In flight scenario

[brns2]

Say you had planned a flight from A-B. The weather at B was above the alternate minima when you flight planned.

Inflight you get the updated TAF and B now has broken cloud below the alternate minima, but not below the landing minima

What are you supposed to do enroute if you have enough fuel only to get to B or C (an alternate with wx above alternate minima), but not B then to C?

[FRQ Charlie Bravo]

Pop out a cabin window and become depressurised. Problem solved (unless WX drops to below Ldg minima and airport is no longer Acceptable).

Of course if you didn't catch the radio call then you wouldn't know better would you. Hmmm, business ethics...

Seriously though, it looks like you'll be spending the night (or getting fuel) at C. According to the blue book you can't legally "plan" (continue to plan) to go to B. I have thought about this one before but never saw it in any practice exams or on the real thing.

FRQ CB

[Mstr Caution]

There are other considerations:

1. Get a TTF which may have weather conditions above alternate minima at airport B.

2. Is sufficient fuel available to hold at airport B until such time as the forecasted conditions improve above alternate minima & thus not requiring an alternate from that time.

3. Continue to a point of no return for airport C & hope during such time an updated forecast becomes available to continue to airport B.

[QSK?]

brns2:What are you supposed to do enroute if you have enough fuel only to get to B or C (an alternate with wx above alternate minima), but not B then to C?Answer: Calculate a point of safe diversion. Go to: CALCULATION OF POINTS OF NO RETURN (PNR) AND CRITICAL POINTS (CP) (http://www.airsafaris.com.au/general_info/pnrcp.htm) and see section (5)

[brns2]

FCB... you made referancne to the blue book, i wasnt asking a question to do with ATPL planning, but was just wondering about it in a real life situation.

As I have had it happen to me before but always had an option of going to B then C.

But im just wondering if there is a rule that says you can continue to fly to B as planned as the TAF at the planning stage indicated above alternate minima wx.

That really does make things difficult...

What i you had passed your PNR to go C? and then ML CN say "all stations B, updated taf available" with the weather below alternate minima, but above landing minima?

[Tempo]

If you have passed your PNR and you cannot divert to legally meet the inflight requirements then all bets are off. You are committed as such to destination (or another location) without meeting the legal inflight fuel requirements. Remember, just because the wx is below alternate minima it is probably above landing minima so chances are you will get in off the ILS (or NPA). You cannot plan for every situation (unless of course you take destination + alternate + Tempo + etc etc)

[biton]

If you haven't yet reached the PNR for B an C, you don't have any further weather updates, you don't have fuel to hold at B, and the weather at B is deteriorating why would you take the risk and press on to B when you have a perfectly good alternate in C? Yes, B is above landing minima NOW but given the forecast has already gone from ok to below alt minima- not a good trend- and you've got NO contingency fuel when you get there (as per your example), why risk it unless you had no other options?

An AirNZ skipper told me this exact scenario happened to an AirNZ 747 crew many years ago while crossing the Tasman. They pressed on to the PNR and beyond and found themselves sucking plenty of seat into their asses when they reached the other side.

Watch the weather TRENDS

[The Butcher's Dog]

“Practically speaking?”……you might try to push on to B – chance your arm- and be successful with an approach at B, you got lucky. This may be a circumstance driven decision where NO alternative option is available.
However, continuing to “B” conducting an approach, missing out and now committed to either continuing descent below minima (because there is now no other option) or heaven forbid some other kind of approach to ward off a powerless CFIT, (sounds fun:O) is a real likelihood.
Risk minimisation, avail yourself of options – go to C and everybody gets home at B, albeit a little later. Those other “practical” industry alternatives are not worth it.

[FRQ Charlie Bravo]

Wait a minute so all that PNR stuff isn't just academic...

I'd have to agree with those who've ultimately said go to C. Yes keep going to B hoping for a better forecast until you get to the point where you will have to divert to C to arrive with min legal FOB.

FRQ CB

[compressor stall]

Not so academic...

I have been flying to YKOW from YBCS with one way fuel (no alternate) as it was way above the ALT minima and no holding. Just before half way out CTR called me with a TAF AMD that now had YKOW, WP, Pomporaaw etc - all way below landing minima for their respective approaches. There was nowhere else to go.

Fortunately I still had enough fuel to get back to CNS - just.

[Howard Hughes]

Always have an out!:eek:

Pull the taps as soon as you sniff a problem, that way you buy yourself more time!:ok:

[FRQ Charlie Bravo]

Excuse my ignorance but what do you mean by "pull the taps"?

FRQ CB

[Chimbu chuckles]

I am reminded of the time a few decades ago sat in the run up bay for 11L at YSBK next to a Baron on one of 'those days'. Grnd calls said Baron and tells him bad news about destination alternate now itself requiring an alternate and requests new alternate/endurance...this happens twice more over a couple of minutes. Finally grnd asks him where he is getting all this fuel..."The same place you're getting all these weather reports":D

Laugh? I near shat myself.

To answer the first post...learn how to do 'last point of safe diversion' and if beyond that point when the news arrives continue to destination. What other choice do you have?

Edit: I just had a peak at the link above and it is #5 in Chesty's piece.

[Howard Hughes]

what do you mean by "pull the taps"?
Reduce power to LRC or even as low as holding speed, it will buy you a bit of time (in some cases a lot of time) to assess your options, perhaps even enough time for conditions to improve. In most cases a slightly longer flight will keep the passengers (and boss) happy, whereas a diversion causes difficulties for everyone.

This applies just as much to large pistons as it does turbines!:ok:

[Capt Wally]

I think our learned friend 'HH" means to reduce pwr, to set up LRC (Long Range Crz), therefore buying time that's what "pull the taps" means, well it is to me:ok:

The answers are varying here as to what's best to do because flying is not an exact science when WX is taken into account. If you have the chance bug out to 'C' but if not then I would if possible decend to LSALT i& remain there enroute to yr original destination all the while seeking to further decend in VMC & increase yr chances of a landing elsewhere.


CW

[ITCZ]

Wait a minute so all that PNR stuff isn't just academic...
:uhoh:
“Practically speaking?”……
:bored:

Us aussie pilots look at 500hr pilots getting jet jobs in Europe and Asia, and shake our heads at the idea of 200hr "MultiCrew Pilot Licences" operating as FO's in medium and large jets. Where is the real world decision making, the experience?

A GA background is hard won real world experience -- but there is frequently one big drawback. You have to de-program a lot of small time, GA charter thinking for many of these guys when they turn up to fly a jet.

If you aspire to earn six-figure salaries flying big iron, then put your GA and Low Capacity RPT experience into perspective.

Airline passengers and airline employers expect their pilots to
Know all the rules (the blue book(s), if you like)
Fly to the rules
Use their experience to solve problems safely, without breaking the rules


If you make it as far as interview/type rating/line training, the worst thing you can do to yourself is make a comment like "but in the real world, I would..." That will either be the end of your airliner job interview, or be a 'red flag' moment for your instructor.

[Howard Hughes]

I'll give you another scenario, one which has actually happened to me. Flight planned from A to B (your home base and approximately one hour flight time), weather at B requires an alternate, so A is the alternate. You carry enough fuel for the flight A to B, two approaches at B, then a return to A if required. On arrival at B the weather is below minimas due to a heavy rainshower, you carry out your two approaches with no success then divert back to A.

Ten minutes into your diversion, the boss gets on the radio and says, "the weather is now clear and two aircraft have just landed, turn around and come back". What do you do?:ooh:

[FRQ Charlie Bravo]

Great way of putting it ITCZ (is your name for the Convergence Zone or were your parents just mean?:)).

I meant the academic thing with a bit of tongue in cheek (in fact what I enjoy most about aviation is being at the sharp end of the practical application of academia such as maths and physics) but what you said made me realise that I've probably become "one of those pilots" who can be tempted to think that they know better than the regulator/authority/convention.

Not that I'm a blatent rule breaker but introspectively (and possibly too frankly) I do tend to think about ways to maximise returns whilst accepting the minimum level of safety (although never below that level i.e. never "unsafe"). Along those lines however, I'm much more brazen on the ground and a bit of a safety-chicken in the air.

I've been guilty of thread drifting lately but I think that this is relevant to brns2's original question (at least in theory anyway). Perhaps when I can gather my thoughts on GA deprogramming a bit more I'll pose a new question in a new thread.

Excellent post ITCZ, you've really made me think (and hope that I haven't been too tainted by trying to be a productive GA pilot).

~FRQ CB

[FRQ Charlie Bravo]

HH,

If the boss is an approved observer then legally I suppose that you'd be ok (provided that you still had fuel to meet the statutory reserves). However, I would have to say that I would also question the bosses' motives. If he/she is always pushing pilots too far then bugger that.

I can think of one particular example where my CP flew from Home to A then took pax to B (flew past home to get there) with no joy twice then diverted to Home (16 minutes) where the xwind was way too much (I watched from the ground with bated breath). The boss was next to me on the radio telling him to get it down now, he "politely" declined and heard from another AC that A was open again so diverted back to A. I think he probably landed with a bit less than reserves intact but the forecasts were definitely wrong that day.

At the end of the day the boss was angry about all the extra flying but had absolutely no grounds to do anything about it (and that would have held true for a line pilot too but probably only because the CP would have stepped in).

~FRQ CB