to star with a blank sheet of paper designing a cockpit layout. There are historical positionings and conventions, cultural preferences (left to right, top to bottom you say ?) .

There is an interesting Airbus Flight Ops Briefing Note: Human Factors Aspects in Incidents/Accidents (http://www.skybrary.aero/bookshelf/books/175.pdf) in which the Operations Golden rules which address possible causal effects under the heading of "Use of Automation" cite:

Lack of situational awareness
Interaction with Automation
Overreliance on automation
Lack of Crew Cross CheckIt also supplies a number of examples of possible hazards which can result from such interaction. My point in mentioning this is that in an integrated instrument suite, almost any aspect of the HMI can cause such problems if the pilot is abstracted from full control.

For example, if a certain status information is missing from a display format then it may be assumed by the pilot that it is invalid (as one generally hides non valid display data) but it may simply have been moved in a software update to a different panel layout in this new cockpit...

re. comments on physical reversionary instrument more reliable: glass cockpits are great for presenting fused sensor inputs, and integrated displays. The theory is that NTD displays can be routed to any identical glass panel in the cockpit in the event of a hardware failure so should providing redundancy of display device as well as source.

hugel

[hugel]

Another thing worth mentioning is that type commonality to reduce type training within a family is a major factor in new cockpit design. Propogating initial flight deck layouts formats and features across an aircraft family is encouraged and redefining a switch caption or position may have huge ramifications.

hugel

[Double Zero]

NIGD3,

Thanks, but I won't be retracting anything much soon.

My source was various Test Pilots - I, though not a pilot, was alongside them, sometimes literally.

I would hope, and understand it is the case ( ? ) that main standby instruments are pretty much in a standard configuration whether Boeing, Airbus, whatever - & the same is begiining to apply to military aircraft ?

I can't help thinking that along with a RAT for control surface hydraulics, one can barely imagine a much better place for a solar panel to handle electrics / keep a standby battery topped up than the upper surface of an airliner.

Of course this would require a cleaning system, therefore money; I remember being at a Scottish test range when the c/o organised an air to air photo-shoot from an Andover ( thankfully I was not involved ) and all the shots showed the upper surfaces of the Buccaneer covered in Guano !

It's quite a big aircraft, wings way above head level ( have a look at the undercarriage up close ) but it didn't say much for inspection procedures.

[FlightTester]

Sorry to start thread drift, but can you please explain what appears to be a somewaht Luddite view based on the comment below


Personally I'd like 'standby' traditional instruments a bit more prominent - it's unwise to rely on glass cockpits in case of emergency, but companies don't want to admit this - applies to everything from airliners to fighters.


In all the Pt 25 aircraft I fly there are zero "traditional" standby instruments, they're all glass cockpits including the EISI (Electronic Integrated Standby Instrument). The EISI meets in all ways FAR's 1301 and 1309 and as far as I'm aware there has never been a case whereby both ADC's (also electronic) have failed at the same time as all four flight displays and the EISI and left the crew in the dark with no flight information.

Getting back onto the thread and the HMI - if one did think about having the AI IO or OI blue over brown or brown over blue, then you would have to convince the manufacturers of the stand alone EISI or it's equivalent to conform too.

[Jetstream Rider]

See here:

Air Accidents Investigation Branch: S2/2005 Airbus A319-131, G-EUOB (http://www.aaib.gov.uk/publications/special_bulletins/s2_2005_airbus_a319_131__g_euob.cfm)

5 mins avail on the standby AI unless they had sorted it.

I don't speak Airbus, so some of this is lost on me, but its pretty serious all the same.

[Milt]

What about our main flight controls?

I have even come across some engine throttle controls where one has to pull a knob towards you to increase power. Another throttle control was positioned under the seat!! No instinct to be found there.

Which way is instinctive for the twist grip engine control in most helicopters?

Then incredulously all of our rudder controls are the wrong way round.

I posted the following some years ago.

Rudders in Reverse

Strange that all aircraft pilots have been retrained away from natural instincts and childhood learning for rudder yaw/directional control.
Most don't even realise that this happened during the first few hours of their training and have rarely been prompted to consider how extraordinary is the result..

Human steering on the ground may have started on horseback as the evolutionary beginning of the human steering process.
Then the learning progression through the tricycle, billycart, bicycle, motorcycle and motor vehicles.

Then go fly and the instructor introduces you to a rudder bar or the equivalent and surprise, surprise it works the opposite way round. Oops.

Generally takes 2/3 hours of diversionary concentration before the reversal starts to become sub-conscious - remember?

Test pilots and purists often speculate on the ability of the experienced pilot to operate nosewheel steering and rudder simultaneously on a landing roll-out without any apparent mental conflict. Perhaps if a nose wheel steering wheel was changed to a miniature rudder bar there would be considerable mental conflict or perhaps we have nerves with selective reversing crossovers.

Oddly I don't recall any difficulty with the tiller in the Beverley which one could imagine to be the spoke of a wheel.

I well remember being caught out in a Folland Gnat having a prototype full slab tail. With gear down at slow speed and normal full nose up trim, full back stick was inadequate to prevent nose down pitch. One was then forced to go for over-ride trim via a two way switch on the instrument panel. Instinctively I selected the switch down as though to instinctively rotate the nose up - Whoops. It had been installed the other way. A green field rapidly enlarging gets your attention. Happily a quick switch reversal sorted things out otherwise I would have had some interesting practice with inverted flying.

[FlightTester]

Interesting reading and it has my curiosity peaked. This is one of those situations that should be in the "10 to the minus 9 chance of probability" category so beloved of some of my FMEA colleagues. The five minutes of power remaining for the standby is quite normal in the case of a total electrical failure (FAR 25.1351), but (and this is the main question here) why didn't the RAT or whatever the Airbus equivalent is deploy to restore power? This seems to be a very strange combination of the aircraft apparently losing all power (only reason I can think of for all the displays to go dark) and yet not reverting to standby power automatically. Very strange.

I shall eagerly await the final report!:hmm:

[Jetstream Rider]

There is a second report a while later. Unfortunately the conclusion is pretty much "we don't know", its still worth a read though.

Air Accidents Investigation Branch: S3/2006 Airbus A319-131, G-EUOB (http://www.aaib.gov.uk/publications/special_bulletins/s3_2006_airbus_a319_131__g_euob.cfm)

There appear to be a fair few things that "can't happen" having happened in aircraft accidents, which is why I never believe anyone who says "oh don't worry, that can't happen" ;)

Milt - I've never found the rudder to be backwards. If you see it as a "bar" like handlebars on a bike I can understand why it is thought to be backwards, but why would one want to roll right and use left rudder in a normally balanced turn? That seems very odd to me. It seems entirely natural to push right, go right. I would find it very odd to push right, go left. I do know others who think it is backwards and have the same opinion to you, so there is obviously no universal correct way round. Every time I have thought about it though, having it in a different sense seems mightily odd. Steering down the runway would be even more like chasing a fox!

There is a light aircraft around with reversed aileron controls. It has a control wheel and is from the 30's I believe - can't think of its name. I have a feeling the Shuttleworth collection had some input to its restoration, but otherwise my memory of it is hazy.

[Double Zero]

Shirley,

This is why ground checks waggling the control surfaces with someone the pilot can trust as an external observer to give a 'thumbs up' is worth their weight in gold.

Might cost airlines a precious couple of minutes - tough !

[FlightTester]

I find it quite natural on the rudder to push left go left, but there again I also ride a motorcycle.


Then the learning progression through the tricycle, billycart, bicycle, motorcycle and motor vehicles.



I know it sounds counterintuitive but on a motorcycle at any speed above a walking pace in order to go left you push left on the bars. This draws a nice parallel to the rudder pedals/bar, I think of it as an increase in the pressure of my hand or foot in the direction I want to go.

[Milt]

Flight Tester.

Consider your motorcycle turns a little deeper.
Initially you have to START a turn with a force on the handlebars into the turn which initiates a bank/roll of the machine. The bank immediately and progressively causes turning instability as a result of its deliberate design and if left to itself would automatically tighten to a spin out. Once into a turn you have to use an opposite handlebar force to counter the instability. Motorcycle riders seem to prefer this type feel.

I wouldn't care to approve such instability for an aircraft!!

[FlightTester]

Milt,


Consider your motorcycle turns a little deeper.
Initially you have to START a turn with a force on the handlebars into the turn which initiates a bank/roll of the machine. The bank immediately and progressively causes turning instability as a result of its deliberate design and if left to itself would automatically tighten to a spin out. Once into a turn you have to use an opposite handlebar force to counter the instability. Motorcycle riders seem to prefer this type feel.


You must ride some strange motorcycles or ride them strangely. I know I certainly don't prefer any feel of instability and I've been riding for near on thirty years.

[Rich Lee]

Nigd3I do know that significant sim type testing using instantly displayed UA's and then measuring response time to correct, degree of control movement and also correct control movement to recover the aircraft, came down quite heavily in favour of the Russioan O-I ADI. The O-I gave a faster response for recovery and also fewer erroneous corrections.
I find your comments related to testing that has demonstrated a pilot preference for the Russian O-I ADI very interesting. Is there a published report you might be able to direct me towards; perhaps something online at Royal Aeronautical Society and/or Society of Experimental Test Pilot?

[Nigd3]

RL

A good source to start is "The Outside-In Attitude Display Revisited" by Fred H Previc and William R Ercoline. This was published by the International Journal of Aviation Psychology, online in 1999.

Another interesting read is "Methods for Validating Cockpit Design" by Gideon Singer, which details testing of roll reversal errors when using different roll index formats.

[Shawn Coyle]

The current attitude indicator sky pointer was mandated by the SAE Large Aircraft Cockpit Working group. Most people don't even know they exist.

[hugel]

Airbus have their own Cockpit Evaluation Group and Cockpit Integration Group, and develop equipment requirements. By the time most designers down the supply chain (at equipment manufacturers for example) get to see the requirements, many of the decisions (colours/layout/symbology) are already made.
Remember the glass cockpit displays have multiple layers and overlays possible so ensuring consistency is not that easy when multiple suppliers are developing the equipments.

hugel

[Double Zero]

I didn't think it was legal, let alone sensible to have totally electronic instruments in any cockpit, especially airliners ?

I know Russian fighters tend to rely on the HUD, ( I've photographed M-29's & SU-27's cockpits, which didn't go down very well at the time ) but they still have standby instruments and very good ejection seats !

[Rich Lee]

Nigd3 Thank you. I found both the documents you recommended.

Shawn Your post confirms my understanding for transport aircraft. I am also aware of how Sperry, Bendix and Collins drove early instrument design.

I have not been aware of studies indicating a clear preference for O-I v I-O displays. My personal preference based on testing of both US and Russian equipment would be contrary, though I find both designs functional. I would like to understand the test conditions of studies related to an O-I v I-O preference. I am involved in a new design/test effort for a high workload cockpit. We are attempting to think outside of the box and if a significant improvement in situational awareness and/or reduced workload can be substantiated, or even if a clear preference has been demonstrated in testing, I would like to include O-I in planned testing using both test and operational pilots.

[Jetstream Rider]

I've seen a new aircraft with all EFIS instruments including the standby's - I have no idea how they were driven, but certainly all the instruments were all flat screen.

Interestingly I heard of an accident with a Diamond TwinStar (I'm pretty sure that's what it was - new light twin though.) It has FADEC to control the engines - the alternators on the engines are not quite powerful enough to run everything when the gear retracts (electrically), so it robs power from the battery for a bit while the gear comes up. The problem was the battery had gone flat in the accident aircraft and had not been charged in accordance with the POH. The upshot was that on gear retract, there was no power to rob from the battery, and not enough oomph to drive the other bits and bobs, including the FADEC, hence the double engine failure that ensued.

Some of these all singing all dancing systems sometimes leave me a bit concerned, things like the Airbus incidents linked above do show that sometimes we are not quite as forward thinking as we would like to be. (Without wanting to sound like a luddite, I love technology, but only when it helps).

[Rich Lee]

Jetstream I mostly agree with you, but mostly because I am a throwback to a by-gone era. The real problem is that nobody designs single task flight instruments anymore. We can argue the superiority of Inside-Out, Outside-In, Grapefruit (Arc-Segmented), Highway In The Sky, Integrated Flight Path Vector and other displays but must do so within the context of the entire information system. If we consider a transport aircraft there is one solution, for a fighter aircraft there is another solution, for helicopters there are so many tasks that one elegant solution is a design dream never to be realized. Then there is the mission. If the mission is to fly IMC along established airways to a high category landing I might prefer one design over another. If the mission is a high speed, low level ingress in zero/zero to attack a target I will never see visually, then I will certainly want another design.

It is impossible to design one perfect system for all applications, but it is possible to merge the best of different designs when there is task similarity.

A real problem for me is that data from simulator studies are often very different from aircraft studies. The cost of a test in an aircraft is much higher than a simulator study so more and more of this type of testing is being conducted in simulators; yet because of limited visual and other cues, I might prefer one display in a simulator and strongly prefer another for an aircraft. I think of video games. I almost always prefer and choose an Outside-In display because these provide the most cueing for the gaming task. I feel the same about simulators, because even the best of full motion simulators are cue deprived environments. In the aircraft I have a preference for Inside-Out displays. The question I am asking myself now is do I have this preference only because I am used to that type of display, or are there other more compelling reasons for the preference?

We are increasingly aware of an age biased flight display preference. The XBox generation see things much differently than the pre-computer generations. Although both can learn to adapt to each others systems, when asked they seem to demonstrate a primacy preference.

[Nigd3]

One of the best pieces of advice I heard regarding designing instruments is "Data is not information, unless it can be interpreted". If a pilot has to stop and think "what the hell does that mean", as stated previously regarding the caption ABN, then it is not an intuitive design. This obviously has the caviat "with reasonable training".

It sometimes can be difficult not to be distracted and objectively assess something in terms of does it do the job, even when presented with multiple/a significant failure, rather than, it looks flash and works wonderfully when all is operating ok, in normal flight profiles.

RL - maybe you should update the much used/abused phrase of "thinking outside the box" to "thinking outside the xbox". :):D:) .......I'll get my coat.
With regards your preference for the I-O ADI when actually flying, the publications I recomended may go some way to explaining this. When you lose certain sensory cues, that you have been extensively conditioned/trained to interpret, that are not represented in a sim or on a PC game, the brains natural preference regards the O-I as the more intuitive presentation. This is my view anyway.

[FlightTester]

When you lose certain sensory cues, that you have been extensively conditioned/trained to interpret,.


As part of one of our Human Factors Workshops we were shown a video of an F-16 pilot in combat being locked up and fired upon by multiple SAM sites (he escaped). The interesting thing about the whole sequence (which lasted for around two minutes) was that all he had to do to escape the Missile Engagement Zone was take up a southerly heading - that was it, no requirement to pop chaff and flares, no altitude changes, no power changes - just fly South for thirty seconds. His wingman was yelling at him over the radio to follow him and fly south.

The pilot of the F-16 had reached a point of sensory overload, adrenalin was flowing, breathing rate had gone up and gotten shallower and he was scared - result, the higher brain functions had shut down and the guy was flying a fast jet using what the neuroscientists call "the caveman path". Didn't matter what he'd been conditioned/trained to interpret - as a species we have had millions of years to evolve but we are still hard wired to avoid being eaten by large animals on the African savannah - instinctively we know that the best way to avoid the large 300 pound tawny cat bearing down on us is to jink because we know it can outrun us in a straight line. As a result of his hard wired response, the pilot elected to jink his aircraft left and right but remain in the MEZ with missiles leaving contrails all around the aircraft. He eventually got a grip of his caveman instincts and flew south out of the MEZ.

It was a salutory reminder that even highly trained and conditioned people can reach overload under stress and that cockpits need to be designed bearing those situations in mind.

[Rich Lee]

Nigd3[RL - maybe you should update the much used/abused phrase of "thinking outside the box" to "thinking outside the xbox". /QUOTE]Clever. There's a giggle in that thought.

[QUOTE]With regards your preference for the I-O ADI when actually flying, the publications I recomended may go some way to explaining this. When you lose certain sensory cues, that you have been extensively conditioned/trained to interpret, that are not represented in a sim or on a PC game, the brains natural preference regards the O-I as the more intuitive presentation.

First, I accept that I am extensively conditioned but I like to believe that my training and experience allows me to overcome this conditioning in the conduct of research and test. I have noted that there are several researchers and pilots who seem to share your preference for the O-I dispaly; yet my reading to date, admittedly limited to your recommend publications and about 10 other papers, seems to provide no real concensus for a clear Outside-In preference. It is early in my research so I have yet to reach any personal conclusions, but I am beginning to feel as if a simple comparison of design concepts will not be possible as there are too many variables in the published research to form a useful compartive matrix. I am, however, seeing a preference in some of the more recent documents for the Arc-Segmented Attitude Reference Display, which I am sure you are aware is classified as an Inside-Out concept. My real difficulty in comparing the various displays is that the published researched I have read to date are not conducted using a single standardized research protocal. Further, the tests never seem to evaluate more than one display and many use old technology or adapted computer displays. For instance, one uses a panel mounted display, another legacy instrument panel displays, another a computer screen, another HMD fixed or non-fixed, another full face visor (fixed and moving frame of reference), and still another point-in-space/infinity projection - yet most researchers use only one display for their tests and this introduces an obvious test bias. One might conclude using a panel mounted flat screen display that O-I is preferred while another using a helmet mounted HMD with superimposed and fused FLIR/IR imaging underlay and flight and navigation symbology overlay that an I-O is the preferred display protocal - which then becomes the design standard when both displays are available for the pilot to use? Sometimes the design choices are not so clear. Most aircraft companies understand that testing an infinite matrix is a bit cost prohibitive and that is why introduction of any new standard requires clear and convincing proof that the new standard as far superior to the old.

[Nigd3]

RL - Firstly apologies. I have no real knowledge of your flight training or test and evaluation experience, hence making assumptions on your capability to adapt to different situations is unfair. In my defence, it was intended as a generalistic viewpoint, rather than trying to identify an individauls (your) behaviour, although it doesn't really read that way.

It would be very interesting to hear if you do assess an O-I ADI, or any other formats and any results that you are allowed to publicly detail.

Another problem that is stated in one of the publications I listed, is that most research on O-I ADIs was undertaken in the 1970's and not a lot has happened since.

[Jetstream Rider]

Rich - I agree with you too, I cannot imagine how a fast jet pilot would be able to accomplish a mission with the sort of instrumentation I look at every day. There is a real difficulty in specialising instruments for a given job though, and that is when someone transfers from one to the other.

I've never flown an Airbus, but have discussed at length some of the the differences with various colleagues who have. Plenty of stuff makes me think "why on earth did they do that?" and after a few conversations and different views I begin to understand what the designers were getting at (at least some of it, some of the ideas still seem totally bonkers to me!). I am sure it would be the same the other way round. The fact is that people change from Airbus to Boeing and from fast jet to airliner, so some common ground does help.

We also then get stuck in ruts - if we standardise everything, then when the new technology comes along it is suddenly non standard, so do we stay in the "dark ages" all the time, or improve? It is such a difficult situation, that often I think we need to be thankful that humans are so adaptable. No cockpit design is ever going to get it right, but that is no excuse for making a bad one!

There is so much that seems obvious and intuitive to me - but a lot of that is due to my upbringing and training. Red is lucky in China, so probably not the best colour to use for a warning caption. GEAR NOT DOWN - lucky us!

[Rich Lee]

Nigd3 There was no offense taken in anything you have written and no need for an apology. There is merit in your opinion and in this discussion.

I am, as others in this and other forums have at times noted, a rather thick-skinned and witted American who only rarely understands he has been insulted - even when such insult is intentional. The truth of it is, if I didn't listen to those who disagree with me I would never learn anything. You will also note that when someone says something monumentally stupid in any forum other than Jetblast, I usually don't bother to answer. I have discovered in those cases a reply is a bit like wrestling with a pig in the mud; sooner or later you realize the pig likes it.

You raised a very interesting point and given the comments of test pilots I have come to respect in this forum that have agreed with your opinion, you have caused me to evaluate my own bias with, as Jetstream Rider so eloquently stated in the last post, a hope of finding the more elegant solution rather than just doing the same thing because that is the way we have always done things in the past. Your comments have already been very beneficial as I have questioned my core beliefs and as a result of the research have a better understanding of the evolution of the various designs. As some bard once said, there are many paths to the top of a mountain.

[Jetstream Rider]

I've just got out of the bath and I've been thinking. In a sim session one day we were discussing at the briefing what we would do if we have an engine failure on a North Atlantic Track - we both came up with reasonable ideas and then jumped in the box. When we were actually presented with the scenario some time later, we did something different. Both ways were acceptable, within SOP's, but nevertheless different. My psychology isn't up to much, but I reckon we were probably using different bits of our brains.

I see the same thing with the endless questionairres we are sent by various people and businesses - what you actually write may be very different from your view. Questions such as "Are you proud to work for xxx?" are easy to identify (yes and no, so where do I tick?), but others less so. When you introduce lack of cues, it compounds the problem, when carrying out the survey, you are usually deprived of the cues you need like a dirty table top in a restaurant. I wonder how much of a factor this is in aviation research? Would the outcomes of some of these O/I v's I/O studies for instance actually be a long way in error?

That might sound like I like one type and am sticking to it and only finding things to support my view - but I promise that's not the case! I mean in general terms, rather than specifically. After all there are instruments out there that have been through many meetings and tests, yet still produce erroneous results.

Was thinking of a HUD too - airliners are getting them soon - does what works best for a HUD, work differently for a panel? Having not flown with a HUD, I have no idea. Do we have multicoloured ones now? How do green lines compare with glorious technicolor?

[FlightTester]

Was thinking of a HUD too - airliners are getting them soon - does what works best for a HUD, work differently for a panel? Having not flown with a HUD, I have no idea.


Just finished development flying for certifying HUD on one of our large business jets. Short answer is yes. There are things that you want on the panel that you don't want on the HUD and vice versa - nice feature on the HUD is the flare cue - bit like a FD pitch target. Wouldn't want it on the panel display though. No colour but green on the HUD, so you have to be more inventive with the failure indications - either strikethroughs or boxes - sometimes not as intuitive as a yellow or green indication. Likewise, with the Flight Mode Annunciators.

In terms of distraction the HUD can be a major headache - on the HDD having the flight path acceleration cue bouncing up and down during taxi is not a major distraction, when it's collimated on infinity and doing it right in front of your face in symbology that's "apparently" 6 feet high it a real bugger!

[ICT_SLB]

We've had HUDs on airliners for well over twenty years that have got progressively more & more sophisticated but still with only one color - green. That's because the reflection HUD uses a single frequency holographic mirror.

Given the main theme in this thread,the HUD is possibly the one modern display that doesn't do Unusual Attiudes (UA) very well. You can have sky pointers, declutter at set Pitch & Roll angles and include ladders and lines but it's still not easy to decide which way is up - especially when you're in a total whiteout with no outside clues.

The other problem when you're only allowed a single color is that it's relatively easy to draw something that actually will "pop" on you such that the shape goes inside out as you blink.....

[Jet_A_Knight]

Rich Lee asked: I am a bit puzzled by all this. Is anyone aware of an accident directly attributed to the colour scheme, or IO/OI design of an AI?

"On 10 January 2000, at 16:54:10 UTC, in darkness, on runway 28 of Zurich airport, the Saab 340B aircraft of the Crossair airline company, registered HB-AKK, began its scheduled flight CRX 498 to Dresden. Two minutes and 17 seconds later, after a right-hand spiral dive, the aircraft crashed on an open field near Au, Nassenwil ZH."

The commander was a Moldovan citizen who had flown nearly all his career in Soviet aircraft.

"The following factors may have contributed to the accident:

• The commander remained unilaterally firm in perceptions which suggested a left turn direction to him.

• When interpreting the attitude display instruments under stress, the commander resorted toa reaction pattern (heuristics) which he had learned earlier.

• The commander’s capacity for analysis and critical assessment of the situation were possibly limited as a result of the effects of medication."

http://www.bfu.admin.ch/common/pdf/1781_e.pdf

[Shawn Coyle]

John Maris of Marinvent has patented Dynamic Non-Linear Display formats that provide information about the complete altitude and airspeed range of the aircraft (as just two examples) on tape instruments. Ideal for unusual attitudes and dynamic maneuvers like emergency descents. Anyone want to try them in an R&D setting can send me a PM.

[steve_oc]

The Flash Airlines B737 accident at Sharm el Sheikh on 3 Jan 2004 was partially attributed to spatial disorientation of the Commander and one of the factors was allegedly his Air Force background (Mig 21). Note that the Egyptian CAA report and the NTSB and BEA comments do not fully agree. See:
BEA (http://www.bea.aero/anglaise/bea/bea.htm)
and go to Reports/Search 2004.

[BentStick]

The story regarding the wing sweep lever for the F-111, in that it was originally designed with the function of lever forward-wings sweep forward, lever back-wings sweep back, perfect one to one mapping, engineers logical solution. However pilots perception is lever forward=go faster, lever back=go slower, along with the other controls in the cockpit that meant something went faster if you pushed it forward and vice versa. So as the pilot wanted to slow down for landing, the wing sweep lever was moved aft and the wings swept back, which was obviously not very nice. The wing sweep lever was subsequently re-designed to stop any potential confusion for the pilots.



Nigd3 - The F-111 wing sweep lever was not such a brain stretch and was never redesigned. It remains as ever, wing sweep lever aft = wings aft. The relationship between the F-111 park brake handle and the hook handle, now that's another story.

[Nigd3]

Bentstick

Interesting update/correction on the wing sweep lever. It is contradictory to the HMI thesis I read but it sounds like you have first hand knowledge of the lever and its operation, so I'm not really in a position to dispute with any real strength.

Whats the story with the park brake and hook handles?

[BentStick]

You can confirm it for yourself by looking at cockpit photos of F111s (any model, any era) when parked on the ramp. You'll notice that the wing sweep lever is always fully forward (16 deg).

The Hook and park Brake handles were of similar(ish) shape and size and mounted about 10cm apart, just fwd of the wing sweep lever(Park break was grey, hook handle was yellow) . Many a Pig driver blew the hook down while attempting to engage the park brake.

[Ajay Aeri]

But did u ask them if they were happy flying the Airbus??

[bauduin_alex]

hello
I think it is a wrong approach to want to change instruments. We've saddly lost the first SF34 in ZRH because of this you're trying to tell me?
I think that you're trying to solve the "how" this happened while you should try to fix the "why".
But for heck of it ...I hate this in cockpits:
A) Clicking. Easy,787, 380, 777, E145,E170...Never heard about touch screens like in jet fighters? Why do I need to see Windows like menu in an aircraft.
B) FAULT lights with partial system working. Is this thing working or not????
C) Poor audio radio quality. Should be digital (less fatigue) with auto frequency switching
D) Control laws: Too complicated and there are always exceptions. Why? The engineer will give you 10x10000 reasons why, but he's not flying the thing.
E) Virtual MCDU keyboards. :{
F) Limitations. Do not operate the gear if pressure is below 1450 PSI. Do I care? No, I need to raise of lower the drag generator. End of story. Fadec can compute several parameters per second but I still need to keep an eye on the oil pressure when starting the engines. Thanks automation.
G) Switches versus push buttons. I prefer flush, pushed in for normal, LED bulbs. Green= Works ON. Red = failed stopped operation. Not lit = OFF.
H) Flap handle. Should be kept for backup only and a new logic incorporated in speed modes allowing flaps extension for slowing down. EGPWS will yell at you TOO LOOW GEAR/FLAPS but no piece of automation here...still manually have to lower the gear. Even 3 radio altimeters not sufficent to tell that we can safely raise the gear automatically. We have auto slats but no auto flaps.
I) Garmin 1000 on VFR (mainly) machines. So you have to operate VFR while spending most of your time punching buttons head down on the displays of a single pilot operated machine? Watch the other guy.
J) 0/0 capabilities. Engineering dream. How do I taxi if I cannot legally rely on the moving map of my EFB?
K) Airbus controls (stick and throttles) not showing movements.
L) Pure engineering concepts. 'Kmon have you ever seen a concept car commercially available? No, that's why it is called a concept. Concept and practical don't go along (use is practical but manufacturing is nightmare).
If you're french and born in Blagnac then you can understand Crew Operating Manual. (How to operate the crew right?). If you're from KBFI then you can understand Aircraft Operating Manual (How to operate the ship).
M) Vertical speed mode. This thing is on since 800 BC on ships and no one came up with something smooth.
N) HF radio. Yeah, I still have my 56k modem for surfing the web!

I love:
A) EVS, HUD
B) EICAS/ECAM message auto arrange
C) OEI auto pop up for SID, Climb...
D) TAC on 777
E) Antiskid (everybody thinks it is granted like on cars. Remember 40 years ago...)
F) Wx radar mapping by FL.
G) FANS, ADS, Satcom...
H) Electronic checklist
I) EFBs vs laptops.

To conclude:
The why vs the how...
It is very complicated for a pilot to write down a robust spec to an engineer.
It is very easy for the engineer to implement the IF ...CONDITION then ACTION from the spec, but it is awfully complicated to write a ELSE if nothing is given in the spec. Most of the problems are coming for this missing statement (unspecified). And it is getting worse because of commercial pressure( shorter coding, testing, integration, robustness test time), more and more combination of conditions are remaining untested or deliberately put into the class "unlikely to occur".
"This failed because these conditions where never tested". "This plane crashed because pilot was tired". You would like to design something that will tell a tired pilot he's making a mistake but next thing management will ask is to have our flight duty extended and fly with more fatigue.
I do beleive that making these 2 worlds (Engineers/Pilots) "talking" together is an art. I love to write sequencers in C versus "Cool" realtime applications in Java with embedded windows XP. But between you and me: KISS (Keep It Stupid & Simple).

[hugel]

Flap handle. Should be kept for backup only and a new logic incorporated in speed modes allowing flaps extension for slowing down. EGPWS will yell at you TOO LOOW GEAR/FLAPS but no piece of automation here...still manually have to lower the gear. Even 3 radio altimeters not sufficent to tell that we can safely raise the gear automatically. We have auto slats but no auto flaps. You have raised some very interesting points. The one I have quoted above is another instance of the Automation vs Control debate. Not everything can be developed from the pilots’ use-case. Redundancy, reversion and BITE data-validity checking may be going on of which you are not aware. What level of abstraction is reasonable ? At what level would you want to interrupt the automation workflow if a fault develops (assuming it is safe to do so) ?

The important thing is to avoid latent failures. It is very difficult to establish the impact of partial loss of inputs to a complex system, in order to allow continued operation. Which functionality of the equipment is still OK ? It is safer to declare the unit non-functional and switch to an alternative. So I agree a “partially failed” indication as mentioned elsewhere in your post is not very helpful !


It is very complicated for a pilot to write down a robust spec to an engineer.
It is very easy for the engineer to implement the IF ...CONDITION then ACTION from the spec, but it is awfully complicated to write a ELSE if nothing is given in the spec.

Most of the problems are coming for this missing statement (unspecified). And it is getting worse because of commercial pressure( shorter coding, testing, integration, robustness test time), more and more combination of conditions are remaining untested or deliberately put into the class "unlikely to occur".
It is not possible to cover testing of all combinations of input scenarios, but the classification DO-178B (Airborne Software Considerations) identifies categories of software an applicable levels and type of testing required. A hazard-analysis bottom-up (what-if ?) and a Fault Tree top-down (what-could-cause-this-top-level-event ?) should cover hazardous events and identify mitigation to reduce to risk of the outcome.

Getting users, even highly trained and intelligent-ones like pilots (!) to express their requirements is difficult and is often based on “I want it like this - but better”. It needs to be related to a specific aspect of an existing system of an available prototype to demonstrate the concept.


I would be interested to know your views of data-fusion, and integration of equipmnet displays and data sources.


hugel

[FlightDetent]

I understand the thread moved past this particular item, but perhaps someone may still find little info on the horizon interesting. The part number is LUN 1202, electrically powered through voltage changer. Best picture I could find is here:

http://pwdt.virtualskies.net/images/lun1202.jpg

Used on 70's design eastern trainers (Zlins), simple design now obsolete. I completed my initial instrument and night training with these.

The mechanical principles are:
Aircraft symbol is fixed in bank. The left knob serves for adjustments in pitch designed to fine tune the vertical position of the aircraft symbol so that in level flight with different speeds pilot could "zero" the indicated pitch and maintain precise reference. I was told not to use it, nor felt it would be required.

The coloured ball inside (not the side-slip indicator) maintains position in 3D with the vertical divider aligned to true horizon.

How to read:

The picture shows a slight nose down attitude, for basic recognition the upper part over which the aircraft symbol is now portrayed is painted brown with a label "descends". Suppose you would like to return to neutral pitch: look at the ball's vertical divider and "pick" it up to align with (fixed) aircraft symbol. The ball's divider needs to go up - pull back on the stick.

Bank is read by comparing the top-down line on the ball to the scales at bottom. The gyro-ball is again stabilised and the whole instrument (and aeroplane) revolves around it. For a right 15 deg bank situation, the scales would turn clockwise over the stabilised background gyro ball. I.e. you need to pull the top-down line drawn on the gyro-ball out from the neutral position behind the scales to the first mark on the right side. As you apply right rudder to keep the sideslip indicator centred you will see the turn coordinator located right in between these to sway to right, all conveniently located at one spot. So once we had banked to the right you would see the top-down line on the reference ball aligned behind the right side of the (fixed) scales on the bottom of the instrument. To return wings level, you push the top-down line back to centre with a left input on the stick. Or, as I was told on the first day of the training "kick" the gyro back to neutral position - with your knee kick the stick.

Maybe different teaching would be required with yoke equipped aircraft, but for Zlins this worked seamlessly.

Yours,
FD (the un-real)