Choice of alternates
Thread Starter
Join Date: Dec 2011
Posts: 2,460
Likes: 0
Received 0 Likes
on
0 Posts
Choice of alternates
How many people would pick an alternate which is near the destination, and how many would pick one which is a long way away?
Let's say you are doing a training flight from Shoreham to Bournemouth, some approaches at Bournemouth, and then flying back to Shoreham.
How many would pick Southampton as alternate (given it has the same wx as Bournemouth and has the same sort of ILS) rather than pick e.g. Lydd or Southend (which are likely to have different wx)?
The advantage of Southampton is that you can get a single train back to Shoreham, which you cannot do from any of the other places that have an ILS.
I tend to think of this as having a "crash alternate" (where a crash has closed the runway) and for that a nearby airport is fine, and a "weather alternate" (which obviously needs to be more distant).
Let's say you are doing a training flight from Shoreham to Bournemouth, some approaches at Bournemouth, and then flying back to Shoreham.
How many would pick Southampton as alternate (given it has the same wx as Bournemouth and has the same sort of ILS) rather than pick e.g. Lydd or Southend (which are likely to have different wx)?
The advantage of Southampton is that you can get a single train back to Shoreham, which you cannot do from any of the other places that have an ILS.
I tend to think of this as having a "crash alternate" (where a crash has closed the runway) and for that a nearby airport is fine, and a "weather alternate" (which obviously needs to be more distant).
Join Date: Jan 1999
Location: north of barlu
Posts: 6,207
Likes: 0
Received 0 Likes
on
0 Posts
A huge amount of variable factors with this question and lots of scope for personal opinion.
If this is about getting things right for the 170A then as long as all the usual criteria are met (WX, approach aids, airfield open, big enough runway etc) then all else is just personal opinion.
If this is about getting things right for the 170A then as long as all the usual criteria are met (WX, approach aids, airfield open, big enough runway etc) then all else is just personal opinion.
Join Date: Dec 2005
Location: LKBU
Posts: 435
Likes: 0
Received 0 Likes
on
0 Posts
Unless there is a risk of weather deteriorating below CAT I (or whatever the aircraft and the pilot are certified for), I would pick an alternate as close as possible, but with:
- Better navaids and approach facilities
- Longer, hard runway
- Several runways in different directions, or at least a better orientation of the only runway with respect to prevailing winds
- Flatter terrain and fewer obstacles around
- Familiar to me
Join Date: Feb 2007
Location: Amsterdam
Posts: 4,598
Likes: 0
Received 0 Likes
on
0 Posts
Also be advised that *some* airfields require PPR or PNR if you nominate them as your alternate.
(In real life, if you really need that alternate and forgot PPR or PNR, then you'd probably land anyway and sort out the mess on the ground. But it might be an "issue" on your exam.)
(In real life, if you really need that alternate and forgot PPR or PNR, then you'd probably land anyway and sort out the mess on the ground. But it might be an "issue" on your exam.)
Join Date: Sep 2003
Location: UK,Twighlight Zone
Posts: 0
Likes: 0
Received 0 Likes
on
0 Posts
Poor old Peter. Every time he starts a new thread it is assumed to be another 170a failure point...
Join Date: Apr 2011
Location: Leeds, UK
Posts: 75
Likes: 0
Received 0 Likes
on
0 Posts
My alternate (for returning home) is the closest aerodrome / airport with published approaches. Worst case there is I fly down to minima, have a cuppa tea and either go home via bus or fly back later in the afternoon.
When going elsewhere, I usually go for 2 alternates: 1 local with published approaches (if my destination doesn't have approaches) and a second, a good distance away where hopefully the weather would be somewhat different.
When going elsewhere, I usually go for 2 alternates: 1 local with published approaches (if my destination doesn't have approaches) and a second, a good distance away where hopefully the weather would be somewhat different.
Join Date: May 2001
Location: 75N 16E
Age: 54
Posts: 4,729
Likes: 0
Received 0 Likes
on
0 Posts
If you are flying from EGKA to EGHS is there anything wrong in nominating the departure airfield as the alternate? So if Bournemouth is closed due to weather or a blocked runway, you just turn around, and fly the 30 minutes home where you know the weather will be ok to land? That is what I'd do anyway.
In a TB20 full of fuel you could divert to any airfield in England so you could put down Newcastle as your alternate if you wanted, or pick one on the fly if alternate 1 is closed,
The 170A is a load of utter bollox in my humble opinion, and I have never come across anywhere where you have to pass a test to be allowed to do a test!
In a TB20 full of fuel you could divert to any airfield in England so you could put down Newcastle as your alternate if you wanted, or pick one on the fly if alternate 1 is closed,
The 170A is a load of utter bollox in my humble opinion, and I have never come across anywhere where you have to pass a test to be allowed to do a test!
Join Date: Oct 2011
Location: UK
Age: 40
Posts: 211
Likes: 0
Received 0 Likes
on
0 Posts
Diversion aerodromes is a personal preference. Here are my considerations...
I'll always have one alternate that's near to my destination which you might call a 'crash div' or whatever. It's purpose is to be there if some unlucky sod ploughs the runway at the destination and it can't be hoovered up before the fuel endurance approaches. Let's be honest if it'll only take 15-20 mins to clear up whatever is obstructing the runway, I'd rather do a few orbits/GH and get in to where I'm supposed to be going than divert elsewhere. This div is plogged properly.
I'll always have an en route diversion too. Simply just in case something goes wrong at altitude and I know where I'm going to try to land. I wouldn't book it as a diversion, it'd be a bloody emergency - I'm landing! Likewise I wouldn't have this one plogged either, just a knowledge of where it/they is/are from my track.
A weather diversion always seems to me to be too cowboy like. The short trips that most PPLs do arn't long enough for the weather to become 'unexpected'. I concede that on longer international and transcontinental flights, how much you trust the weather man is down to your judgement alone. I'd have a good planned weather div for these types of flight. But as before, for a PPL in the UK if the weather is pants, turn back and return to whence you came! Or back to where you didn't continue into the poor weather in the first place. This is very IFR capability determined.
In selecting a div I look for general weather (VFR if possible) and more importantly the wind direction and strength. I wouldn't be comfortable having a planned alternate where the wind strength would be at the 'demonstrated crosswind limit', sods law says it'll be outside of the limit and I'd break something. At the same time as reasoning with the weather I consider runway length, but only in so much as, is it long enough. And I mean long enough, no adding extra length for whatever silly reason. We learn PFLs, flapless, glides, and short field techniques for a reason, and any strip with an ATZ is likely to have at least 600m grass (which is fine for most if not all singles, and many twins in most weather conditions that GA tend to fly in).
After the weather and wind, I don't really care what facilities are available! Yes a cuppa and some avgas might be nice, but then most airfields that make sensible diversions have these facilities anyway. In my mind, a diversion is an emergency situation for whatever the reason, be it you, or someone else at your original destination. Of course if a narky hass-hole says you cannot divert because you've not booked an aerodrome "Pan-Pan short of fuel" would probably work just nicely!
I'll always have one alternate that's near to my destination which you might call a 'crash div' or whatever. It's purpose is to be there if some unlucky sod ploughs the runway at the destination and it can't be hoovered up before the fuel endurance approaches. Let's be honest if it'll only take 15-20 mins to clear up whatever is obstructing the runway, I'd rather do a few orbits/GH and get in to where I'm supposed to be going than divert elsewhere. This div is plogged properly.
I'll always have an en route diversion too. Simply just in case something goes wrong at altitude and I know where I'm going to try to land. I wouldn't book it as a diversion, it'd be a bloody emergency - I'm landing! Likewise I wouldn't have this one plogged either, just a knowledge of where it/they is/are from my track.
A weather diversion always seems to me to be too cowboy like. The short trips that most PPLs do arn't long enough for the weather to become 'unexpected'. I concede that on longer international and transcontinental flights, how much you trust the weather man is down to your judgement alone. I'd have a good planned weather div for these types of flight. But as before, for a PPL in the UK if the weather is pants, turn back and return to whence you came! Or back to where you didn't continue into the poor weather in the first place. This is very IFR capability determined.
In selecting a div I look for general weather (VFR if possible) and more importantly the wind direction and strength. I wouldn't be comfortable having a planned alternate where the wind strength would be at the 'demonstrated crosswind limit', sods law says it'll be outside of the limit and I'd break something. At the same time as reasoning with the weather I consider runway length, but only in so much as, is it long enough. And I mean long enough, no adding extra length for whatever silly reason. We learn PFLs, flapless, glides, and short field techniques for a reason, and any strip with an ATZ is likely to have at least 600m grass (which is fine for most if not all singles, and many twins in most weather conditions that GA tend to fly in).
After the weather and wind, I don't really care what facilities are available! Yes a cuppa and some avgas might be nice, but then most airfields that make sensible diversions have these facilities anyway. In my mind, a diversion is an emergency situation for whatever the reason, be it you, or someone else at your original destination. Of course if a narky hass-hole says you cannot divert because you've not booked an aerodrome "Pan-Pan short of fuel" would probably work just nicely!
Last edited by GeeWhizz; 21st Dec 2011 at 13:55.
Join Date: Aug 2003
Location: Surrey
Posts: 1,217
Likes: 0
Received 0 Likes
on
0 Posts
geewiz,
so far I have had to divert 5 times (3 'crash' 2 weather)
2 x for collapsed landing gear, in each case it took way longer than 15 minutes to cleanup. Once I was in the crew room of the diversion for about 5 hours and once I did my whole BFR and then dropped the examiner at a different airport while they departure airport remained stubbornly closed.
In general in a spam can I wouldn't particularly plan a crash diversion unless I was in a particularly sparse airport area, the circumstances will always be different and my aircraft can get into most airports. If I was flying a G6 on the other hand.... (just wishing). On weather, I would plan something either local with an ILS if going into a VFR field or something in a different weather system (having made he mistake of not doing that, going missed at primary, then at alternate, and then needing to formulate a further alternative plan - fortunately with 600nm of remaining range)
so far I have had to divert 5 times (3 'crash' 2 weather)
2 x for collapsed landing gear, in each case it took way longer than 15 minutes to cleanup. Once I was in the crew room of the diversion for about 5 hours and once I did my whole BFR and then dropped the examiner at a different airport while they departure airport remained stubbornly closed.
In general in a spam can I wouldn't particularly plan a crash diversion unless I was in a particularly sparse airport area, the circumstances will always be different and my aircraft can get into most airports. If I was flying a G6 on the other hand.... (just wishing). On weather, I would plan something either local with an ILS if going into a VFR field or something in a different weather system (having made he mistake of not doing that, going missed at primary, then at alternate, and then needing to formulate a further alternative plan - fortunately with 600nm of remaining range)
Join Date: Oct 2011
Location: UK
Age: 40
Posts: 211
Likes: 0
Received 0 Likes
on
0 Posts
5 times?! You're a pro
The term 'crash' diversion is misleading. It could be for anything e.g. someone lost a panel and the runway has to be checked so it doesn't become a hazard for others. That wont take too long. Nose legs collapsing etc will obviously take a lot more time, but in either case the 'crash' div should be sufficient.
The term 'crash' diversion is misleading. It could be for anything e.g. someone lost a panel and the runway has to be checked so it doesn't become a hazard for others. That wont take too long. Nose legs collapsing etc will obviously take a lot more time, but in either case the 'crash' div should be sufficient.
Join Date: Aug 2003
Location: Surrey
Posts: 1,217
Likes: 0
Received 0 Likes
on
0 Posts
Thoughts:
Exam: anywhere suitable, and make the numbers work.
Real world cross-country in GA - I'm far more likely to divert due to weather or serviceability than I am due to a problem at my destination. So, I actually will have a series planned along my route - which really only means making sure I have visual and instrument approach plates readily to hand for my selection of choices. The diversion itself I just fly like an exam exercise - just route from a convenient waypoint along my existing route.
And just like the emergency exit, always remember that the best alternate may well be behind you!
Real world jet operations - pick the nearest legally feasible alternate to the destination, that way your landing fuel can be minimised, and so payload maximised and costs minimised.
G
Exam: anywhere suitable, and make the numbers work.
Real world cross-country in GA - I'm far more likely to divert due to weather or serviceability than I am due to a problem at my destination. So, I actually will have a series planned along my route - which really only means making sure I have visual and instrument approach plates readily to hand for my selection of choices. The diversion itself I just fly like an exam exercise - just route from a convenient waypoint along my existing route.
And just like the emergency exit, always remember that the best alternate may well be behind you!
Real world jet operations - pick the nearest legally feasible alternate to the destination, that way your landing fuel can be minimised, and so payload maximised and costs minimised.
G
G
Thread Starter
Join Date: Dec 2011
Posts: 2,460
Likes: 0
Received 0 Likes
on
0 Posts
Exam: anywhere suitable, and make the numbers work.
But Backpacker's 1st post in this thread is indeed near the mark as regards what prompted the question
The "nice chap" (who I shall not have the pleasure of flying with again, ever) insisted that Lydd or Southend are not acceptable alternates and that Southampton is the correct one.I don't have problem with picking alternates for all my "real" flights. With a ~1300nm zero-fuel range I normally pick a selection of airports which have the approach aids (ILS being the one of choice by far), avgas, Customs, and which one would not mind being stuck in for a day or two. In most places in Europe (north of say Italy or Greece) this is a non-challenge. I use a satellite phone to check the tafs and metars at all the airports in question, way before I get there.
PPR/PNR is not a huge issue (IMHO) because while yes you should get PPR/PNR the reality is that once you are on your way to the alternate the situation is a full emergency and you will just declare a mayday (if necessary, in southern Europe, citing "low oil pressure") and land there regardless of any landing clearance. The only time I would obey a refusal to land (which itself would be hugely unprofessional of ATC) would be if I had other good options or if I was going to be fired at.
Obviously it would be stupid to file Gatwick or Heathrow as alternates (because there are other options nearby such as Southend which is H24 with an ILS... except the ILS is INOP right now
and doesn't cost £500 plus an absolute arm and a leg in parking costs) but in the more common context one might be talking of an airfield which is PNR/Customs but is otherwise open to GA and not busy.I just wondered why the hell somebody would pick Southampton as the alternate in the scenario originally described. I was hoping somebody could illuminate that choice. To me it makes sense only if Bournemouth was closed due to a crash or some runway contamination etc, or the ILS became INOP and it was ~OVC004 and you wanted to be able to get home using a single train journey. Lydd and Southend are in the sticks but in nearly all cases of a wx diversion one can fly home the next morning in good VFR conditions
Last edited by peterh337; 21st Dec 2011 at 17:40.
Join Date: Jan 2002
Location: Aberdeen
Posts: 1,234
Likes: 0
Received 0 Likes
on
0 Posts
My approach (from a VFR only perspective) is closer to Peter's. To be any use, a realn alternative has to have differing weather. So major topographic features, sea, stuff like that make airfields worthy alternatives.
So called 'crash' alternatives - I've had to use them 3 or 4 times and at those times the 'nearest' button on the GPS, alllied to a flight guide are fine - the weather is still flyable, loads of fuel all sorts of things are possible.
Crossing the Channel on a poor VFR day - often the only viable alternative will be on the side you started from. Typically the majority of diversions I have made have come from reaching a point where I was not longer happy VFR and usually turning through an angle much greater than 90 degrees. Might waste some time but there is nothing much more comforting than retracing your path through a 'known' environment.
So called 'crash' alternatives - I've had to use them 3 or 4 times and at those times the 'nearest' button on the GPS, alllied to a flight guide are fine - the weather is still flyable, loads of fuel all sorts of things are possible.
Crossing the Channel on a poor VFR day - often the only viable alternative will be on the side you started from. Typically the majority of diversions I have made have come from reaching a point where I was not longer happy VFR and usually turning through an angle much greater than 90 degrees. Might waste some time but there is nothing much more comforting than retracing your path through a 'known' environment.
Join Date: May 2001
Location: 75N 16E
Age: 54
Posts: 4,729
Likes: 0
Received 0 Likes
on
0 Posts
The problems with Exams is that they are not real world scenarios. If you were going to EGHH because you NEEDED to go, then maybe Southampton might be a fine alternate. If you are going for training, then I'd just go home.
What are the rules with regards to Alternates? If the destination is forecast to be VFR then you don't even need to file an alternate right?
As a general rule, I'd file an alternate which has a different climate, so SOU and Bournemouth are not good, because if the weather is crappy at EGHH then it is likely to be crappy at Southampton too. You'd be better off filing Boscombe Down as it is inland, or I agree with you Lydd or Southend as they are likely to be in a different air mass if there is frontal stuff coming in from the SW (plus you have the chance to check Shoreham on the way past and dive in there and just go home for a beer if weather permits).
What are the rules with regards to Alternates? If the destination is forecast to be VFR then you don't even need to file an alternate right?
As a general rule, I'd file an alternate which has a different climate, so SOU and Bournemouth are not good, because if the weather is crappy at EGHH then it is likely to be crappy at Southampton too. You'd be better off filing Boscombe Down as it is inland, or I agree with you Lydd or Southend as they are likely to be in a different air mass if there is frontal stuff coming in from the SW (plus you have the chance to check Shoreham on the way past and dive in there and just go home for a beer if weather permits).
Join Date: Dec 2005
Location: UK
Posts: 1,164
Likes: 0
Received 0 Likes
on
0 Posts
Maybe im stating the obvious here but if this is in reference to an IR skills test then the flight should be treated as a public transport flight(certainly used to be when I did mine, albeit some time ago now). If its still the case then I would be applying the relevant EU Ops criteria to select an appropriate alternate(if required....or even 2 alternates if legally required). Thats perhaps what your examiner was looking to see in your planning and may explain why he said your choice of alternate was wrong.