EC155 incident, SNS, 6 Nov 2013
they operate with 1 pilot and 1 flight engineer
It would be a better mix than the current arrangement.
1 x Human Pilot - check
1 x Autopilot - check
1 x Engineer who actually knows what is going on - check
= Happy days
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HC - Thank you for your last post. However we were discussing optimum use of the Autopilot. Whilst I enjoyed your mild rant about the console HMI we cannot fix everything in one day or track all those issues on one thread.
Come and see me and I will show you very graphically why flying manually with GA deployed can lead to very unsafe flight paths!
FYI - 14k offshore in S61, 322, 332L2 and EC225. No OPSAR but I do help SAR pilots to transition to the EC225 SAR. Your description of pressing the FTR in HOV or GSPD modes is flawed. Again I will show you why.
HC - pressing the FTR is not the optimum way to make a turn unless flying NOE military style. Not sure if you have any experience of military applications. However the best way in offshore environment is to do it coupled with HDG when a heading is required. The alternative to this is to trim into the turn. This works very well in mixed mode as it does not interfere with the longitudinal channal and whatever is installed thereon. Pressing the FTR is an acceptable practice during a VMC approach in the latter stages where trimming is no longer happening fast enough. This subject is. Two hour brief and flight in SIM 1 of our syllabus. Specifically to get these concepts hammered home before anything else. The 5 methods f operating in ATT, hoe to do each one and when each is appropriate. Systems approach to flight training.
DB
DB
Come and see me and I will show you very graphically why flying manually with GA deployed can lead to very unsafe flight paths!
FYI - 14k offshore in S61, 322, 332L2 and EC225. No OPSAR but I do help SAR pilots to transition to the EC225 SAR. Your description of pressing the FTR in HOV or GSPD modes is flawed. Again I will show you why.
HC - pressing the FTR is not the optimum way to make a turn unless flying NOE military style. Not sure if you have any experience of military applications. However the best way in offshore environment is to do it coupled with HDG when a heading is required. The alternative to this is to trim into the turn. This works very well in mixed mode as it does not interfere with the longitudinal channal and whatever is installed thereon. Pressing the FTR is an acceptable practice during a VMC approach in the latter stages where trimming is no longer happening fast enough. This subject is. Two hour brief and flight in SIM 1 of our syllabus. Specifically to get these concepts hammered home before anything else. The 5 methods f operating in ATT, hoe to do each one and when each is appropriate. Systems approach to flight training.
DB
DB
Last edited by DOUBLE BOGEY; 20th Jul 2014 at 07:56.
Resorting to the red inserts!
HC - Thank you for your last post. However we were discussing optimum use of the Autopilot. Whilst I enjoyed your mild rant about the console HMI we cannot fix everything in one day or track all those issues on one thread.
We were also discussing the OEM's input to creating operating procedures and I was illustrating why that was fraught. The AH-F guys at the conference (Gilles and Rupert) fully agree with me.
Come and see me and I will show you very graphically why flying manually with GA deployed can lead to very unsafe flight paths!
Flying manually with GA deployed can cause an unsafe flight path, as the thread subject clearly shows, but only if the FTRs are not depressed on cyclic and collective. If your simulator can show me that your above statement is true with the FTRs depressed, then there is something wrong with your simulator.
FYI - 14k offshore in S61, 322, 332L2 and EC225. No OPSAR but I do help SAR pilots to transition to the EC225 SAR.
Yes I know you have lots of experience, I was just unsure whether you had left CHC before flying the 225 operationally.
Your description of pressing the FTR in HOV or GSPD modes is flawed. Again I will show you why.
OK things are getting a bit complicated here but I never said to fly HOV or GSPD (or GTC) with the FTR pressed. I said they were routinely flown-through - (without pressing FTR, sorry I didn't specify that) - in those modes the FTR can have another function eg setting the datum groundspeed to the current groundspeed. Just re-reading my previous post I have put a sentence into grey since it is not really the full picture, but the full picture is a bit too complicated to explain here.
HC - pressing the FTR is not the optimum way to make a turn unless flying NOE military style. I disagree in the case of visual manoeuvring to takeoff or land, or during an autorotation entry - which are just about the only times you would want to fly it manually. (once settled in Auto, select IAS mode!)
Not sure if you have any experience of military applications. None However the best way in offshore environment is to do it coupled with HDG when a heading is required. I agree, if you want to fly it using the automation, but we are surely talking about the case where you don't? The alternative to this is to trim into the turn. This works very well in mixed mode as it does not interfere with the longitudinal channal and whatever is installed thereon. Too slow and clumsy - much better to use HDG beeped by cyclic trim. If there is a concern about maintaining the longitudinal attitude (night, poor vis etc) one should coupled 4 axis. Pressing the FTR is an acceptable practice during a VMC approach in the latter stages where trimming is no longer happening fast enough. So we are pretty much in agreement, it is just a matter of what you mean by the latter stages!
This subject is. Two hour brief and flight in SIM 1 of our syllabus. Specifically to get these concepts hammered home before anything else. The 5 methods f operating in ATT, hoe to do each one and when each is appropriate. Systems approach to flight training.
Agreed. Of course all our early convertees were diff course ex 332L /L2 so much of the trimming concepts carry over, but when I wrote the type rating course for the new recruits we certainly had to add a big chunk on the basics of the various trimming techniques. You can't progress until you have mastered that bit!
DB
DB
We were also discussing the OEM's input to creating operating procedures and I was illustrating why that was fraught. The AH-F guys at the conference (Gilles and Rupert) fully agree with me.
Come and see me and I will show you very graphically why flying manually with GA deployed can lead to very unsafe flight paths!
Flying manually with GA deployed can cause an unsafe flight path, as the thread subject clearly shows, but only if the FTRs are not depressed on cyclic and collective. If your simulator can show me that your above statement is true with the FTRs depressed, then there is something wrong with your simulator.
FYI - 14k offshore in S61, 322, 332L2 and EC225. No OPSAR but I do help SAR pilots to transition to the EC225 SAR.
Yes I know you have lots of experience, I was just unsure whether you had left CHC before flying the 225 operationally.
Your description of pressing the FTR in HOV or GSPD modes is flawed. Again I will show you why.
OK things are getting a bit complicated here but I never said to fly HOV or GSPD (or GTC) with the FTR pressed. I said they were routinely flown-through - (without pressing FTR, sorry I didn't specify that) - in those modes the FTR can have another function eg setting the datum groundspeed to the current groundspeed. Just re-reading my previous post I have put a sentence into grey since it is not really the full picture, but the full picture is a bit too complicated to explain here.
HC - pressing the FTR is not the optimum way to make a turn unless flying NOE military style. I disagree in the case of visual manoeuvring to takeoff or land, or during an autorotation entry - which are just about the only times you would want to fly it manually. (once settled in Auto, select IAS mode!)
Not sure if you have any experience of military applications. None However the best way in offshore environment is to do it coupled with HDG when a heading is required. I agree, if you want to fly it using the automation, but we are surely talking about the case where you don't? The alternative to this is to trim into the turn. This works very well in mixed mode as it does not interfere with the longitudinal channal and whatever is installed thereon. Too slow and clumsy - much better to use HDG beeped by cyclic trim. If there is a concern about maintaining the longitudinal attitude (night, poor vis etc) one should coupled 4 axis. Pressing the FTR is an acceptable practice during a VMC approach in the latter stages where trimming is no longer happening fast enough. So we are pretty much in agreement, it is just a matter of what you mean by the latter stages!
This subject is. Two hour brief and flight in SIM 1 of our syllabus. Specifically to get these concepts hammered home before anything else. The 5 methods f operating in ATT, hoe to do each one and when each is appropriate. Systems approach to flight training.
Agreed. Of course all our early convertees were diff course ex 332L /L2 so much of the trimming concepts carry over, but when I wrote the type rating course for the new recruits we certainly had to add a big chunk on the basics of the various trimming techniques. You can't progress until you have mastered that bit!
DB
DB
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HC - I knew we were basically on the same page but I jumped in because you gave CYCLIC the impression that flying with the FTR pressed is the correct way to fly. It is only appropriate VMC, when all the other more stable methods are not happening fast enough! I think we have agreed that! Which is actually what I implied in my list of priorities.
DB,
We do not have another thread for the HMI issues and so we should not shrug it aside so quickly. Without moving off the fence with respect to the very interesting discussion that you have been having with HC (clearly the context should have been set out at the start); his point on the radios were with respect to the fact that they were set up by the OEM for their own mode of operations (single pilot and not offshore - where the PM makes all selections).
That's an important but minor point so here is another probably more important one:
Below are two 'approved' implementations of the 'predicted altitude function' of the autopilot. Examine these examples and imagine 'the eye positions', 'the hand positions' and 'the amount of distraction' in completing the operation.
The second implementation doesn't escape without criticism however because, on the FCP the 'IAS' is on the left of the row of controls but on the FMA, it is on the right. A classic example of poor 'mapping' as described in Don Norman's book - 'The Design of Everyday Things'.
Jim
We do not have another thread for the HMI issues and so we should not shrug it aside so quickly. Without moving off the fence with respect to the very interesting discussion that you have been having with HC (clearly the context should have been set out at the start); his point on the radios were with respect to the fact that they were set up by the OEM for their own mode of operations (single pilot and not offshore - where the PM makes all selections).
That's an important but minor point so here is another probably more important one:
Below are two 'approved' implementations of the 'predicted altitude function' of the autopilot. Examine these examples and imagine 'the eye positions', 'the hand positions' and 'the amount of distraction' in completing the operation.
- Go to the Display Control Panel (DCP – on the central panel), select the ALTP position on the rotary switch, pull and turn the central adjustment knob whilst watching the digital indicator on the PFD (above the altimeter); once the correct number has been selected, go to the Mode Selector Panel (MSP – on the instrument panel) and press the soft-key with ALTP under it; check on the MSP screen (a) that it is armed; and (b) that this is reflected in the Mode Selection Annunciator (MSA) on the PFD.
- Go to the Flight Control Panel (FCP – on the instrument panel immediately below the FND) find and use the ALT.A knob to select the altitude on the PFD whilst watching the digital indicator and, when correct, push it to select whilst monitoring the indication on the MSA (all the time the eyes are on the FND after locating the correct knob on the FCP).
The second implementation doesn't escape without criticism however because, on the FCP the 'IAS' is on the left of the row of controls but on the FMA, it is on the right. A classic example of poor 'mapping' as described in Don Norman's book - 'The Design of Everyday Things'.
Jim
Last edited by JimL; 20th Jul 2014 at 12:51.
Whilst on the subject of the HMI and mode selections, can I also just mention that as a multi-pilot helicopter it would be quite wrong to presume that the PF is the one who should be making these selections. In Bristow it was certainly "normal" to get PM to make the selections on the FCP (on the instruction of the PF of course), in part to allow such selections without PF having to take his hands away from the controls at low altitude, leaning forward and risking catching the cyclic with a fingers destined for FCP buttons (yup, happened to me a few times!) and in part because it fosters a feeling of involvement for PM (relevant especially if he is the co-pilot). Obviously the PF could also make such selections especially if the PM was busy with radio, paperwork etc, but it seems good MCC practice to involve both pilots in controlling the flight path where appropriate. And all associated with the correct verbal procedures for use of automation of course.
And another thing!... In defence of the thread subject crews repeated resetting of the AFCS and then expecting it to work but perhaps with some seeds of doubt, what isn't covered is to what extent such resetting was commonplace. Sometimes we end up living with nuisances such as having to routinely reset things that we really shouldn't have to do, in the case of the L2 for example accepting a flashing GOV for departure when we really shouldn't do. These things shouldn't happen but in the real world they do, due to inertia caused by other more pressing things to be fixed, cost, or the daunting task of getting any fixes past EASA.
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HC - I knew we were basically on the same page but I jumped in because you gave CYCLIC the impression that flying with the FTR pressed is the correct way to fly. It is only appropriate VMC, when all the other more stable methods are not happening fast enough! I think we have agreed that! Which is actually what I implied in my list of priorities.
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Something I seem to be hearing is Co-Pilots may have been utilized to do all the Grunt Work, while the Captain did the flying.
That does not mean the Coey's never fly or rarely fly, but does it pose a question as to who should be doing the flying and who should be doing the Monitoring, and under the current Industry Environment we have it wrong way around.
Would that one change, letting the Co-Pilot do the majority of the hands on flying with the Captain pushing the buttons and making the radio calls and thus being free to devote his full attention to ensuring the Flight is being done as best possible not be the better approach to business?
That does not mean the Coey's never fly or rarely fly, but does it pose a question as to who should be doing the flying and who should be doing the Monitoring, and under the current Industry Environment we have it wrong way around.
Would that one change, letting the Co-Pilot do the majority of the hands on flying with the Captain pushing the buttons and making the radio calls and thus being free to devote his full attention to ensuring the Flight is being done as best possible not be the better approach to business?
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Oh dear now I find myself agreeing more with DB's earlier post, I would only use FTR in VMC when wanting to make control movements which would be uncomfortable or feel "unstable" any other way. I don't have much 225 time but the latter stages of a VMC approach would be typical.
In practice, I expect that I subconsciously have used a combination of all techniques at different times during a VMC approach or other VMC manoeuvre without necessarily thinking about exactly which control movement uses which technique. However, coming from types which didn't have as much wonderful automation, I found myself using it to its maximum at every opportunity when I could.
In practice, I expect that I subconsciously have used a combination of all techniques at different times during a VMC approach or other VMC manoeuvre without necessarily thinking about exactly which control movement uses which technique. However, coming from types which didn't have as much wonderful automation, I found myself using it to its maximum at every opportunity when I could.
Something I seem to be hearing is Co-Pilots may have been utilized to do all the Grunt Work, while the Captain did the flying.
That does not mean the Coey's never fly or rarely fly, but does it pose a question as to who should be doing the flying and who should be doing the Monitoring, and under the current Industry Environment we have it wrong way around.
Would that one change, letting the Co-Pilot do the majority of the hands on flying with the Captain pushing the buttons and making the radio calls and thus being free to devote his full attention to ensuring the Flight is being done as best possible not be the better approach to business?
That does not mean the Coey's never fly or rarely fly, but does it pose a question as to who should be doing the flying and who should be doing the Monitoring, and under the current Industry Environment we have it wrong way around.
Would that one change, letting the Co-Pilot do the majority of the hands on flying with the Captain pushing the buttons and making the radio calls and thus being free to devote his full attention to ensuring the Flight is being done as best possible not be the better approach to business?
I wouldn't like to see Cos doing most of the flying - Capts have to maintain currency too and as has recently been repeatedly demonstrated, it is often when the Capt has been flying that disaster has struck or nearly so.
Sharing of flying didn't appear to be an issue worthy of discussion at the conference but there was on the best allocation of resources in instrument approaches (incidentally, the presenter was one of the line pilots present):
As HC has said, with offshore approaches the PF/PM allocation is usually governed by the side of the platform to which the approach is being flown.
Jim
Captain Colin Milne, using two recent accidents as case studies, explained how the lack of specific procedures and prescribed use of existing automation, had resulted in the aircraft being placed into a situation where recovery had not been possible. He also brought attention to the fact that, in many of the accidents/incidents experienced in the North Sea, the PIC was PF and the SIC, PM; this was contrary to the practice in the airlines where the more experienced pilot assumed the monitoring role - ready to advise corrections or, in extremis, to take control.
Jim
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Yes, but.....Milne saw fit to bring it up for some reason.
Offshore may present situations where adopting the Airline method is not possible but then when returning ashore there should be absolutely no hinderance in adopting the Airline Model should it?
Offshore may present situations where adopting the Airline method is not possible but then when returning ashore there should be absolutely no hinderance in adopting the Airline Model should it?
There isn't, but what's your point? In the one flight, it was probably determined to be the capt's landing offshore due to wind direction and rig orientation, in the other we all agree that it would have been better if Co had been flying the approach, but for P2 to do so is not verboten - after all Cos have to get some experience in the Capt's role before assuming command. It was a command decision to deviate from normal practice, one which he no doubt now strongly regrets.
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IMO it would be wrong to adopt any "absolutes" in aviation. And as far as I'm concerned the drive to adopt much of the FW procedures into RW flying is too much as it is. It's just not quite the same type of flying. But you have to know what you're doing. Probably a reason why NASA managed to train monkeys to fly FW but not helicopters yet..
The PIC needs to ensure he/she does not get overloaded. It may mean to take on the PM role and let the SIC get on with it, or take on the PF role if that means an acceptable workload.
As far as training is concerned I advocate understanding and knowledge of aircraft systems as well as environment. Doing anything by rote will become a liability on that one day that you should have stayed in bed.
To ensure that one needs currency in both roles. And never underestimate the learning effect of a good debrief, for both PIC and SIC.
The PIC needs to ensure he/she does not get overloaded. It may mean to take on the PM role and let the SIC get on with it, or take on the PF role if that means an acceptable workload.
As far as training is concerned I advocate understanding and knowledge of aircraft systems as well as environment. Doing anything by rote will become a liability on that one day that you should have stayed in bed.
To ensure that one needs currency in both roles. And never underestimate the learning effect of a good debrief, for both PIC and SIC.
The Impending Issue
An excellent discussion is going on here, and I am wondering if any of the various operator groups have begun thinking about what they expect out of imminent fly by wire technology?
S76Heavy,
We must not fall victim to a misunderstanding here; when considering how to deal with the introduction of automation, it would be wrong not to consider how others coped with the change from 'control of flight' to 'management of flight' - in Professor Boy's description the 'first revolution'. This was recognised at the conference and characterised as follows:
The general mood at the conference was that we are - as an industry - insular and had not taken note of the effect of the introduction of automation to the fixed-wing world. This was summed up as follows:
With respect to the observations of Colin Milne, they were in the context of his presentation ‘Achieving Common (Best Practice) Operational Standards’. In my view it was a cogent observation - particularly in the light of the interim report on the Sumburgh accident - that the majority of automation accidents/incidents occurred when the PIC was acting as PF. What he might have mentioned was that this was also the fact in the Cougar 851 incident - which led to observations about this by the Canadian AIB.
To call the Captain's monitored approach a fixed-wing practice is to miss the point; where 'onshore' instrument approaches are being conducted, there is virtually no difference between fixed-wing and helicopters. If a risk assessment by the airlines had established that Captain's monitored approach was a safer practice, we would be foolish not to assess whether that might be the case for us as well.
Also with regard to Sumburgh, there did not appear to be good (or even any) SOPs with respect to the use of automation and, in particular, mixed mode flying. That appears now to be in the process of rectification as is the issue of stable approaches.
We are also in the process of establishing what monitoring might mean with the advent of automation. That this appears to be more complex than at first imagined was evidenced by an interesting presentation by Steve Jarvis; Steve didn't leave his presentations for us to examine but my observations were as follows:
John,
I think it is fair to say that industry are filled with trepidation about the transition to fly-by-wire. In fact the wake-up call that now appears to be motivating the industry to examine the current situation, with respect to automation, will hopefully result in effective processes in managing change in the future.
Perhaps this might start with the regulators who should examine their stance with respect to the certification of exotic systems. Although there is now guidance with respect to fly-by-wire, we are still missing the rule/guidance xx.1329 Flight Guidance Systems.
If anything, the introduction of fly-by-wire strengthens the case for close oversight of the design process. However, we are bedevilled by the perennial problem that the knowledge is mostly restricted to the manufacturers.
Jim
We must not fall victim to a misunderstanding here; when considering how to deal with the introduction of automation, it would be wrong not to consider how others coped with the change from 'control of flight' to 'management of flight' - in Professor Boy's description the 'first revolution'. This was recognised at the conference and characterised as follows:
Necessary changes required in piloting skills when converting from flying with basic instruments and stabilisation, to managing the on-board systems, have not been fully recognised and implemented; there was ample evidence that the necessity for managed transition had not been understood (by regulators or operators) or put in place.
...we have not aligned ourselves closely enough with our fixed-wing colleagues and we do not, even when offered the opportunity, participate in many of the work-streams. In fact we have actively fed the myth that Rotary is different from Fixed-Wing because it is more flexible but, there is extensive evidence that in SAR, HEMs, Offshore and Onshore Operations, the flight-path and automation management principles look pretty similar to those in aeroplanes.
To call the Captain's monitored approach a fixed-wing practice is to miss the point; where 'onshore' instrument approaches are being conducted, there is virtually no difference between fixed-wing and helicopters. If a risk assessment by the airlines had established that Captain's monitored approach was a safer practice, we would be foolish not to assess whether that might be the case for us as well.
Also with regard to Sumburgh, there did not appear to be good (or even any) SOPs with respect to the use of automation and, in particular, mixed mode flying. That appears now to be in the process of rectification as is the issue of stable approaches.
We are also in the process of establishing what monitoring might mean with the advent of automation. That this appears to be more complex than at first imagined was evidenced by an interesting presentation by Steve Jarvis; Steve didn't leave his presentations for us to examine but my observations were as follows:
Doctor Steve Jarvis showed how, by taking different perspectives on any subject, opposite conjectures can be shown to be correct. Even such well used phrases such as ‘situational awareness’ mean different things depending upon context; the crew need to have ‘awareness’ of where they are in the patterns of an instrument approach but also need ‘awareness’ of the current parameters of the flight (and might be ‘aware’ in one but not the other). Understanding that situational awareness is a multi-level concept will have an effect on the roles specified for the crew members and the subsequent division of labour and responsibility.
The roles of pilots in managing and monitoring are more complex than first imagined and simplistic views of what solutions may be required are often misguided. Monitoring for example has always been problematical because it is difficult to know what is being viewed, and when...
The roles of pilots in managing and monitoring are more complex than first imagined and simplistic views of what solutions may be required are often misguided. Monitoring for example has always been problematical because it is difficult to know what is being viewed, and when...
I think it is fair to say that industry are filled with trepidation about the transition to fly-by-wire. In fact the wake-up call that now appears to be motivating the industry to examine the current situation, with respect to automation, will hopefully result in effective processes in managing change in the future.
Perhaps this might start with the regulators who should examine their stance with respect to the certification of exotic systems. Although there is now guidance with respect to fly-by-wire, we are still missing the rule/guidance xx.1329 Flight Guidance Systems.
If anything, the introduction of fly-by-wire strengthens the case for close oversight of the design process. However, we are bedevilled by the perennial problem that the knowledge is mostly restricted to the manufacturers.
Jim
Hi John,
Unfortunately you are correct; the ARAC committee was tasked on 11 April 2014 - up to that time it is still special conditions (what is not fly-by-wire in the airline and advanced corporate jets these days?).
The guidance that I saw was general and contained in AC 25.1329 (and in various other rules/guidance in Part 25). Strangely enough, EASA have seven references to fly-by-wire in AMC No.1 to CS 25.1329 as opposed to four in AC 25.1329.
Begs the question I asked before: what is being used for certification of FGSs? I have also just noticed the reference in AMC 25.1329 to manufacturers' FCOMs ("The normal procedures for use of the FGS should be documented in the AFM or FCOM, as appropriate. These procedures should be demonstrated during the type certification process.").
Why don't we split this subject off into another thread and see what views turn up? I would be interested in whether Bell are prepared to comment on their system for the Relentless.
Jim
Unfortunately you are correct; the ARAC committee was tasked on 11 April 2014 - up to that time it is still special conditions (what is not fly-by-wire in the airline and advanced corporate jets these days?).
The guidance that I saw was general and contained in AC 25.1329 (and in various other rules/guidance in Part 25). Strangely enough, EASA have seven references to fly-by-wire in AMC No.1 to CS 25.1329 as opposed to four in AC 25.1329.
Begs the question I asked before: what is being used for certification of FGSs? I have also just noticed the reference in AMC 25.1329 to manufacturers' FCOMs ("The normal procedures for use of the FGS should be documented in the AFM or FCOM, as appropriate. These procedures should be demonstrated during the type certification process.").
Why don't we split this subject off into another thread and see what views turn up? I would be interested in whether Bell are prepared to comment on their system for the Relentless.
Jim
Jim,
did you spot BB's thread earlier about the B525 testing?
Link to the article here: 'Flight Testing' the Bell 525 Relentless | Vertical Magazine - The Pulse of the Helicopter Industry
An interesting extract here, with insights into the certification demands not keeping up (my bold):
I'm curious about how many layers of redundency there will be and, therefore, how many levels of control law that may be 'available' - most FW FBW have Normal, Alternate and Direct laws plus mechanical back-up (for temporary control). If we have a cyclic that becomes a translational rate controller rather than an attitude controller, how readily can a pilot revert to primary effects of controls principles if he finds himself in Direct law on a dark night? The 'resilience' concept re-appears......
did you spot BB's thread earlier about the B525 testing?
Link to the article here: 'Flight Testing' the Bell 525 Relentless | Vertical Magazine - The Pulse of the Helicopter Industry
An interesting extract here, with insights into the certification demands not keeping up (my bold):
The biggest change I noted was that the flight controls now have “tactical cues” when limits are reached. When Caudill had me pull the collective to a power limit, it increased the pull force — giving me adequate warning and time to correct. The cyclic will give a similar warning when Vne (never exceed speed) is approached.
The cyclic also has a trim follow-up feature in both fore and aft, as well as lateral modes. The trim follow-up feature is available throughout the entire envelope except when in Translational Rate Command (TRC). Here, the envelope is ½ knot to 10 knots. At ½ knot or below, position hold becomes active. Put the helicopter where you want it, and leave it alone. The pilot displaces the cyclic to get the desired speed, or he can beep for the change. Groundspeed from beeping is dependent on altitude: 10 feet and below you get 1 knot; 20 to 11 feet, 2 knots; and so on to 50 feet, which gives you 5 knots. You can’t beep out of TRC.
Since my first visit, Bell changed the trim follow up in longitudinal axis to return to trim. However, TRC is still available in the lateral axis. Therefore, any acceleration or deceleration if not re-trimmed will return to previously trimmed air/groundspeed. For example, if the helicopter is trimmed to 130 knots and decelerated to 50 knots without re-trimming, the helicopter will slowly accelerate back to 130 knots when the cyclic is returned to detent or the displacement is taken out. The same goes for an acceleration. “I wouldn’t say this was the only reason we made the change to longitudinal axis, but it cleans up the control laws and enables us to meet the FAR requirement of ‘Positive Longitudinal Static Stability,” said Caudill.
The cyclic also has a trim follow-up feature in both fore and aft, as well as lateral modes. The trim follow-up feature is available throughout the entire envelope except when in Translational Rate Command (TRC). Here, the envelope is ½ knot to 10 knots. At ½ knot or below, position hold becomes active. Put the helicopter where you want it, and leave it alone. The pilot displaces the cyclic to get the desired speed, or he can beep for the change. Groundspeed from beeping is dependent on altitude: 10 feet and below you get 1 knot; 20 to 11 feet, 2 knots; and so on to 50 feet, which gives you 5 knots. You can’t beep out of TRC.
Since my first visit, Bell changed the trim follow up in longitudinal axis to return to trim. However, TRC is still available in the lateral axis. Therefore, any acceleration or deceleration if not re-trimmed will return to previously trimmed air/groundspeed. For example, if the helicopter is trimmed to 130 knots and decelerated to 50 knots without re-trimming, the helicopter will slowly accelerate back to 130 knots when the cyclic is returned to detent or the displacement is taken out. The same goes for an acceleration. “I wouldn’t say this was the only reason we made the change to longitudinal axis, but it cleans up the control laws and enables us to meet the FAR requirement of ‘Positive Longitudinal Static Stability,” said Caudill.