Minimas on Non Precision Approaches
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In future I think i'll just be more careful with how I word my questions. Ultimately I was thinking that NPA minimas are set so as to position your bus overhead a certain point and allow you to continue with the approach from normal circuit height or otherwise bug out.
But say you're flying your own aircraft under your own insurance policy without any passengers on board to a strip without surrounding people or property and you've got no family or friends who care about you, you're feeling a little suicidal and you've got no personal hangups about dying in the cockpit on this particular flight. Now that we've eliminated all your ethical concerns, is there anyone who's actually prepared to discuss the technicalities, pitfalls and feasability of creating your own minimas, or does your ability not extend further than reciting verse from textbooks and quoting rules we're all well aware of?
In much the same vein as the limits applied to aircraft, so minimias have a certain tolerance built in to them (eg a cessna won't actually break up in mid air under a G-loading of +3.81). So what I want to discuss is what factors you'd include to calculate the real and absolute minima for a particular approach.
Moreover, i'd maintain that alot of those who did die in CFIT accidents made the decision to go below minima without ever having a technical discussion about it's dangers while they were on the ground, and after getting into a situation where they were faced with the decision and deciding to take the risk under the pretence that there was SOME level of tolerance without knowing exactly how much, they pushed through what you might call the yellow arc and ended up in the red.
What is so wrong about discussing the grey area? Telling someone the usual drawl that 'lots of people have died in this way so don't go beyond here because that's wrong' isn't an effective way of ensuring people stick to limits. If it were people wouldn't keep dieing in this way. What is effective is educating people so you satisfy their curiosities and circumvent their tendancy to go exploring.
But say you're flying your own aircraft under your own insurance policy without any passengers on board to a strip without surrounding people or property and you've got no family or friends who care about you, you're feeling a little suicidal and you've got no personal hangups about dying in the cockpit on this particular flight. Now that we've eliminated all your ethical concerns, is there anyone who's actually prepared to discuss the technicalities, pitfalls and feasability of creating your own minimas, or does your ability not extend further than reciting verse from textbooks and quoting rules we're all well aware of?
In much the same vein as the limits applied to aircraft, so minimias have a certain tolerance built in to them (eg a cessna won't actually break up in mid air under a G-loading of +3.81). So what I want to discuss is what factors you'd include to calculate the real and absolute minima for a particular approach.
Moreover, i'd maintain that alot of those who did die in CFIT accidents made the decision to go below minima without ever having a technical discussion about it's dangers while they were on the ground, and after getting into a situation where they were faced with the decision and deciding to take the risk under the pretence that there was SOME level of tolerance without knowing exactly how much, they pushed through what you might call the yellow arc and ended up in the red.
What is so wrong about discussing the grey area? Telling someone the usual drawl that 'lots of people have died in this way so don't go beyond here because that's wrong' isn't an effective way of ensuring people stick to limits. If it were people wouldn't keep dieing in this way. What is effective is educating people so you satisfy their curiosities and circumvent their tendancy to go exploring.
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BSQ... given the scenario that you've just described, why would you even bother having any sort of minima? Perhaps I'm missing something here but what can we possibly learn from such a situation? Surely we should already have learned more from real world prangs?
Every Pans Ops and TERPs approach procedure provides the very best DA or MDA that is possible. Speaking as a procedure designer with many years of experience in the field, I can assure you that we don't try to make a minima any higher than it needs to be. Therefore, if you CHOOSE to bust the minima, you're trusting your luck, your skill and your equipment.
If any one of those isn't working well on the day, the result isn't going to be very pretty.
Every Pans Ops and TERPs approach procedure provides the very best DA or MDA that is possible. Speaking as a procedure designer with many years of experience in the field, I can assure you that we don't try to make a minima any higher than it needs to be. Therefore, if you CHOOSE to bust the minima, you're trusting your luck, your skill and your equipment.
If any one of those isn't working well on the day, the result isn't going to be very pretty.
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Moreover, i'd maintain that alot of those who did die in CFIT accidents made the decision to go below minima without ever having a technical discussion about it's dangers while they were on the ground, and after getting into a situation where they were faced with the decision and deciding to take the risk under the pretence that there was SOME level of tolerance without knowing exactly how much, they pushed through what you might call the yellow arc and ended up in the red.
What is so wrong about discussing the grey area?
OzExpat:
Finally, a TERPs nerd! My understanding of TERPs criteria is limited to that which may be gleaned from studying and flying IAPs. A sort of reverse engineering. Toss in a few articles on the subject of obstacle clearance planes or circling radii and protection zones and voila! A latent TERPs nerd has been created. The more I learn about it, the more I am convinced of the truth of your statement:
BQS:
Even though a certain margin for error is required to be built in to every procedure in the form of required width and shape of protection zones and minimum vertical obstacle clearance, the margin can disappear quite easily if maximum allowable navigational accuracy deviation or altimetry discrepancy errors are compounded by ANY deviation by the pilot from indicated course centerline or descent below MDA without visual reference. Most critical at high mountain airports where TAS is higher and altimetry errors are compounded by strong local variations in wind direction/velocity and barometric pressure. You only need to fly these approaches to minimums in real low weather a few times to begin to appreciate the importance of approach design standards and a defined missed approach path with sufficient obstacle protection.
The cumulus granititus just sit and wait for the errant pilot to come to them. The object of the exercize is to fly the procedures as accurately as possible and adjust the MINIMUMS upward if warranted by pilot or equipment accuracy concerns, wx conditions, performance considerations or if there is any other reason to doubt the wisdom of descending all the way to mins.
I find that in most cases, proper planning and preparation for approach justifies a descent to mins on NPAs. Circling maneuvers will only be performed if preparations are made prior to commencing the approach. Low visibility is much more challenging than a low ceiling with good vis beneath. PAs make a big difference here. If I really HAD to get the airplane on the ground NOW, I'd shoot an ILS all the down if I had to. Maybe even a GPS/VNAV. I had an instrument instructor in Germany who used to have me fly all the way to the runway under the hood on a GCA or ILS. In an emergency, you do what you must or you're done. Take the best choice available. That's really what it's all about. Those who are best informed usually see more available choices. Those who are better trained and more experienced have a better chance of knowing which of the choices are better than others. Those who apply themselves 100% to the job at hand make the most of whatever quantities of the above that they possess. Those who are better prepared always seem to have more choices available and more contingency plans ready to be executed. Funny how often their primary plan seems to work out. That's what I aspire to. And a Super Cub on floats!
On the subject of people who have designed their own instrument approaches, yeah I know of a couple. Not necessarily illegal in class G airspace. Probably safe enough for them if they are conservative about it and have a good escape plan. Probably a good idea to design it as though they were going to get it approved. Only for their private use. But if anything ever goes wrong........
Best regards,
Westhawk
Finally, a TERPs nerd! My understanding of TERPs criteria is limited to that which may be gleaned from studying and flying IAPs. A sort of reverse engineering. Toss in a few articles on the subject of obstacle clearance planes or circling radii and protection zones and voila! A latent TERPs nerd has been created. The more I learn about it, the more I am convinced of the truth of your statement:
Every Pans Ops and TERPs approach procedure provides the very best DA or MDA that is possible.
Even though a certain margin for error is required to be built in to every procedure in the form of required width and shape of protection zones and minimum vertical obstacle clearance, the margin can disappear quite easily if maximum allowable navigational accuracy deviation or altimetry discrepancy errors are compounded by ANY deviation by the pilot from indicated course centerline or descent below MDA without visual reference. Most critical at high mountain airports where TAS is higher and altimetry errors are compounded by strong local variations in wind direction/velocity and barometric pressure. You only need to fly these approaches to minimums in real low weather a few times to begin to appreciate the importance of approach design standards and a defined missed approach path with sufficient obstacle protection.
The cumulus granititus just sit and wait for the errant pilot to come to them. The object of the exercize is to fly the procedures as accurately as possible and adjust the MINIMUMS upward if warranted by pilot or equipment accuracy concerns, wx conditions, performance considerations or if there is any other reason to doubt the wisdom of descending all the way to mins.
I find that in most cases, proper planning and preparation for approach justifies a descent to mins on NPAs. Circling maneuvers will only be performed if preparations are made prior to commencing the approach. Low visibility is much more challenging than a low ceiling with good vis beneath. PAs make a big difference here. If I really HAD to get the airplane on the ground NOW, I'd shoot an ILS all the down if I had to. Maybe even a GPS/VNAV. I had an instrument instructor in Germany who used to have me fly all the way to the runway under the hood on a GCA or ILS. In an emergency, you do what you must or you're done. Take the best choice available. That's really what it's all about. Those who are best informed usually see more available choices. Those who are better trained and more experienced have a better chance of knowing which of the choices are better than others. Those who apply themselves 100% to the job at hand make the most of whatever quantities of the above that they possess. Those who are better prepared always seem to have more choices available and more contingency plans ready to be executed. Funny how often their primary plan seems to work out. That's what I aspire to. And a Super Cub on floats!
On the subject of people who have designed their own instrument approaches, yeah I know of a couple. Not necessarily illegal in class G airspace. Probably safe enough for them if they are conservative about it and have a good escape plan. Probably a good idea to design it as though they were going to get it approved. Only for their private use. But if anything ever goes wrong........
Best regards,
Westhawk
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Westhawk et al - thanks for your replies. Plan on having a closer look at Pans Ops and other details on design of NPAs over the next few days and shall post any detailled questions at then.
In the meantime I had a question for OzExpat - while I don't mean to question your statement that every Pans Ops / TERPs provides the best possible MDA, while I won't be using this as a basis for in flight decision making and while I understand this may require a certain level of generalizing, what components make up an MDA? Eg is 50% for terrain clearance, 15% for equipment error, tracking error, pilot error etc etc?
In the meantime I had a question for OzExpat - while I don't mean to question your statement that every Pans Ops / TERPs provides the best possible MDA, while I won't be using this as a basis for in flight decision making and while I understand this may require a certain level of generalizing, what components make up an MDA? Eg is 50% for terrain clearance, 15% for equipment error, tracking error, pilot error etc etc?
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In the real world, there is a lot of pressure on you to get the job done. If you do not get the job done, you will be asked to explain yourself, you will have irate customers screaming at you, your chief pilot on the phone & your career on the line.
When this happens, you look at your shoulder
- and count 1-2-3-4 bars sitting there.
Now, even though the guy who hired you probably doesn't know what that means - you do! It means that you will balance all the factors in the equation, taking each into carefull consideration. You will recognise that the one paying your salary (the company) and the ones you are ultimately responsible to (your passengers & the CAA) are not the same. And you will have no doubt as to which takes the higher priority.
Your checklist will be:
1) Is it safe?
2) Is it legal?
3) Is it in the companys best interest?
4) Is it doable?
Your job as a captain is to protect the passengers and the company from themselves, you are the guardian of your passengers lives, your own license & the AoC. If you do not feel that you can balance the above factors, you should probably spend a few more months in the RHS. If you still cannot make it work, find something else to do with your life.
Remember, no matter what the passengers tell you - they often have other options for getting to their destination. And no matter what the company tells you, the profit margins are rarely that slim that one diversion will cost the company its life. Even if they do go bust - or fire you - there will be other jobs out there. If you find that the word gets around that you are not "a man who can get the job done" & that prevents you from getting other work - you are probably looking for work in the wrong circles
If there is no other work to be had - do something else with your life.
In the end, none of the big carrieres will hire you if you lack integrity or the ability to get the priorities right. They exclusively hire their future captains, not just their next F/O.
And finally - you have yourself to answer to. You take a good, long look at yourself every morning in the mirror & determine if you like that look or not. My advice is: make sure you do
Brgds fm
Empty
When this happens, you look at your shoulder
- and count 1-2-3-4 bars sitting there.Now, even though the guy who hired you probably doesn't know what that means - you do! It means that you will balance all the factors in the equation, taking each into carefull consideration. You will recognise that the one paying your salary (the company) and the ones you are ultimately responsible to (your passengers & the CAA) are not the same. And you will have no doubt as to which takes the higher priority.
Your checklist will be:
1) Is it safe?
2) Is it legal?
3) Is it in the companys best interest?
4) Is it doable?
Your job as a captain is to protect the passengers and the company from themselves, you are the guardian of your passengers lives, your own license & the AoC. If you do not feel that you can balance the above factors, you should probably spend a few more months in the RHS. If you still cannot make it work, find something else to do with your life.
Remember, no matter what the passengers tell you - they often have other options for getting to their destination. And no matter what the company tells you, the profit margins are rarely that slim that one diversion will cost the company its life. Even if they do go bust - or fire you - there will be other jobs out there. If you find that the word gets around that you are not "a man who can get the job done" & that prevents you from getting other work - you are probably looking for work in the wrong circles
If there is no other work to be had - do something else with your life.In the end, none of the big carrieres will hire you if you lack integrity or the ability to get the priorities right. They exclusively hire their future captains, not just their next F/O.
And finally - you have yourself to answer to. You take a good, long look at yourself every morning in the mirror & determine if you like that look or not. My advice is: make sure you do
Brgds fm
Empty
what components make up an MDA
aircraft speed
angle of bank
terrain clearance
obstacle density
terrain profile
weather - wind, temperature, altitude
type of navigation aid
nav. aid tolerances
nav.aid monitoring tolerances
nav. system tolerances
flight technical tolerances (accuracy, timing, bank establishment and reaction allowances)
altimetry
runway environment (visual landing aids, runway physical characteristics)
...and some others I may have missed
Post design flight inspection may reveal navigation aid performance limitations, flyability issues and charting factors.
Apart from that, it's a piece of cake.... though I think "designing" an instrument procedure without a missed approach a wee bit disconcerting ....
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Not exactly a "TERPs nerd" westhawk, more specialised in Pans Ops. However, having flown many TERPs approaches during my life to date, and having had to analyse other TERPs approaches as well, decided that the criteria wasn't intended to kill anyone. The same is certainly true of Pans Ops.
reynoldsno1... thanks for saving me on that one. I nearly choked when I saw the question.
BSQ... the only other thing that I can say after the post by my mate from New Zealand is that it's all designed to work best on a bog-standard ISA day. If you have to fly on ISA-minus days, you need to make allowances for unsafe error conditions in the altimeter indications.
reynoldsno1... thanks for saving me on that one. I nearly choked when I saw the question.
BSQ... the only other thing that I can say after the post by my mate from New Zealand is that it's all designed to work best on a bog-standard ISA day. If you have to fly on ISA-minus days, you need to make allowances for unsafe error conditions in the altimeter indications.
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Pitch up for and tell it like it is at a job interview, or even put it in your CV, - prepared to push the limits to get the job done, you can rely on me, I know what it's really like out there.
Chances of a job???????
Stay quiet, get a job. On a bad weather day, explain to your passengers that the weather is against you but not to worry, everyone else might be staying on the ground or diverting but you believe you can ignore the limits and get them there - just don't stand between them and the door.
There is one anomaly out there that I can think of - engine out allowance (EOA). My DH is 200ft agl but on a precision approach with an engine out I have to add 300ft EOA giving me a DH of 500ft. EOA doesn't apply to non-precision approaches so with a 400ft cloudbase I can get in with an engine out by using a non-precision approach but cannot shoot an ILS.
Chances of a job???????
Stay quiet, get a job. On a bad weather day, explain to your passengers that the weather is against you but not to worry, everyone else might be staying on the ground or diverting but you believe you can ignore the limits and get them there - just don't stand between them and the door.
There is one anomaly out there that I can think of - engine out allowance (EOA). My DH is 200ft agl but on a precision approach with an engine out I have to add 300ft EOA giving me a DH of 500ft. EOA doesn't apply to non-precision approaches so with a 400ft cloudbase I can get in with an engine out by using a non-precision approach but cannot shoot an ILS.
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C'mon guys i'm not a maniac and i'm not advocating this as an SOP and subsequent phallic symbol. May be this will validate the worthiness of the discussion?
Say you're doing a mercy flight - You've been to a remote area to pick up someone who's just suffered a heart attack. WX is sheight but if you don't get in they're not going to live through the flight to your alternate.....
Say you're doing a mercy flight - You've been to a remote area to pick up someone who's just suffered a heart attack. WX is sheight but if you don't get in they're not going to live through the flight to your alternate.....
Bottums Up
barbershopquartets
I'll tell you what you want to hear. Bust the minima. If you **** it up, well it won't only be th heart attack mercy recipient who dies.
It'll be you, probably any medicos who are on board, maybe the pax in the aircraft on the ground that you hit.
A hero's death.
My advice to you, is that you don't put your life, or the life of others at unnecessary risk, just to play hero. If the heart attack victim dies, so be it.
I'll tell you what you want to hear. Bust the minima. If you **** it up, well it won't only be th heart attack mercy recipient who dies.
It'll be you, probably any medicos who are on board, maybe the pax in the aircraft on the ground that you hit.
A hero's death.
My advice to you, is that you don't put your life, or the life of others at unnecessary risk, just to play hero. If the heart attack victim dies, so be it.
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Onya Clarey! That's the truth.
BSQ... The Flying Doctor, RFDS and a host of medivac mobs face the same problem. The underlying fact here is that aviation is not a universal panacea for all the ills of the world. We are first, foremost and always, professional pilots. We are not military pilots who must, on occasion, put their lives on the line for their country. We are all civilians and we all want to have a beer at the end of our working day, maybe even a hot meal if we're lucky enough to find a good (or baaaad
) woman to cook it for us! And is we're that lucky, we probably want to see her again too!
We will always... always... always (let me me repeat that... ALWAYS) do our best to get our passengers to the place they want to go. That includes patients in a medical emergency. But we will not knowingly risk our own lives, or the lives of the doctor/s, nurse/s (not to mention the F/O, of course!) or anyone else in the process.
This is not a case of the noble sacrifice, or the sacrifice of few to save... anything. And certainly not at any cost.
oldfella... are you saying that you don't have to make any adjustment in the event of a OEI go-around off a NPA?
Levelling at MDA is one thing. Climbing away at 2.5% or better is something else entirely... in some types of aircraft.
BSQ... The Flying Doctor, RFDS and a host of medivac mobs face the same problem. The underlying fact here is that aviation is not a universal panacea for all the ills of the world. We are first, foremost and always, professional pilots. We are not military pilots who must, on occasion, put their lives on the line for their country. We are all civilians and we all want to have a beer at the end of our working day, maybe even a hot meal if we're lucky enough to find a good (or baaaad
) woman to cook it for us! And is we're that lucky, we probably want to see her again too!We will always... always... always (let me me repeat that... ALWAYS) do our best to get our passengers to the place they want to go. That includes patients in a medical emergency. But we will not knowingly risk our own lives, or the lives of the doctor/s, nurse/s (not to mention the F/O, of course!) or anyone else in the process.
This is not a case of the noble sacrifice, or the sacrifice of few to save... anything. And certainly not at any cost.
oldfella... are you saying that you don't have to make any adjustment in the event of a OEI go-around off a NPA?
Levelling at MDA is one thing. Climbing away at 2.5% or better is something else entirely... in some types of aircraft.
OzExpat, I follow your well intentioned sentiments, but for the less disciplined or less experienced readers of this forum, your statements should have been reversed:
1. “We will not knowingly risk our own lives or the lives of … “
2. “We will always do our best to get our passengers to the place they want to go.”
Remember, what you write (and speak) reflects what you think. Thinking is at the centre of human assessment and decision making processes, thus in demanding situations, poor weather approaches, etc; what you have previously thought can subconsciously affect your judgement of the current situation.
--------------------
Unless specifically authorized everything else is forbidden.
1. “We will not knowingly risk our own lives or the lives of … “
2. “We will always do our best to get our passengers to the place they want to go.”
Remember, what you write (and speak) reflects what you think. Thinking is at the centre of human assessment and decision making processes, thus in demanding situations, poor weather approaches, etc; what you have previously thought can subconsciously affect your judgement of the current situation.
--------------------
Unless specifically authorized everything else is forbidden.
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Hey BSQ:
I am thankful that Westhawk has taken the time to lay it all out as he’s done, in addition to his short-and-to-the-point (and accurate) post earlier. He is right on target. Fly3 also said it well: “If you are with an outfit that accepts minima busting, go work for someone else and live to enjoy your retirement.” Please note, Fly3 did not say “...if your outfit pressures you to do it;’ he said “...if your outfit accepts pilots doing it...” If that sort of action is condoned by your outfit, you should get as far away from them as you can, as soon as you can. And, my advice is to go back and re-read Westhawk’s post above! Stay safe.
________
AirRabbit
I am thankful that Westhawk has taken the time to lay it all out as he’s done, in addition to his short-and-to-the-point (and accurate) post earlier. He is right on target. Fly3 also said it well: “If you are with an outfit that accepts minima busting, go work for someone else and live to enjoy your retirement.” Please note, Fly3 did not say “...if your outfit pressures you to do it;’ he said “...if your outfit accepts pilots doing it...” If that sort of action is condoned by your outfit, you should get as far away from them as you can, as soon as you can. And, my advice is to go back and re-read Westhawk’s post above! Stay safe.
________
AirRabbit
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alf... if I must indeed reverse the statements for the benefit of "the less disciplined or less experienced readers of this forum", then it'll probably be lost on them no matter which way I phrase it. However, I felt that I was making a point with the order in which I made those statements and I beleve that I'd considered my words quite carefully at the time. People will always read whatever they like into whatever is said on PPRuNe anyway so, in the end, we can only do the best we can in our own ways.
