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standby to see BOM include a PROB 30 FG..on every TAF for the rest of winter!!....It covers BOMs arse.
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Fact of the matter is I work for an airline that can't justify the purchase or hire of GPU's at each port resulting in regular maintenance burns in excess of 500kgs, it would take me weeks of carrying an extra ton here and there over 30 minute sectors to equal that wastage. |
When I was training I was told that if the prediction for something to occur was equal to or greater than 50% then it would appear on the forecast without a PROB.
Never seen that one in writing though so I'm not sure how true it is |
Originally Posted by Kodachrome
When I was training I was told that if the prediction for something to occur was equal to or greater than 50% then it would appear on the forecast without a PROB.
Never seen that one in writing though so I'm not sure how true it is Crikey advises that the ATSB have announced an investigation, as per the following links. ATSB investigating Virgin Mildura fog incident | Plane Talking Investigation: AO-2013-100 - Low fuel diversion involving Boeing 737-8FE, VH-YIR, Mildura Airport, Victoria on 18 June 2013 |
Originally Posted by AIP Gen 3.5
12.15.3 When thunderstorms or reduced visibility due to fog, mist, dust, smoke or sand is forecast but the probability is assessed at 30% or 40%, the terms PROB30 or PROB40 are used respectively. INTER and TEMPO may also be used with a PROB for thunderstorms. If greater than or equal to 50% probability is forecast, reference is made to the phenomenon in the forecast itself not by the addition of a PROB statement.
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Can l ask the question how has qantas come out as heros?? Did they not land in thick fog of a npa below the minima ...maybe a little more fuel and no mayday or brace ...or was it clear when they touch down???
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Did they not land in thick fog |
Joblogs,
You werent there so assumptions like that are completely out of order, enough said... |
Looking at Flightradar 24, the Virgin aircraft made the decision to divert to Mildura first, with the Qantas aircraft about 5 mins behind. Note, the Qantas did a few holding paterns to the east of Adelaide.
The Virgin aircraft disappears of Flightradar first with the Qantas aircraft still in view for another 3-5 mins. Based on this it would appear Virgin arrived in the Mildura area first, but Qantas who were behind them landed first??? |
Timing
Unless I'm missing something, the timing seems odd:
- YPAD TAF updated at 172100 - Diversion occurs at 172300 I find it hard to believe a crew, on discovering that their destination went below Alternate minima, continued with either no alternate (it seems they had no planned alternate based on them never getting near Adelaide) or with an alternate allegedly below the alternate minima. So if they didn't know their destination was PROB30 two hours before they diverted - why not? The layers of the cheese should have been: - ACARS updates - company operations department - ATC (would this warrant a Hazard alert? I thought they were for METARs going SPECI?) Everyone else seems to have turned back (except the QF - where did he come from? Did he also not get the message?) UTR |
Underneath the radar,
The most logical thing to do in that case would be to continue toward your destination, work out a PNR to a suitable alternate with a comfortable margin. If your destination is socked in at your PNR - go to your alternate. PIC 101. I'm only speculating but it looks like thats what they did in this case. Diverted to MQL only to find enroute, it was now fogged in. Very little time to make a decision to go back to ADL where you know you're landing below minima. Kudos to the crew. Safe outcome! |
UTR,
The Qantas aircraft came from SYD and it arrived in the ADL area before Virgin and held to the east. As I said in my post above the Virgin aircaft, diverted towards Mildura first and the Qantas aircraft left it's holding and followed about 5 mins behind Virgin, but some how it landed first in Mildura. I'm not knocking any of the crews (Qantas and Virgin), I'm just stating what the radar (via Flightradar 24) showed. There must have been a reason why Qantas landed first, which should come out in the ATSB investigation. Based on what we all know at the moment, I say well done to all crew. |
All very interesting reading & much can be learnt for us all.
Few good questions being asked re Prob of FG. As has pretty much been alluded to hear any greater % of fog beyond 30 or 40 the relevant documents states Fog, full stop. In a way there's a qualified met man in all of us drivers, we had to do Met along the way so apart from the legal side of things ALL pilots ought to be making fuel calcs to suit their understanding of the pending WX at the destination. We've got a high press over us ATM with wide spaced iso's & clear night skies with light winds at Grnd Lvl along with being bloody cold & no split between temps, that tells us that this could get bloody ugly re Fog. I know that I wouldn't trust the Met man (no offense Met man) as far as I could throw him with those conditions lurking. Flying's bloody dangerous even on a Cavok day ! Wmk2 |
FWIW
From the BoM Aeronautical Services Handbook (Operational Manual for the Provision of Aviation Weather Services in Australia). Investigations The Bureau prepares reports in relation to aviation accidents and incidents, usually in response to requests from government agencies responsible for aviation safety and from the aviation industry. The principal types of reports are: a. Meteorological information for Aviation Safety Investigation Reports (ASIRs), and b. Aviation Meteorological Incident Reports (AMIRs). Meteorological Information for Aviation Safety Investigation Reports (ASIRs) The Australian Transport Safety Bureau (ATSB) has the primary statutory responsibility for investigating aviation incidents or accidents. The Civil Aviation Safety Authority (CASA) may also conduct such investigations in carrying out its responsibilities as regulator of civil aviation safety. As part of an investigation into an aviation incident or accident, a request for meteorological information may be sought from the Bureau through the National Manager Aviation Weather Services (SRAV). Procedures for the provision of meteorological information are maintained by SRAV and can be found on the Bureau’s Aviation Weather Services intranet. All relevant information (charts, observations forecasts and warnings) is to be retained in the case of an incident or accident. Aviation Meteorological Incident Reports (AMIR) Aviation industry clients (such as regional, domestic and international airlines, and Airservices Australia) may request an AMIR when a meteorology-related incident has a significant adverse effect on its operations. Typical incidents include unforecast weather causing multiple aircraft to divert to other destinations; and significantly over-forecast weather requiring excessive fuel to be carried. The purpose of an AMIR is to review the service delivery aspects of the incident and make recommendations for remedial action where appropriate. Procedures for the provision of an AMIR are maintained by SRAV and can be found on the Bureau’s Aviation Weather Services intranet. In relation to Probability Forecasts Probability Forecasts, indicated by PROB%ddhh/ddhh, shall only be used if the estimated probability of occurrence is thirty or forty percent, and shall only be used with reference to thunderstorms or poor visibility (less than the alternate minimum) resulting from fog, mist, dust, smoke or sand, e.g. PROB30 0118/0123 0500 FG. PROB is included in the forecast before the RMK section. If greater than or equal to 50 percent, reference is made to the phenomena in the forecast itself, not by the addition of a PROB. INTER and TEMPO are not to be used with fog. Airport Weather Briefings (AWB) are provided for some capital city aerodromes and are used by both operators and Air Traffic Services. They are an extension to the TAF service aimed at expanding on the information provided in the TAF. The office responsible for the preparation of the TAF prepares the AWB. AWBs are issued in conjunction with the routine TAF but take a lower priority and are not amended or updated (except for the Code Grey component which can be amended as a separate product). Airport Weather Briefings may contain the following sections (as per local arrangement): Current TAF, TAF Summary, Thunderstorm Potential, Other Possibilities, Outlook, Code Grey, Issuing Officer and Notes. The TAF Summary is an explanation of the TAF, using plain language, with no jargon or acronyms. It may include the synoptic situation, local effects and reasons for forecast changes in weather conditions. The Thunderstorm Potential section highlights the possibility of thunderstorms occurring within a 20nm radius of the aerodrome reference point and is used for flight planning and air traffic management purposes. Phrases such as slight chance, chance and likely should be used instead of a percentage. INTER or TEMPO should not be used. The Other Possibilities section should include comments on other possibilities that may occur during the validity of the TAF. It can include conditions that have a less than 30% chance of occurring, or if there is an uncertainty as to the timing of an event. Particular attention should be paid to SAM (special alternate minima) conditions, noting that decisive phrases such as “conditions could drop to below SAM” are more useful to the aviation industry than “conditions could drop to SAM”. The Outlook section includes a brief description of the weather for the following 2 or 3 days based on the Public Weather forecasts. It should also include the forecast maximum and minimum temperatures where available. Code Grey information is included in the afternoon issue of the AWB. Code Grey advice is a special forecast service intended to supplement the routine 06 to 12 TAF. It is designed to reduce the operational impact, particularly on long-haul flights arriving the following morning, of later amendments to the 06 TAF. The service gives flight planners some insight into alternative weather scenarios being considered by the forecaster, and as such it provides early advice of a possible later TAF amendment. It is issued when there is a small but realistic chance of fog, thunderstorms, or visibility or cloud (BKN or more) below Special Alternate Minima. The probabilities used will be 5, 10 or 20% only. It would be interesting to see the afternoon issue for the day concerned as to whether Code Grey was included (previous say of course). http://reg.bom.gov.au/general/reg/ash/ASH.pdf |
Two year wait for a Basi report with no pressure, yet crews have less than a couple of hours to make these decisions under pressure with a high work load!
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Two year wait for a Basi report with no pressure, yet crews have less than a couple of hours to make these decisions under pressure with a high work load! There are 26 recommendations from the senate inquiry not the Atsb about the Norfolk Island accident. Crikey blog Damning Senate report on ATSB, CASA Pel-Air failings | Plane Talking |
Interesting situation you often face. You arrive at aerodrome A at 2300z with fog, with a metar saying fog clearing at 0000z. But 2330z is your aerodrome B diversion fuel cutoff time.. You have fuel in tanks to hold until 0030 and make an approach to A.
You have no legal obligation to divert at 2330 to B. Do you stay or do you go at 2330? |
You have no legal obligation to divert at 2330 to B. Do you stay or do you go at 2330? |
If you stay then you are betting the farm that the forecast is correct and we all know that sometimes it isn't. Pretty risky to stay IMO.
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betting the farm that the forecast is correct |
Virgin Aircraft 'Emergency' Landing
Originally Posted by UnderneathTheRadar
ATC (would this warrant a Hazard alert? I thought they were for METARs going SPECI?)
Prefix directed transmissions and broadcasts with HAZARD ALERT when a sudden change to a component of FIS, not described in a current MET product or NOTAM, has an immediate and detrimental effect on the safety of aircraft. |
When a meteorologist is discussing past weather he is a scientist. When he is discussing future weather he is a fortune teller reading tea leaves.
They can always use the magic word AMENDED and issue another forecast if they make a mistake or things turn out differently. I've been caught out by fog at MEL, I delayed my departure to get the latest TTF one night. Five minutes later I was taxiing with required fuel as there was no alternate requirement. Arrived with a 200' cloud base, reducing vis, aircraft ahead had gone around and nowhere else to go. Steam driven turboprop so forget auto land. I flew the most accurate ILS approach of my career, saw a couple of touch down zone lights at the last second and landed. The tower called to see if I had vacated the runway because the visibility was so bad.:hmm |
No roo not at all. As was eluded to re every time you flight plan you trust a forecast. In fact I'd hypothesise that the aircraft that went to mildura might have had enough fuel to hold until the fog ended on the metar but instead went to mildura, and had they remained in Adelaide would have gotten in drama free. Hypothesise I emphasise.
When you arrive at an aerodrome with tempo holding due TS, do you divert immediately if there's a cell you have to hold for? No you don't. If you've put fuel on to hold until a condition is forecast to clear , why not stick with the plan? If not what's the point of the plan? It's a judgement call on the day. Ill tell you I'd rather hold over Adl rather than go mildura, then auto land Adl if the metar is wrong. Provided I have the fuel to legally hold until the fog is forecast to end of course. |
Someone here mentioned that of course the BOM use historical data and current forecasts to figure out whats going to happen. My question is do they keep track of all the times its been wrong and as such give themselves the ability to see a short term local trend that may require the issuance of different Forecasts?
For instance, a few people have mentioned that recently they have noticed a trend in the area for unforecast fog, does the BOM keep data that would allow them to see the same thing happening 2 days in a row and cause them to automatically place a "Prob30" in based on these recent occurrences where their data is telling them it won't happen but recent observations have shown it occurred anyway? |
The forecasting has fallen over badly in the last couple of months. In a two month period I have personally seen unforecasted fog twice, overcast cloud below the minima and a unforecasted thunderstorm which was about 10 miles from the field but nowhere to be seen on a TTF 45 minutes from the destination . Additional to that is the two QF incidents, the Virgin incident plus a few more I have heard about on the grapevine.
Yes I can understand a few incorrect forecasts here and there but this is becoming an Australia wide trend. |
Yes Ixixly, yet another case of "this can be done by numbers". Just as with flying, you can't do it successfully only by what the book (or computer model) says. Smart, experienced humans are necessary to make it work.
It would appear that, despite amazing technology levels and what should be decades of experience build-up, the only thing that is preventing some really serious weather incidents is illegal Autoland and RNAV approaches (almost) to the ground. |
Every time you flight plan you do exactly that. You're example had one forecast being 100% correct or an emergency ensues. The reality of flight planning ( for me anyway) is that you only need one of two forecasts to be about 50% correct to operate safely. Completely different odds, much less risk involved. |
I agree that you wouldn't necessarily divert if you had fuel to hold. In fact that was my intention on the day. We could see the fog clearing slowly, tower was updating us on improving conditions, and I had fuel to hold well past the metar forecast clearing time. Even if I had to lose my Mel diversion option, I was more than happy in this instance , that the fog would clear in time for me to comfortably get in.
"In this case"... Being the crucial phrase. Horses for courses. But to say "you'd be mad" to remain at an aerodrome waiting for a forecast improvement to occur is way off base. |
Originally Posted by Capt Claret
(Post 7899391)
Crikey advises that the ATSB have announced an investigation, as per the following links. Investigation: AO-2013-100 - Low fuel diversion involving Boeing 737-8FE, VH-YIR, Mildura Airport, Victoria on 18 June 2013 |
If you've put fuel on to hold until a condition is forecast to clear , why not stick with the plan? If not what's the point of the plan? |
And that I did. I had 1.5 hours holding past the forecast clearing time. Please refrain from passing judgement on my decision making skills as I would not question yours without knowing the full picture.
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Good on you. I wasn't commenting on your post. I was questioning ejectx's hypothetical idea and a specific set of circumstances different to yours - of only carrying fuel to improve time plus 30 minutes and then sticking around after that when a diversion to a suitable airport is available. He made no mention of diverting to an airport with questionable wx in his initial post.
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Ah yes. But I agree with him that leaving yourself with only one option (ie staying ) is not always a risky decision if you are almost certain (ie you can see the limiting weather clearing) that the limitining weather will vanish.
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We need a friendly bean-counter.
It would be very interesting to know the financial cost to Virgin, not just in dollars out laid but also dollars lost, the dollars worth of time and effort that will go into the ensuing investigation, and the dollar amount of the publicity I've the issue, and then equate the sum of all these dollars with the volume of fuel it would buy. In other words, by saving a little on flight fuel burn by not carrying an alternate, how much have they lost? |
Not to mention bad PR......:D
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It costs about 10kg of fuel for an extra ton of fuel on an hour sector. Ie sweet F.A.
To put in perspective to carry 2 hours extra fuel over destination costs you about 40kg or 1 minute of cruise fuel. It's ridiculous the drive to push min fuel when it costs so little for the insurance of extra fuel. (737 figures) Or in dollar terms to carry 2 hours of insurance about $40 |
About the only time you have too much fuel on board is if you are on fire.
Carrying extra fuel is cheap insurance. |
I can see why the bean counters do these sums & come up with tangible figures that drive cost savings as they multiply what appears piddly stuff all per airframe across the whole fleet over a financial year & bingo numbers that makes a bean counter smile:-)
Trouble is to cut costs & lets face it every industry is cutting costs some by way of less employees or ceasing Ops (Ford in Geelong for Eg) there are only a few avenues for the bean counters to work with & that is the human element to the base costs of a product & a more efficient use of that product. The human element is malleable by way of work place/product efficiencies producing more for the same effort/wages cost. We are constantly seeing how the bean counters are trying to make the machine work more efficiently. Now right or wrong there is merit in some of this (as if there wasn't then no one would have a job) but as we all are saying here at what cost? Changing CI for Eg in a planes FMGC might be all well & good on paper for the bean counters but one storm, some holding by ATC (BN perfect Eg) a diversion as is the core subject here in this thread or even a request for speeding up can erase what small saving was going to be gained for that particular flight in the first place. The single biggest problem to all this is safety & that as we known comes at a cost. Commercialism the very reason why we have transport planes in the first place is the overriding factor & the exact reason as to why these couple of A/C ended up in this situation is all based on cost. The balance to safety & commercialism if bloody tenuous that's for sure! To protect the man within the machine first the man has to be placed ahead of the machine, that won't happen as man costs, the machine produces money. Solution?...............fill in the spaces knock yourselves out but for a start stupidly cheap airfares is where it all started I believe! Wmk2 |
Or would suggest that Qantas just hasn't dobbed theirselves into the ATSB yet. Carrying extra fuel is cheap insurance Some decent infrastructure may be the only solution to this sort of problem |
Interesting topic
devils advocate on fuel 40kg ($40) extra burn on every flight times 500/ day ( no idea how many VA or QF do) time 365 = over 7 million dollars in extra fuel burn per year. But if you need it you carry it! |
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