Diverting to an alternate

[FenderManDan]

So i am flying (note: simulated exercise) and some bad wx for example is forcing me to plan a diversion, backtrack is not possible because home base is under the bad weather too. What are good rules of thumb to remember?

Note: i am a low timer.

Cheers

Dan

[Go Juice]

You should always have an idea of where you'll go if the wx craps out/ mechanical / sick pax.

Also you should have a pretty good idea on how long it's going to take you to get there and if you have the fuel for it. Before you leave, pick 2-3 check points and find out what a good alternate would be for these points. Then calculate distance, time and fuels.

That way, when shit really hits the fan, you will have a lot less to figure out and life will suck less

Fly safe!!

[shamrock104]

Slow aircraft down, lean Mixture, Circle, Circle, Line- First circle over your current position, second circle for destination, then draw a line between the two locations. When you have this done you can make your halfway mark, heading to fly etc etc. Not really a "rule of thumb" but the main thing is to keep it simple as above as your workload will be increased a little. After you have completed the above its now time to consult the CFS for your airport of choice. Hope this helps.

[Colonel Sanders]

Press the "Nearest" / "Direct" buttons on the GPS, and
make the bearing and track numbers the same.

Figure out a safe minimum altitude. Your GPS might
be able to help here. If all else fails use the big blue
numbers on the VNC.

Figure out the elevation, runway layout and comm
freqs of the alternate airport. CFS if you're old school,
or press the "Wpt Info" button on the GPS. Bonus
points for noticing right vs left circuit traffic.

[Shiny Side Up]

Fortune favors the prepared mind.

[FenderManDan]

Cool, thanks for suggestions. One more note, the bugsmasher c172 does not have a GPS, it is well oiled 24000 TT 40 year old machine with rough paint job, and the "old school" avionics except the newer mode c transponder.

What can I say. "It flys better than it looks" (as Han Solo says).

Do you allways plan the routes according to and/or taking the consideration of alternates?

[DanWEC]

Rules of thumb...in the order of what I remember....
You can use the instructor or examiner as a resource. He can grab you the CFS, etc. Not much more though.

Bad Weather- Oh crap.
Look at the ground, get a solid idea on where you are.
Carb Heat (if in bad wx, could be skirting cloud- icing conditions). Leave it on.
Slow down, 1900 rpm or so. (Correct me if that's off) Trim.
Set up to fly about 30 second-1 minute legs in a box around the point on the ground where you know you are while you do your map work. You don't want to do a steady circle because of the chance of a spiral dive if you aren't diligent.
Take a breath.
Look for alternate on map. Check CFS for suitablilty and freqs.
Turn.
Align your map so your new destination is up. Always do this.
Draw line on map to dest and mark a halfway point. CHECK FOR OBSTRUCTIONS/TERRAIN/TOWERS
Choose an enroute altitude, or just stay under clouds.
Do "5 mile per thumb width" for distance. (Though mine is 6.. know what yours is!) Write it on the map.
ETE is 2/3 the distance, in minutes (15 miles= 10 minutes) Write it on the map, and the time to your halfway point.
Fuel- Enough? I used an easy 3/2 of time, minus a decimal place. Simple. Eg- 10 miles? 1.5 gallons. 20 miles? 3.0 Gallons.
Turn.
Bearing- use a nearby compass rose on a VOR. Align your pencil with your track, and drag it over to a VOR. Write down your bearing on the map. Rough idea where the wind is coming from? Give a rough mental correction.
Call up FSS and inform them of your intention, and ETA in ZULU time. "GABC to divert to blah due to weather at original destination. ETA xxxx zulu". Ask for wx briefing if possible for up to date winds. Get nearby altimeter settings if the destination is uncontrolled/no FSS. This step, to me, is pretty important and almost no instructors I know of focus on it- wx changes usually mean changes in pressure. You "should" be able to see the ground clearly, but you never know.
You're done, mostly. Now the almighty 5 T's to get you on your way.
Last Turn, and:
Time, turn, throttle, talk, (to alternate if possible for altimeter setting), twist (altimeter and DG set)

Everything should now be written down on your map and you should be on your way. Next job is the waiting for the halfway point. Arrive on time? Sooner or later? Adjust your ETA with FSS by double the current time difference. Left/Right? Adjust track accordingly using drift correction methods. If it's halfway, just double the approx bearing of error to left or right.

I might have missed something, someone else might have a better order, but that should be about it for a good compromise of quick and dirty and well planned.

[Trematode]

Assuming you're looking for help with the flight test exercise:

Hate to add another acronym to the pile, but:

H - Heading
A - Altitude
D - Distance
T - Time
O - Octane

Useful for remembering the items you'll have to quickly figure out for your diversion exercise.

FYI, from what I've been hearing lately examiners (at least in my area) have been trying to discourage any kind of circling while you figure this stuff out.They want you start your diversion as soon as its reasonable, and figure out the finer points when you're already established enroute.

With that said, if we're talking about having to do this in real life.... an ounce of prevention, pound of cure, etc. etc.

I don't think there's any real good excuse to get caught in the weather if you're flying in an area with ample weather services, especially if it's just a recreational flight. Check, and double check the weather. Make sure you know what it's doing and what you can expect before you even go. Don't be timid about calling the flight off -- you're not flying to save lives, or keep customers happy -- save it for a nicer day.

[niwre]

I don't think there's any real good excuse to get caught in the weather if you're flying in an area with ample weather services, especially if it's just a recreational flight. Check, and double check the weather. Make sure you know what it's doing and what you can expect before you even go. Don't be timid about calling the flight off -- you're not flying to save lives, or keep customers happy -- save it for a nicer day.

That is nice and dandy but it just happens sometimes. I've been stuck in VFR where my destination became IFR. METAR said is ok to go, the TAF was CAVOK for the whole TAF, the GFA again was perfect VFR conditions and well darn those pesky AIRMETs/SIGMETs but again none issues until I was more than an hour and a half enroute. You can double check and triple check all you like but sometimes weather happens. Never did I enter the IFR but I had to divert an hour to my closest suitable airport that has 100LL and paved. But you are right in the fact that one should never be timid in calling off a flight.

FYI, from what I've been hearing lately examiners (at least in my area) have been trying to discourage any kind of circling while you figure this stuff out.They want you start your diversion as soon as its reasonable, and figure out the finer points when you're already established enroute.

Straight from the PPL FTG
"Ex. 23D – Diversion – The candidate is expected to initiate the diversion without undue delay by quickly determining a heading and a time enroute without wasting too much time in a holding pattern."

They're stamping it out because TCCA is telling them to. But it all comes down to are we as an industry developing thinkers or reacters (dont think it's a work but meh!). Once you know where you want to go (and a logical destination) fly a heading that makes sense and like you said "figure out the finer points when you're already established enroute."

[iflyforpie]

The whole point of a diversion is that it is down and dirty. They've wrung you out with nav logs, dead reckoning, and revised ETAs, now it's time to see what you can do in your head.

I still remember this from my PPL:

Dot dot line
Distance, heading, time
Make a call and you'll be fine

Find a nearby, prominent feature, find where you want to go, draw a line and compare it to a compass rose or guesstimate keeping in mind variation. For short distances you've got the idea with your fingers, but diverting to places you can practically see is a no brainer. A narrow hand span is about an hour's flight in a 172, a wide one an hour's flight in a 182. Also know the 'practical' speed of your aircraft, 100 knots for a 172, 120 for a 182. 182s make the math real easy because it is two miles a minute, 30 every 15, etc.

You should always be aware of your fuel status. You wrote down the time you took off, you should know what time it is currently, and you should know the time to dry tanks you took off with. There should be no fumbling with fuel numbers when you divert.

While they may not encourage circling, there is no restriction against slowing down to get organized. 172s like ten flap, 70 knots, and about 2000 RPM with carb heat. 182s like 20 flap, 80 knots, and about 18 inches give or take at cruise RPM. These are excellent speeds for safe minimum radius turns at 30 degree bank angles and have each plane close to Vy should you need to use it.

I don't know where you are flying, but here in the rocks, diversionary airfields are always on my mind. Within an hour's flight of Invermere, I've got Fairmont Hot Springs, Radium Hot Springs, the Royal Antler Ranch, Bugaboo Lodge, Cranbrook, Golden, Elko, and a hodgepodge of decommissioned and private strips I can land on. When I cross to the west side of the ranges and am at the mercy of the passes closing coming back, I've got Kaslo, Crawford Bay, Creston, and Nelson. Diversions here rarely involve a straight line, so I always have a one hour reserve.

[Big Pistons Forever]

Cool, thanks for suggestions. One more note, the bugsmasher c172 does not have a GPS, it is well oiled 24000 TT 40 year old machine with rough paint job, and the "old school" avionics except the newer mode c transponder.

What can I say. "It flys better than it looks" (as Han Solo says).

Do you allways plan the routes according to and/or taking the consideration of alternates?

I just finished a PPL for a guy. I told him here is how to do the TC BS navigation so you can pass your flight test. When you are done go buy a GPS and I will show you how to get from A to B in the real world. The day after his flight test he picked up a GARMIN 295 for $ 300 dollars. It is not as spiffy as the latest and greatest but works perfectly well and the price was definitely right.

Anybody who wants to fly outside the local area and does not avail themselves of the real time accurate information that a GPS provides is IMO stupid. GPS makes flying safer and easier and the "nearest airport" function can literally save your life. Yes there are caveats with VFR GPS use and you always need to keep your map open and your finger moving along it, but it is time the flight training industry and TC get with the program.

[niwre]

Yes there are caveats with VFR GPS use and you always need to keep your map open and your finger moving along it, but it is time the flight training industry and TC get with the program.

Amen to that... but too funny that by chance that I head this today on FSS freq "My GPS conked out so Im not really sure where I am but im following the hiway in"

But I fully agree that TCCA needs to get with it and get friendlier with the GPS thing.

[Colonel Sanders]

My GPS conked out

Should be a total non-event. After making the bearing and
track numbers on the GPS the same, note your heading. And
note your ETA.

If the GPS dies, hold the heading and look down at the ETA.

This should not pose an intellectual challenge.

All navigation is fundamentally based on holding a heading,
and time, regardless of what radios you have in the panel.

PS A spare set of batteries - even better, aircraft power -
goes a long way to making the GPS more reliable. Get
the lithium batteries. They are awesome.

[niwre]

My GPS conked out

Should be a total non-event. After making the bearing and
track numbers on the GPS the same, note your heading. And
note your ETA.


All navigation is fundamentally based on holding a heading,
and time, regardless of what radios you have in the panel.

You will never get a disagreement out of me from those statements, but there are way too many GPS only users out there who uses it as their only means and becomes a huge crutch to them. That's where your desire of TCCA becoming more warm to the VFR GPS thing. With proper training we would not see problems like that.

[5x5]

One thing I do is to look along my route and make a two column list of the airports I'll be passing within about 20 miles of my track.The left column for airports that will be on my left, the right column for those on my right. I'll list the ATF and rwy #s at least and any other info I feel like at the time. Basic and easy to do, takes a couple of minutes only. Then, as I fly past each one I'll check them off and maybe add the time I went by.

It doesn't take much effort at all and serves to keep me at least somewhat aware of where I am on the map and a sense of roughly how far I am from the next nearest airport. It's not a time intensive task to prepare or manage in flight. When things are great and you're flying along fat, dumb and happy it's nice to have something to do anyway. And if things go bad, and you're no longer happy, it can be a real help in keeping relation to where you are and where you want to go.

All navigation is fundamentally based on holding a heading,
and time, regardless of what radios you have in the panel.

That's true for the straight line you are currently flying. The difficult part is when you have to turn off the present straight line and establish a new heading. If the GPS is broken, that is where the difficulty starts.

[Beefitarian]

Don't worry I know GPS is wonderful easy and you can't live without once you use one.

I seem to be the only one that likes the challenge of pencil, time piece, VNC, fuel/time log. It's part of a fun puzzle you only get to do flying small singles. There's too many signs driving even in strange countries. I would use a GPS for a real life diversion but I would also be roughly following along on my paper chart. GPS dies? Carry on.

The only time I ever actually diverted. I was fourtunate enough to be well away from any mountains. Saw the weather moving in over my planned destination, knew where I was, looked up the nearest airport, turned toward it, made a rough calculation of ETA, called Terra Haute FSS, "PA-28 C-G... I'd like to amend my flight plan diverting to Crawfordsville..." stayed clear of the clouds and no problem.

I also like to have at least a 45 minute reserve. I alway think, "What if the headwind is a bit stronger than they say, I actually need to hold, divert or something?"

[Shiny Side Up]

GPS makes flying safer and easier and the "nearest airport" function can literally save your life. Yes there are caveats with VFR GPS use...

Caveats indeed. The main one being that the GPS is only as smart as the user. Suprisingly (or maybe not so much) people lose their way all the time despite the aid of one of these wonderful devices. To make optimal use of the GPS you still need to have that basic nav ability that doing it "the old" way provides, and while its disparaged by many it still serves that purpose. Universally students who take the time and are interested in how old map and compass navigation works learn how to use the GPS quicker and more efficiently. Its a step in a process which does make sense in the relationship factor. You'd be suprised (or not) at how many pilots don't know the difference between track, heading, and bearing. Ground speed, true airspeed, and indicated airspeed since they've let their knowledge lapse following the magenta line. Got an earful from another instructor a few days back who insisted his interpretation of his GPS was correct which sort of flew in the face of stuff like which way the windsock was pointed. Insistently he makes a lot of tailwind landings for some reason.

There is the increasing assumption that the "device is always right". Technically it always is, its the user who uses it or reads it wrong. Most common GPS use errors come from the user input side of things - largely because they have no capacity to tell when they've screwed up. Their brain is wired in series with the device rather than parallel.

[Colonel Sanders]

I seem to be the only one that likes the challenge of pencil, time piece, VNC, fuel/time log

I left that challenge back in the 1970's and 1980's where it belongs, before all the Good Stuff (tm) was invented.

[Beefitarian]

all the Good Stuff (tm) was invented.

Like single wing aerobatic planes.

[Colonel Sanders]

How true. My airplanes have no left wings.

[Beefitarian]

Really, or is that the absinthe talking? I was referring to the extra 300.

[Big Pistons Forever]

GPS makes flying safer and easier and the "nearest airport" function can literally save your life. Yes there are caveats with VFR GPS use...

Caveats indeed. The main one being that the GPS is only as smart as the user. Suprisingly (or maybe not so much) people lose their way all the time despite the aid of one of these wonderful devices. To make optimal use of the GPS you still need to have that basic nav ability that doing it "the old" way provides, and while its disparaged by many it still serves that purpose. Universally students who take the time and are interested in how old map and compass navigation works learn how to use the GPS quicker and more efficiently. Its a step in a process which does make sense in the relationship factor. You'd be suprised (or not) at how many pilots don't know the difference between track, heading, and bearing. Ground speed, true airspeed, and indicated airspeed since they've let their knowledge lapse following the magenta line. Got an earful from another instructor a few days back who insisted his interpretation of his GPS was correct which sort of flew in the face of stuff like which way the windsock was pointed. Insistently he makes a lot of tailwind landings for some reason.

There is the increasing assumption that the "device is always right". Technically it always is, its the user who uses it or reads it wrong. Most common GPS use errors come from the user input side of things - largely because they have no capacity to tell when they've screwed up. Their brain is wired in series with the device rather than parallel.

GPS is a tool. Like any tool there is certain base line knowledge that is required before you start to use it and the utililty of the tool is greatly increased if you get some practical training on best practices for its use. Unfortunately TC and most instructors are fixated on teaching only that which will be examined on the flight test and therefore ignore or disparage the use of GPS.

Frankly I am getting tired of the don't use the GPS because it can fail argument. If you truely believe that, then you should always fly with your Airspeed Indicator covered. You can infer airspeed by power setting and attitude and the airspeed indicator could fail so better not take advantage of real time airspeed data, right . Same with the GPS " No way do I want accurate continuous, track, distance, GS and ETE data when I can get the same data some of the time, with less accuracy and wth a whole lot of extra work .

Like CS said if it does fail, fly the heading that was maintaining track and since you where keeping track of where you are on the map you will have navigational situational awareness. So in the context of this thread, something comes up and we have to divert Now.

We could circle while frantically scan the map for places to go, then draw some wobbly line on the map, make a guestimate of the course, use a calibrated thumb to more or less find the distance and then do the math for the ETE/ETA......or

We could push "nearest airport" on the GPS look at the list on the screen, pick the best one and then hit direct to and get exact bearing, distance and ETE/ETA.

Care to guess which one I think is a safer better way to go when the pressure is on ?

[Beefitarian]

"Don't use it in case it breaks?" Personally, even though I don't disagree with a person being that prudent. I think if you are that afraid of disaster stay home.

GPS is spiffy and from what I recall simple enough to have chugging away in the back ground if you choose to navigate manually.

You're right it's just plain and simply a great tool. If I can navigate manually why not use it to check my work. It would be reckless and dumb not to.

I think if you can't navigate you better have GPS and if you just hate to navigate it is some what acceptable to rely on it.

[Colonel Sanders]

My frikken phone has a GPS with moving map which is
far more accurate than the IFR-approved LORAN
panel-mount units, back in the day. It makes an
IFR-approved ADF look like a bad joke from a 19th
century sailing ship .

I realize that people have to be taught to the flight test,
and learning to use heading and time to navigate is a
fundamental skill, but not teaching a PPL about GPS is
foolish, because that's what they're going to use as
soon as they finish their training, because of it's incredibly
low cost and superb accuracy.

I just see this huge, yawning reality chasm between
the 2 hr "draw the lines on a map and prepare a flight
log" for flight training x/c, and how PPLs never do that
stuff ever again, and use a GPS to navigate everywhere
afterwards.

Why not teach them about GPS, too?

[Beefitarian]

I'm going to go with, because GPS is simple enough to figure out. You're claiming you'd be happy to pay a guy to teach you how to use one, I would be surprised.

I suppose you could make manual navigation optional now.

I wish I had been forced to learn morse, because it's a skill. Since it was not mandatory, like everyone using GPS I'm inherently lazy, so I never bothered because in addition to it being difficult, I would have to track down Cat Driver to have someone I could use it with. Now that I can apreceate a skill like that I'm old and it would take years to learn.

I don't know why they are taking so long to approve GPS for everything IFR, that is totally different. I can't look through a cloud to see landmarks. The only time I did not have enough land marks was in eastern Montana where there is an area with no rivers and over 100 miles of space between anything man made including a VOR. If the cross wind had been stronger than anticipated somewhere along the way it would have been nice to have GPS there for sure.