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Tolka
3rd Aug 2011, 06:24
What minimum cloud ceiling do you set for yourself to allow for a landing in case of engine failure when flying IFR. For example some pilots will not fly if the base of the clouds is less than 400 feet. This is to give a better chance of a successful landing after descending through the clouds following an engine failure. Does your minimum ceiling vary depending on whether you are over water or terra firma?

Johnm
3rd Aug 2011, 06:59
I'll take off in anything legal but won't plan on going to anywhere with a forecast cloud base below 500ft and vis less than 1000 metres unless there's a nearby divert with a much better forecast.

liam548
3rd Aug 2011, 07:18
400 ft is not very long to pick a suitable landing spot in a sep. 1000ft is probably going to be my minimum.

Whopity
3rd Aug 2011, 07:45
Depends how many engines you have, and its engine out performance! SE IFR 1500 ft might give you a chance, anything below 1000 ft gives you very little chance.

IO540
3rd Aug 2011, 08:24
What minimum cloud ceiling do you set for yourself to allow for a landing in case of engine failure when flying IFR

If you are talking about overflying fog patches, OVC000 :)

The time window, enroute when the engine power settings are nice and constant, and 65% or below, is too small to worry about.

You could make the same argument about overflying forests, etc.

Tolka
3rd Aug 2011, 11:06
I'm not so much talking about fog patches as low cloud especially over water enroute in a SEP. For example, if you were flying from the UK to say Holland and you knew there was a narrow warm front over the sea but it was clear in the UK and clear in Holland. Would you undertake the flight where you intended to fly at 6,000 feet above a 4,000 layer of stratus which went down to 500 feet amsl over the sea. If not, what base would you accept. I'm just curious to get peoples views as risk acceptability varies from one person to another.

IO540
3rd Aug 2011, 11:14
Over water it doesn't matter because you are ditching anyway, so you don't need any kind of "decision height".

All you need is a few seconds' visibility of the surface so you can avoid flying into the front of a big wave.

But how will you fly at 6000 feet? On a "VFR" flight you may be illegal unless VMC on top can be assured, and on an IFR flight you will have a helluva fun getting a Eurocontrol route validated anywhere near that low down.

Also, not being a weather expert but hey I am now getting 85% on the mock JAA-crud IR Met exams, having done about 30 of them so I must know enough to fly an A330 through a CB or two :) :) :) a warm front is not going to have cloud tops (http://www.peter2000.co.uk/aviation/tops/index.html) at 4000ft. More like 24000ft, IME. 4000ft tops tend to be what you get with stratus between fronts, but the cloudbase won't be 500ft then, though it could be in the winter (with bad vis too).

what next
3rd Aug 2011, 11:18
Hello!

If not, what base would you accept. I instruct IFR in singles and twins. Our FTO has a requirement that the ceiling must be 500ft or more along the whole route. After a recent engine failure in one of our training aircraft (during the annual checkride of one of our instructors with an examiner!) I have raised this minimum to 1000ft. For me personally (or otherwise, triplicate my hourly rate...). Over water, I would probably accept 500ft, but certainly not less. In a twin I do not care too much, at least not during a training flight with only two or three occupants and no baggage. Even a Seminole can maintain 5000ft on one engine if it is not fully loaded.

Happy landings,
max

Pace
3rd Aug 2011, 11:21
You could make the same argument about overflying forests, etc.

Biggles was a master of tree landings ;) wonder what happened to him ?
Flying is all about risk management. I try never to do anything in aviation where I do not have an out. You must have other doors open to you or it all becomes a game of Russian Roulette.
Flying over extensive fog banks in a SEP is a no no in my books as in the unlikely event of an engine failure your options are closed and you are in the lap of the Gods.
A couple have posted 1000 feet agl as a sensible minimum for SEPs as that would give a reasonable chunk of VMC below to take to a field or other landing area.
Anything less and its still possible but not clever if you break out at 500 feet over an extensive built up area?
So it really depends on how much risk you are prepared to take?
I can remember a few years ago in a twin taking off from literally the only clear airfield in the uk with the whole of the UK covered in fog.
Soon after I took off even that airfield went down in fog.
Aberdeen was clear as was the whole of Ireland and I had plenty of fuel to divert to Ireland. Ok I did the trip but would not have contemplated it in a single.
So really its your own risk management and how much risk your prepared to gamble with?

Pace

IO540
3rd Aug 2011, 11:32
Flying over fog banks (for say a minute or two) is no different to landing or departing at so many airports where there are dense houses on the extended runway centrelines.

And I don't hear of airport boycotts on those grounds.

It's actually better because you are much less likely to get an engine failure in cruise (assuming you have put some juice in ;) ).

Pace
3rd Aug 2011, 11:49
10540

But that is a judgement you make? At what point do you get lured into flying over a fog bank for a minute or two to flying over extensive fog?

The minute or two easily changes to the extensive before your eyes.

The extensive especially when you know your destination is clear then becomes the NO options risk you take. The Russian roulette gamble.

Pilots take Russian Roulette gambles but it is important that we realise that as part of our decision making.

I still hold never do anything in aviation without an out!!!
An engine failure in a single no matter how unlikely over extensive dense fog gives you no other options but to hit whatever is concealed in that fog.

Pace

neilr
3rd Aug 2011, 13:09
I think I remember reading in the IFR test prep notes from the CAA that minimum cloudbase for the test to go ahead in a single is actually 1000ft (for enroute) - this seemed sensible to me so I adopted it for any SE IR that I do ...

Remember 1000ft in most singles is less then a minute and a half with no engine - that assumes a straight in approach - if you ahve to turn its even less !!

500ft ... that has been suggested is about 30-40 secs once clear of cloud

Neil

Intercepted
3rd Aug 2011, 13:21
The problem with a 1000ft+ treshold for instructors is that students never get a chance to see for real what IMC flying is about, and when it happens for real they will be on their own without an instructor in the right hand seat.

Edit: My comment relates to takeoff and approach.

what next
3rd Aug 2011, 13:47
Hello!

The problem with a 1000ft+ treshold for instructors is that students never get a chance to see for real what IMC flying is about, and when it happens for real they will be on their own without an instructor in the right hand seat.

Yes and no. That's one of the reasons why many FTOs use procedure trainers for initial IFR training. The realism of a modern training device of FNPT II standard (or better) is good enough to give the student a very realistic view of CAT 1 minima. If he wants to see those in real life, I'm happy to show him. But only in a twin. Thirty-something Euros per flying hour (or whatever the current rate for in IFR instructor may be elsewhere) is simply not enough to risk ones neck (neither would be 100 or 1000).
And then, as an instructor, if have two important obligations: One to bring myself back to my family in one piece every day and second (and even more important) to bring my student home to his family after the flight. (Piston) engines do fail from time to time. If you fly a lot (instructors do), then it is a pure matter of statistics that you will experience such failures. I have had three so far. Luckily in twins, because two were in IMC with low ceilings. Therefore, I do not take any furher chances, if there is a safe option: A simple "no"!

IO540
3rd Aug 2011, 14:00
An engine failure in a single no matter how unlikely over extensive dense fog gives you no other options but to hit whatever is concealed in that fog.Same at night :)

I don't disagree, but casting the first stone comes to mind. To acquire my various bits of paper I had to log some 10-20 hours at night, most of which was solid "no escape route" time.

I think I remember reading in the IFR test prep notes from the CAA that minimum cloudbase for the test to go ahead in a single is actually 1000ft (for enroute) - this seemed sensible to me so I adopted it for any SE IR that I do ... The examiners can specify whatever they want. They also don't fly over water in singles.

The reality is that engine failures under the circumstances discussed barely feature in the stats. Most of the stats are packed with other stuff, like CFITs, running out of juice, mismanagement of the fuel system, loss of control following structural icing, airframe breakup through flying too fast into a CB, etc.

But only in a twin

You are fortunate in that the "JAA IR = FTO" monopoly, at an eye watering £450/hour, gives you that option :)

what next
3rd Aug 2011, 14:09
...running out of juice, mismanagement of the fuel system, loss of control following structural icing...Those three can be brought to a happy ending by executing a forced landing in a field. But only, if you have the chance to select one.

BTW: I did the mandatory night flying for my own license (was ten hours then). Later I did a little instructing at night too. But once I reached 50 hours single-engine night flying (a purely arbitrary value!) I called it quits. Never again. But any time in anything with more than one engine.

You are fortunate in that the "JAA IR = FTO" monopoly, at an eye watering £450/hour, gives you that option

I wouldn't call that fortunate. Otherwise, I simply wouldn't do it. And if I look around my instructor colleaugues, there are not many who would. There are easier ways to earns one's living than instructing...

IO540
3rd Aug 2011, 21:16
It doesn't make sense to try to not fly above fog because a lot of fog is under a cloud of some sort so this would mean you can't overfly any solid cloud cover under IFR, which is silly.

Pace
3rd Aug 2011, 21:49
10540

It doesn't make sense to try to not fly above fog because a lot of fog is under a cloud of some sort so this would mean you can't overfly any solid cloud cover under IFR, which is silly.

I dont know how you do things but with me i look at met. If there is something that bothers me in the met reports I look closer.

Fog is one item that can stop me landing. Little else does. In a single I would not just look at my destination and alternatives but I would certainly look at enroute airport actuals and Tafs.

I mentioned flying from the mid UK to Aberdeen when there was extensive fog forecast.

I checked literally all the actuals and TAFS enroute for every airport. The whole lot looked awful.

My destination was clear and forecast to stay so although further south (Glasgow Edinburgh etc were all down at 200 metres)
Ireland was totally clear and forecast to be totally clear so I opted to go with loads of fuel and in a capable twin.

Had I been in a single NO WAY!!!

Because you cannot see it doesnt mean its not there and cannot bite you! bit like at night really when you fly into a CB because you cant see it.

That is the time to be more on alert at what lies below the cloud as you will still find the fog when you dont want to :E

If you close your eyes to that then your playing russian roulette! I too dont trust pistons.

Most of us have played russian roulette at some time or other me included (more than I would admit to) but at least be aware that you are playing Russian roulette and dont try and justify it as a safe way of operating because its not ?

Pace

Big Pistons Forever
4th Aug 2011, 00:01
As I have posted elsewhere around 80% of all engine failures are directly caused by the actions or inactions of the pilot. Running out of/mismanaging fuel and carb ice are the leading cause of engine failures, both totally preventable by the pilot.

I have done some single engine for real IFR and I want to see 500 feet AGL and 1 mile vis in flat country. For over mountain IMC the cloud base needs to be 500 feet higher than the highest ground with 2 mile vis. I feel the probability is high enough that I could make a survivable landing even breaking out at only 500 feet, that the risk is acceptable.

Frankly of more concern with single engine IFR is you generally only have one vacuum pump and one alternator and generally no de-icing and weather avoidance tools. Those limitations IMO represent more of problem than the one engine.

This reminds me of a conversation at the flying club one rainy nasty day. One guy had just made the statement that he would never fly IFR in a single, when a very experienced retired ATPL walked in. The fellow than said

"Bob how many hours of single engine IMC time do you have?"

After pondering the question for a minute he replied

" I guess about 10 hours"

Another fellow then piped up

" No, he means single engine IFR in an airplane that only had one engine !:uhoh:"

The reply from Bob was instant

" Oh I have never flown IFR in a single"

:)





2)

IO540
4th Aug 2011, 07:05
Pace

One "problem" in these threads is that actually "we" do things a lot smarter than we spend time writing about. So to a casual reader some little snippet might sound a bit dumb.

Sure one looks at the bigger wx picture. I doubt I would overfly 200nm of solid fog. But such conditions would probably occur in the context of some bigger crap, enroute and/or in the terminal areas. Vast tracks of fog might be flying parallel to a warm front (you can tell I've been swatting the JAA IR Met can't you ;) - getting 85% now ;) ) but I am not going to be doing that in the first place because most of my long flights are discretionary, not human organ deliveries, and there is no point in flying somewhere if the arrival is OVC003 and it's raining so all you can do there is sit in a cafe :)

We all play Russian Roulette in terminal areas at many airports. The only debate is what % of your life you spend inside those brief time windows. I've never been concerned overflying the Alps but on a recent flight over the Pyrenees (http://s101.photobucket.com/albums/m74/peterh337/?action=view&current=Untitled-5.jpg) there really were few if any opportunities for a good half an hour. One crosses one's fingers and takes a lot of photos, but I wouldn't do it daily.

Regarding the issue with examiners' preferences, they fly daily and have to do it in both FTO hardware (some of which will be privately owned and leased to the FTO, and in my experience from various training most of the planes are maintained to a pretty minimal level) and privately owned hardware (which ranges from carefully maintained, to absolute junk). I can understand they don't want to take risks because they do this all the time. On the occassions I have done some mentoring, it was always in my own plane. If I go to Greece to do my IR (my 1st and 2nd choice are both UK, currently) it will be in a DA42 not in a DA40 ;)

Big Pistons Forever

Frankly of more concern with single engine IFR is you generally only have one vacuum pump and one alternator and generally no de-icing and weather avoidance tools. Those limitations IMO represent more of problem than the one engine.I agree but that's a separate argument, because there are singles which are dual redundant e.g. the Cessna 400. 2 alternators, 2 batteries, two main buses with various cross-switches... like a 737 really :)

Also a lot of things can be backed up. To cover for alternator failure, you have

- a battery of known good condition (not a 5 year old Gill)
- a handheld radio, connectable to a rooftop antenna via a cable
- a handheld GPS (or two)
- a headset adapter for the handheld radio

The above stuff costs peanuts. To cover for a vac pump failure, you have

- an electric horizon
- possibly a backup (electric) vac pump, though those are pretty heavy, and actually the vac horizon is almost as likely to go, IME
- partial panel currency

Avoidance of ice and wx is best done by not flying in thick IMC enroute for hours. This is more complex. On a G-reg, for cert for flight in icing conditions, the UK CAA is happy with one alternator. The FAA requires two. It's debatable, because a lot of people fly non-deiced planes in icing conditions, with a way out (usually a descent into warmer air, sometimes a climb up into sunshine though that usually needs an IR and if you have that then you will have planned to be higher anyway, unless flying "VFR" to avoid the 2000kg+ route charges, or trying to avoid using oxygen and that is a really dumb way to fly because it traps you in IMC on most airways flights). You have to be smart about it no matter what, because having rubber boots is no assurance against ice if you are spending hours in IMC below zero. It merely gives you more options. Ice will still accumulate on unprotected surfaces and there are loads of those. I have a de-iced TKS prop but have only one TKS pump. On a full TKS system you have two pumps but the prop TKS is still a single point of failure and if your prop ices up badly then you are going one way anyway...

Oh I have never flown IFR in a singleThat is a common attitude among airline pilots; fair enough. I also know some who think a SE should not venture outside the circuit :)

what next
4th Aug 2011, 08:20
Good morning!

We all play Russian Roulette in terminal areas at many airports.

Why would "we all" do that? The majority of airports I fly to and have flown to offer enough chances for a forced landing (with a single, not with a triple seven of course!) under their approach and departure routes. And the ones that don't, I won't fly to in a single. (ex) Berlin Tempelhof comes to mind, where several fatal accidents with SEPs have occurred over the years following engine failures during approach or departure. In a twin or bizjet on the other hand, Tempelhof was one of the finest destinations in Europe!

Regarding the issue with examiners' preferences, they fly daily and have to do it in both FTO hardware...

And I would say, the same applies to instructors and all other (semi) professional aviators as well. And I would also say, that this applies to every self-flying businessman when he is not the sole occupant of his aircraft. Employees can't usually say "no" when their boss takes them on a business trip in his aircraft, but they have the right to be protected from being part of the russian roulette game of their "owner"!

The above stuff costs peanuts. To cover for a vac pump failure, you have...

In the year 2011, all you really need is the latest generation iPhone or iPad. For 400 currency units, it gives you sufficient attitude information (via solid state gyros), navigation (GPS based, with free VFR and IFR enrout charts and even with approach plates if you pay for them) and communication (from the altitude at which singles mostly operate, you can call almost every air traffic controller by phone, just make sure that you have the relevant numbers stored in your phone). And the battery lasts longer than the fuel in your tank.

IO540
4th Aug 2011, 09:24
I will leave the Russian Roulette debate now as it has been done to death, other than to say that based on your principles there would be no SE flight, other than a few trivial routes.

In the year 2011, all you really need is the latest generation iPhone or iPad. For 400 currency units, it gives you sufficient attitude information (via solid state gyros),

I don't think these are self erecting i.e. if you fly in a 30 degree coordinated turn for a bit, the "gyro" will indicate a level roll attitude.

That is the fundamental issue which all solid state gyros have; one has to introduce GPS or airdata, to "fix them up" when straight and level flight is indicated externally.

What app do you use? We have both types of Church of Jobs media players / pigeon english messengers (an Iphone4 and an Ipad2) kicking around the house.

The Garmin 496 "instrument panel" with its fake gyros actually works properly and does so in a long term sense - so long as you avoid getting into a serious unusual attitude. It works by crunching the GPS trajectory data.

you can call almost every air traffic controller by phone, just make sure that you have the relevant numbers stored in your phone).

Here in the UK, there is rarely any GSM connectivity above 1000-2000ft. I do have a satellite phone though :) They are £300 on Ebay now... but the controllers are not on the phone (on public numbers). Only their assistants are. It ought to work in an emergency, but a handheld radio is a whole lot easier. There is no way to hear a mobile phone in a typical piston cockpit. I guess one could construct a headset adapter for an Iphone, or use a bluetooth connection with the Bose A20 or Zulu headsets.

And the battery lasts longer than the fuel in your tank.

Not in my TB20, if the Ipad is on max brightness, which it needs to be to be anywhere near bright daylight readable. About 5hrs. I am getting a power unit sorted though.

Pace
4th Aug 2011, 10:32
I will leave the Russian Roulette debate now as it has been done to death, other than to say that based on your principles there would be no SE flight, other than a few trivial routes.

10540

Its not so much a question of SE but different horses for different courses.
You would no sooner take off into known icing conditions in a PA28 than I hope you would not takeoff in a PA28 to fly over 200 nm of fog.
Pilots do these things! Pilots Ferry singles across the north Atlantic summer and winter! Knowing the sea I would not be comfortable doing that although I do ferry multi engine.

I know of a colleague who is a jet jockey like myself who came up through ferrying. He ran out of fuel ferrying over the north Atlantic (ferry tank transfer problem) Glided IMC breaking out at 500 feet above the only fishing boat in the north Atlantic.

He had to spend a week on board before the fishing boat returned to the mainland. What a lucky guy.

So all I am saying is that a single engine club aircraft is not designed for all weather flying. There are pilots who will use them for all weather flying and night flying but they are increasing their RISK dramatically by using aircraft that are not up to the job.

I have had 3 engine failures not caused by mismanagement. 2 were partial 1 was full so I am sorry but I do not have the confidence that some hold on Piston engines and would be wary of taking my aircraft and PAX into a situation where there are "no outs" if the only door closes on me.

Pace

what next
4th Aug 2011, 10:36
...based on your principles there would be no SE flight, other than a few trivial routes.

That's really not true! Coming back to the original question, observing a reasonable minimum ceiling you can take the factor "luck" almost completely out of the equation. Where I fly SE IFR, this value is 1000ft, and it is not flat, uninhabited terrain, but there are mountainous regions like the Black Forest and also some larger cities and towns instead!

I don't think these are self erecting i.e. if you fly in a 30 degree coordinated turn for a bit, the "gyro" will indicate a level roll attitude.

Yes, of course. But that is not what you will do in a limited-panel emergency situation. All you need is to keep you wings level and work with small changes in pitch and direction from there on. Just like you would when flying with turn-coordinator, magnetic compass and altimeter.

What app do you use?

Myself none, because I don't have an iPhone or iPad (although I've been a Macintosh user for over 20 years). But all our students and co-pilots play with these things all the time, so I feel very safe in the event of an instrument failure :O

Here in the UK, there is rarely any GSM connectivity above 1000-2000ft.

Really? During single-engine flying (rarely above FL80 in my case), I usually leave the mobile phones on and have a connetion most of the time.

It ought to work in an emergency, but a handheld radio is a whole lot easier.

Sure. But every pilot has a mobile phone and very few have a handheld radio. And even those with a radio - when did they last charge their battery?

...but the controllers are not on the phone (on public numbers).

Many tower controllers are, especially at smaller (but controlled) airports! We need to call them all the time to co-ordinate our training approaches. And if you have the first one on the phone, he will be able to either connect you to the next one or at least to relay your message. Talking to ATC on the phone even briefly with a bad connection in case of communication failure will take most of the stress away from the emergency.

IO540
4th Aug 2011, 12:17
But every pilot has a mobile phone and very few have a handheld radio. And even those with a radio - when did they last charge their battery?

This kind of thing has to be done properly. With an Icom-type radio, you have the standard NIMH battery, which one needs to fully discharge and recharge say every 6 months (and which IME has substantial capacity left at that point), and you should also carry a second battery which is made from an Icom empty battery pack (very cheap, about £20 I think) packed with lithium cells which have a shelf life of about 20 years. Put a bit of insulating tape over the terminals so it doesn't get shorted in the "emergency bag" ;)

During single-engine flying (rarely above FL80 in my case), I usually leave the mobile phones on and have a connetion most of the time.

Not here.

An SMS occassionally gets through, even at much higher altitudes.

Fuji Abound
4th Aug 2011, 12:57
500 feet seems ok as you dont really want to pull the chute much lower. :ok:

Contacttower
4th Aug 2011, 15:55
I have on several occasions tried to get signal at FL90/100 over both the UK and France recently and although sometimes the phone will claim to have signal it won't actually send anything.

Big Pistons Forever
4th Aug 2011, 18:40
10540


So all I am saying is that a single engine club aircraft is not designed for all weather flying. There are pilots who will use them for all weather flying and night flying but they are increasing their RISK dramatically by using aircraft that are not up to the job.

Pace


Exactly. And IO540 I do not think you can extrapolate the capabilities of the Cessna 400/ Piper Malibu/FIKI turbo'd G3 Cirrus across the GA fleet as these very capable singles represent a small proportion of the fleet.

Your point about the capabilities of the latest generation of portable GPS "instrument panels" is very valid as now any aircraft can have a truely redundent blind flying panel which will keep you right side up when all else has failed.

In any case what I post seems to bother you as you seem incapable of agreeing with anything I post so I will refrain from derailing any more threads with any discussion on topics you seem very invested in.

Cheers

BPF

IO540
4th Aug 2011, 19:51
And IO540 I do not think you can extrapolate the capabilities of the Cessna 400/ Piper Malibu/FIKI turbo'd G3 Cirrus across the GA fleet as these very capable singles represent a small proportion of the fleet.

I don't recall ever suggesting that one could do the same thing with a PA28-140 as one can do with a Cessna 400. Did I ?

The vast majority of the "spamcan" fleet is unsuitable for high altitude ("Eurocontrol") IFR, except at the very bottom end e.g. FL100 on nice days. The maintenance practices are also often dodgy.

I fly a TB20, which has a deiced prop, a 20k ceiling, oxygen, etc, is maintained with money being no object, I do 100-150hrs/year in it, and my attitudes to risk are based on that.

In any case what I post seems to bother you as you seem incapable of agreeing with anything I post so I will refrain from derailing any more threads with any discussion on topics you seem very invested in.

I don't have any problem with what you write. You have one attitude to risk and I have another. No problem with that. We all make decisions according our attitudes to risk.

I am actually more cautious than most IFR pilots I know (for example I don't do any significant IMC enroute at "Eurocontrol" altitudes) and this is one reason I don't go on group flying trips because I would just get left behind at the first bit of frontal weather which the others are quite happy to drill through.

What I disagree with is if somebody has an illogical attitude e.g. won't fly above known fog but will fly above an overcast under which could be unknown patches of fog.

Pace
4th Aug 2011, 21:03
10540

What I disagree with is if somebody has an illogical attitude e.g. won't fly above known fog but will fly above an overcast under which could be unknown patches of fog.

I totally agree with you that we all have different attitudes to risk. Some pilots will do things that others would not contemplate.

If you want NO risk in aviation do not climb into an aircraft full stop! from that point on its about how much risk you are prepared to take and how to minimise those levels of risk.

I dont understand your analysis highlighted above?

If I was flying a single prop over an overcast or through frontal weather I would want to know whether I was likely to break cloud enroute in the vent of an engine failure.

If flying over mountains in a glide would I hit terrain still IMC?

Over low ground would I be able to make a visual landing?

I would look at the weather over my planned track. I would check temps and dewpoints but above all I would take all the airfields enroute and get actuals and Tafs.

If as you say I descended through an overcast to see patchy fog then I would land in an area that didnt hold a patch of fog as simple as that.

If I descended through an overcast and there was extensive fog then I am the fool as no one to blame but me :E

Or for night and fog SE I would buy a nice Cirrus and pull the shute :)
Never ever do anything in aviation without an out at least the Cirrus gives you an out :E
I have in the past taken huge risks flying so I am not talking from a holier than thou position but I do try to balance those risks by having a number of options.
On the occasions that I have done something with no options left then I must admit to feeling **** scared till its over and thanked whoever your God is for sparing me.

Pace

IO540
4th Aug 2011, 22:41
I don't disagree in principle, Pace, but I will accept short time windows where there is very low cloud (or fog) in the context of a long flight.

My reasoning for this is that it is not practical to avoid it comprehensively.

Let's say you are doing an 800nm flight. The only idea you have of surface conditions (in any reliable sense) are METARs obtained immediately before the flight. A few might feature fog or low vis etc but they are only reporting conditions within a very limited radius of the aerodrome, and your glide distance from say FL150 is going to be way longer than that.

You could get the UKMO visible image (http://www.metoffice.gov.uk/satpics/latest_VIS.html) which will show fog banks, but only if the conditions are otherwise blue-sky. And there is no way to use this to distinguish between solid fog and a layer 3000ft thick with a 1000ft base, because the tops temperatures will be very similar. Nevertheless I have used this image to see what a large chunk of coastal fog was doing, on an otherwise clear day.

Pace
4th Aug 2011, 22:57
I have left the UK in the past in CAVOK Got to the channel and crossed with extensive fog over the channel!

One occasion the fog was so thin there was almost a Salvidor Dali picture of ships funnels carving trails through the fog :E

I was in a twin.

Having said that in a single in that situation I would have had an out. Fog is likely to equal calm glass like sea.

Thin fog and maybe a radar altimeter set at 30 feet! Flair and chances are you may do a half reasonable landing on the sea surface ;)

Pace

IO540
5th Aug 2011, 06:47
I don't see a special hazard in ditching in fog, relative to ditching without fog, especially as (as you say) the sea state is likely to be calm.

A radalt? I know a few TB20 pilots who have put in a KRA10. I wonder what they use it for.

what next
5th Aug 2011, 08:03
A radalt? I know a few TB20 pilots who have put in a KRA10. I wonder what they use it for.

A radio altimeter is an excellent reminder that you have reached your minimum. Over the years, I had countless incidentens with students and infrequent IFR-flyers who were so busy keeping their ILS needles centered that they forgot to look at the altimeter. In the procedures trainer, I let them continue to touchdown without intervening. You should see their puzzled faces when they suddenly hear the "squeak" sound from the tires (or the "crash" sound if the sink rate is too high or they land beside the runway)! "Why was that?" is the usual answer...

Another use is as a primitive ground proximity warning system. Everybody has heard (or should have heard) about the calculation of "minimum usable flight levels" in non-ISA atmospheric conditions. But how many actually perform this calculation when they fly IFR over mountainous terrain in underpowered aircraft? A radio altimeter ca save your day then. Of course, modern GPS based avionics have a much better terrain warning built into them, but not every little club aircraft has them.

Pace
5th Aug 2011, 08:11
I don't see a special hazard in ditching in fog,

I do ;) No one would find you! maybe a long pole with a flag you could stick up through the fog and wave to passing ships before one ran over you :E

Serious though I had a nasty experience years ago with a jammed fuel selector and unforecast extensive fog.
Low on fuel I took to a military base who were colour code red and had a PAR, talked all the way down to an 80 foot cloud base and 400 vis:eek:
After that I tried to see whether it was possible to land in zero zero conditions using a radar alt for the flair.
Tried the experiment on an ILS in VMC with a safety pilot and yes I feel confident in an emergency its quite feasible using a rad alt in a Seneca Twin.

Pace

Local Variation
5th Aug 2011, 15:52
Has been debated at our Club on numerous occassions.

Based on cloud OVC, SEP IMCR PPL, we reakon 1800 feet over land. The situation is an emergency, which when in cloud could lead to distraction followed by loss of situational awareness and associated loss of control. Any passengers in the back are going to panic big time and will distract the PIC.

Coming out the bottom of the cloud without an engine / or fire without the view of a landing site is going to test the best. Worst case could see the a/c well out of straight and level.

We based 1800 feet on a real emergency event where the a/c was close to being inverted and needed all of that to recover.

It's all down to experience and is therefore subjective. My CFI told me that I would need 1800 minimum feet given my experience and as such if it OVC for the route, I want 2000 feet to play with (I'm hopeless at forced landings).

IO540
5th Aug 2011, 18:23
A radio altimeter is an excellent reminder that you have reached your minimum

Only at airports whose approach terrain has been suitably prepared for radalt-based approaches (Cat3 only I think).

Those approaches switch the lateral autopilot guidance to the radalt at about 150ft which is well before the start of the runway.

Another use is as a primitive ground proximity warning system.

Very primitive; the beam points only slightly forward, so it will warn only against gradually rising ground.

Look up that seminal Mt Erebus crash. They had a radalt. It gave them just a few secs' warning. They pulled up to max, but too late. The only GPWS which actually works is a GPS plus a terrain map; mandatory in all transport planes over X seats.

Of course, modern GPS based avionics have a much better terrain warning built into them, but not every little club aircraft has them.

Yes; a £1000 Garmin 496, with its audio output wired to the intercom, is a vastly better "GPWS" than a £10000 KRA10 installation.

After that I tried to see whether it was possible to land in zero zero conditions using a radar alt for the flair.
Tried the experiment on an ILS in VMC with a safety pilot and yes I feel confident in an emergency its quite feasible using a rad alt in a Seneca Twin.

A reasonable autopilot will do that for you too, on an ILS. It will take you to the runway, and you will definitely have enough surface visibility at that point no matter how thick the fog is.

Based on cloud OVC, SEP IMCR PPL, we reakon 1800 feet over land

That seems OTT, because you could fly below the cloud, VFR, well above the MSA :)

Local Variation
6th Aug 2011, 08:59
I should enhance the qualification of that.

1800 feet was based on flight in the cloud (not on top nor below) with the sky overcast.

The VFR flight under MSA would obviously work, but the original question was, I assumed, regarding flight out of sight of the surface, eg IMC in an SEP.

Pace
6th Aug 2011, 19:59
A reasonable autopilot will do that for you too, on an ILS. It will take you to the runway, and you will definitely have enough surface visibility at that point no matter how thick the fog is

10540

Many wont! S Tech fitted to later Seneca Fives are rubbish King units fitted to earlier aircraft much better.
The S tech is fine further out on the localiser and glide but starts hunting the narrower the beam becomes.
In dense fog even coupled to the ILS how are you going to find a flair point without something like a radar alt?
The Radar Alt is a good bit of kit at low cost.

Pace

IO540
6th Aug 2011, 20:12
STec are made by Stec (now owned by Cobham), not King. Stec autopilots have rubbish performance (they are driven from the TC, not the AI, so they have no decent pitch/roll input) but they rule the retrofit roost because King (Honeywell) washed their hands of GA avionics 10 years ago (having overpriced them for years, with e.g. my KFC225 costing about $40k) and Stec ended up generating a load of STCs which made them easy to install.

However if your Stec autopilot is not capable of flying an ILS all the way down to the height specified in the POH, without oscillation, then it is a duff unit, a bodged installation, the unit has the wrong loop gain (etc) set up, or the STC it was installed under is duff (there are a few duff STCs around).