Flight Planning for an IMC Flight

[PUFL]

I have been told that flight planning for vfr and ifr are the same, instead of aiming for visual turning points, you plan to route over beacons...

Is this broadly correct or should I aim for an off-set of a beacon to avoid dangers of collision over a beacon, etc.

We can assume there is no radar service watching over me. Also, experience/goal is IMC level rather than IR.

Thanks.

[Johnm]

In the open FIR you can route where you like, but if flying IFR above the transition altitude you must fly quadrantal levels.

[IO540]

It depends on where you are coming from. Have you got a PPL and the IMC Rating, or just a PPL?

In Class G you can fly anywhere. The route chosen depends on your navigation method; normally one would choose to route via VORs because VOR/DME makes a good backup for a GPS, but often there is no VOR (or NDB) there so one can pick up airways intersections (they are also in the GPS database so they are handy). One should never use user waypoints in a GPS, due to the potential for data entry errors.

[PUFL]

Say you are routing Elstree to Bembridge (assuming it's back in action!), via somewhere near Booker to make the turn south but in any case avoiding LHR class A. All in IMC but out of airways and no GPS just standard VOR/NDB/DME.

[Johnm]

Say you are routing Elstree to Bembridge (assuming it's back in action!), via somewhere near Booker to make the turn south but in any case avoiding LHR class A. All in IMC but out of airways and no GPS just standard VOR/NDB/DME.

Don't even think of it without GPS and radar cover. In theory you could fly VOR radials off CPT and SAM but I woudn't recommend it unless you were desperate.

[IO540]

Say you are routing Elstree to Bembridge (assuming it's back in action!), via somewhere near Booker to make the turn south but in any case avoiding LHR class A. All in IMC but out of airways and no GPS just standard VOR/NDB/DME.

In Class G, you can fly anywhere. Just get the map out and draw a route

By all means get a radar service but there will be hardly any GA traffic on an IMC day anyway...

[Miroku]

one can pick up airways intersections (they are also in the GPS database so they are handy).

I0540, would you mind expanding on this please? I've not heard of this before. I'm assuming this would work on my Airbox Clarity?

[Fuji Abound]

Don't even think of it without GPS and radar cover.

Radar cover is almost an irrevelance - you will see little traffic about on this route on a genuinely IMC day and in any event the chance of hitting someone is way less than the risk of an engine failure. Of course it just might happen. For that reason I personally prefer to use some form of TAS or to be in receipt of a service but many quite reasonably dont. In reality you will get a service most of the way. Farnborough North and West will take you just about from west of Heathrow all the way down to the edge of the downs - thereafter you might persuade Solent to give you a service if you ask nicely, but dont count on it because it is outside their remitt. You could route through Luton and SVFR through Heathrow if the base is high enough.

GPS is nto a bad idea if you doubt your ability to navigate. The airspace along this route is quite tight in terms of avoiding the various bits of class D and class A. You will not be kindly received if you infringe. On the other hand with radar cover you will get some warning although obviously that is not something on which to rely.

If you are itending to stop at Bembridge assuming it is open and then return to Elestree the cloud base will obviously be very relevant because neither have an useful let down. It is relatively safe to make a cloud break at Bembridge from the east (over the sea). If push comes to shove you can probably negotiate a let down at Southampton or for sure at Shoreham if for example it is a matter of getting visual below a base of 800 feet or above. Neither are good locations for a made up let down at or in the vicinity of the overhead with high ground and masts around. Nor are you likely to get an accurate indication of the base. I would leave that for those folk who "know" what they are doing.

If you go anywhere near Parham do take account that they often have gliders up with surprisingly low bases.

one can pick up airways intersections

I think he means most GPS setups will have the airways intersections in their database effectively like another set of VRPs although hopefully more certain that they have been accurately included! Obviously with a GPS you can use these for a steer and the controllers will be familiar with them so if push comes to shove you can either ask them for a heading or indicate that a particular intersection is your next RP.

[Duchess_Driver]

Don't even think of it without GPS and radar cover. In theory you could fly VOR radials off CPT and SAM but I woudn't recommend it unless you were desperate.

Okay - so we can forget about the VOR/DME at BNN, the NDB's at HENton, BURnham, WestCOtt and WODley.

We can also forget about the traffic or deconfliction service provided by either Farnborough Radar on 132.8, 125.25, Benson on 120.9 or Luton 129.55 if they're not busy.

If you want to just stare head down at the GPS unit - pray that we've got a signal and that the database it is loaded with is upto date.

Use ALL methods / facilities available to keep your spacial awareness and your options open in the event of system failures.

DD

[IO540]

When I plan a "UK-style VFR" flight (i.e. one where you may encounter IMC and, being instrument qualified and capable, you proceed in IMC) I plan it on VORs as far as possible.

If there are no VORs handy, NDBs will do, otherwise I use airways intersections e.g. ORTAC, ROLEX, etc.

The airways intersections come in handy when crossing to another country too because you pick ones which lie on the FIR boundary (e.g. SITET) and then your plog will have the ETA to SITET which you stick on the flight plan.

The catch is that intersections are obviously RNAV-only i.e. GPS and no backup exists. I am not concerned about that myself because there are usually other ways in such a case.

It is no rocket science to do this, and one should not read more into it.

[SNS3Guppy]

Don't even think of it without GPS and radar cover.

Wow. How does one imagine we manage to navigate without GPS?

One should be able to do so quite well, else one ought not be navigating.

Is this broadly correct or should I aim for an off-set of a beacon to avoid dangers of collision over a beacon, etc.

Generally one should plan to a waypoint, rather than offsetting to one side or the other.

When planning RNAV or GPS waypoints, one differentiates between "flyover" and "fly past" waypoints, but in planning a flight under VFR or IFR, one generally lays out the waypoints that define the route. If you pick DOV VOR, for example, you're naming that as a waypoint on the route, and your flight is planned to fly to that VOR, then on to another waypoint. A waypoint can be an intersection, a point along an airway arranged by name, distance/radial, or any other means, but one defines the route by waypoints. Waypoints can be airports, NDB's, VOR's, or simply RNAV/GPS intersections (if that's the form of navigation you'll be using). Your flight plan presumes to fly directly to each of these waypoints, one after the other, thus laying out the course you intend to take.

In practice, when actually flying a route, it's common to offset to the right by a little bit. Today with GPS navigation as accurate as it often is, aircraft can find themselves within a few meters or less of an airway centerline most of the time. This puts all the aircraft on the same airway in the same place, which isn't necessarily good.

Offsetting to the right a little creates a little more spacing.

Operating around the world, it's very common to have other aircraft pass directly over or under us, because they're following the same airway that we are, precisely. It's very common for crews to offset a mile, two miles, or three miles off track, paralleling the intended course.

This isn't necessary, but it's good practice, or technique. If each aircraft approaches a waypoint from opposite directions, each offset one mile, then they've gained two miles of separation. This is useful.

In any case, for planning purposes, generally you plan from waypoint to waypoint, until your journey is complete. You can begin and end your journey with a departure procedure and an arrival, and simply plan your flight to a fix on the arrival, then name the arrival, if you like. Likewise, you can simply use an airway and name the airway, rather than citing each waypoint in the airway. You can enter and leave the airway at any point; simply file to a point along the airway (needn't be a VOR), and at some point when you want off the airway, file from the point you want off to a new waypoint some place else.

As others have noted, in Class G, you're fairly free to do as you will because it's uncontrolled.

[Johnm]

I suspect that one or two folks have the lost the bit about this trip being in solid IMC.

I fly IFR/IMC in class G a fair bit around Southern England and there's a lot of complex controlled airspace, VOR/DME is generally accurate enough if it's on your route, but otherwise GPS is essential as far as I'm concerned.

I'd also avoid IMC flight without a radar service unless it wasn't available.

That said I've got two VOR/ILS a DME and a ADF and I'll have 'em all tuned idented and selected if they're available as well as a chart on my lap. I see no harm in having belt, braces and a piece of string to hold up one's trousers in IMC.

[Fuji Abound]

That said I've got two VOR/ILS a DME and a ADF and I'll have 'em all tuned idented and selected if they're available as well as a chart on my lap. I see no harm in having belt, braces and a piece of string to hold up one's trousers in IMC.

On that I think we would all agree. You will not catch me flying around such tight airspace without a GPS and I will always take a traffic service if I can get one. Doesnt mean I wouldnt fly without a traffic service (although these days I have TAS and I am a lot more comfortable with it), and it doesnt mean I wouldnt fly without a GPS if I had to.

Last year I did about a quarter way across Europe without almost anything after the GPS failed on the aircraft I was reluctantly flying and the VOR was a awaste of space most of the time. I did ask air traffic to keep a watchful eye on my progress however!

[Miroku]

I use airways intersections e.g. ORTAC, ROLEX, etc.

Are these the places I can see if I look in AIS-IAIP-en route charts-lower ATS routes?
If so, is there a better chart available? I still couldn't find ORTAC or ROLEX.

[flybymike]

Quote:
one can pick up airways intersections (they are also in the GPS database so they are handy).

I0540, would you mind expanding on this please? I've not heard of this before. I'm assuming this would work on my Airbox Clarity?

No idea whether IFR reporting points are shown on the Airbox units but they are shown on both my VFR Garmin units. They are all five letter names and there are loads of 'em!

[IO540]

Are these the places I can see if I look in AIS-IAIP-en route charts-lower ATS routes?
If so, is there a better chart available? I still couldn't find ORTAC or ROLEX.

Some of them show up on the CAA 500k map - e.g. look at the boundary with France and you will see ORTAC GARMI NEVIL SITET etc etc. all along that line.

Over land, few if any are shown.

They are on the IFR (e.g. Lower Airways) charts but those are useless for non-airways flight (they are pretty naff for airways flight too ).

They are fortunately found in Navbox and Flitestar. I don't know if Skydemon shows them (it must do) and I don't know if Flitestar VFR shows them. I think PocketFMS also shows them.

I use Navbox for low level flight, in conjunction with the printed 500k chart.

As a superficial example, Elstree to Bembridge could be done as

BOV BENSU VAPID HAZEL

BOV WOD MID is done wholly on navaids but goes right up to the LHR CAS (not good).

Anyway you get the idea. These intersections are really handy, if you are using a PC to do the plog. I've been doing all low level flights this way since the day I got the PPL.

Handheld GPSs have them in the database.

[Miroku]

Got it now, many thanks for the explanation. It's a pity that these are not marked on land on the half mill chart.

[Pace]

One should never use user waypoints in a GPS, due to the potential for data entry errors.

I Use them all the time There are many reasons you may use a user created waypoint. Obviously if you have a VOR NDB Intersection etc use those to load into your GPS but sometimes you have to create your own.
The main point with user created waypoints is to be aware that there is room for error and never trust one item back it up! Ie in the simplest term is the waypoint in the right direction? Is the DME readout matching to the map distance?
Pilots often use user created waypoints for approaches based on NDB DME.
The GPS is more accurate and not prone to so many errors! used together to back one another up you can then fly with more accuracy using the GPS but backing up the GPS with NDB/ DME.

Flying a straight line across a ridge of high terrain you may have weather or strong winds where its not passenger friendly to plough over them. Use user created waypoints to avoid the hills but dont fly them with blind faith. Check!

Rely on one item in any nav piece of kit and you are asking for trouble.
I am sure flying an ILS you dont blindly trust the ILS but check spot heights on the chart against the glideslope.

I have known of pilots who have flown frozen needles blindly!

Even there its useful to have the GPS to confirm the localiser centre point matches the GPS inbound.

Flying back from INDIA in an old wreck of a Citation and having been assured the GPS had the whole world installed Europe was not there.We had to load every single point using lat long coordinates for the complete trip from Saudi Arabia (Yikes) but we double checked and confirmed each item and then checked againt the maps. We only got one out of about 60 points wrong and soon identified it as being wrong.

Pace

[IO540]

Sure it can be done but whether I would recommend someone new to IFR to generate a load of user waypoints in his flight planning program, and then litter his GPS memory with them, that's a different story.

If one has a GPS which the flight planning program will download to (something to check out before buying either of these items) then the user waypoints should transfer fine into the GPS, but if you make a habit of creating them, you will end up with so many that mistakes are possible.

We all speak with our own experiences and since 2001 I have had to create user waypoints for

1) La Axarquia (LEAX) in Spain, in 2003. By 2004 it was in the Jepp database.

2) Messalonghi private airfield in Greece (near the MESSI intersection), in 2010.

3) A DIY GPS approach into a certain UK airfield. I developed a very nice IAP, with a missed approach, for that place (lots of hills nearby) which uses several GPS waypoints, all on the same inbound track (as is the IAF; there is a procedure turn if you come in from the other direction) and all those up to and including the FAF (the TOD) are double-checked against a nearby VOR/DME. I flew it a few times in VMC but never had a reason to go there in bad wx again...

I wouldn't consider these a good reason for using user waypoints for hacking around the SE of England

[Pace]

I wouldn't consider these a good reason for using user waypoints for hacking around the SE of England

10540

Why not? They are more fiddly but as stated as long as you double check putting them in. Confirm their positions using other aids and LIKE using any other aid dont trust it blindly! whats the problem?

Pace