A thumbnail, dipped in tar.
"And an answer came directed in a writing unexpected,
(And I think the same was written in a thumbnail dipped in tar)
'Twas his shearing mate who wrote it, and verbatim I will quote it:
"Clancy's gone to Queensland droving, and we don't know where he are."
This post is definitely not for the purist or the professional. However, I get asked, a lot, to explain the ‘fuss’ about fuel and ‘critical’ points along the James flight path. Operationally, the matter is not too complex – legally, when CASA get determined to prove a point, it’s a bloody nightmare. Putting aside the twisted Chambers logic and the ‘niceties’ of flight planning I shall endeavour to explain why most thinking pilots are calling bollocks’ on most of the CASA assumptions and ridiculing the Walker attempts to foist yet another flawed report on the ditching. Why Walker is determined to do this and why CASA is happy to assist is a question we cannot answer – yet. The ‘T’ documents and other supporting ‘paperwork’ read properly, with a time/date line analysis almost completely exonerate James; but more of that later. Lets take a layman’s quick guided tour through a practical examination of the flight, it may shed some light.
Fuel – a must have. There is a finite amount of fuel which may be loaded onto an aircraft and it is ‘heavy’. There is a finite amount of power which may be extracted from the engines. The eternal problem is one of aircraft weight, the amount of fuel needed to move that weight and the rate at which the fuel is consumed. Jet aircraft fuel consumption benefits from altitude; high is good; but, the engine power available must be equal to supporting the aircraft at its weight at the optimum altitude. This is why a ‘Stepped’ climb profile may be used; climb to 36,000 is acceptable, cruise for an hour, weight reduces and a climb to 38,000 may be possible; this reduces the overall fuel burn off and, has the effect of ‘making’ fuel, which may be used to calculate the ‘critical’ gateways along the route. It is standard operating practice, legal and safe to operate in this fashion – Qantas would hardly get a long haul flight completed if the crew were not skilled in managing the ‘weight/fuel/distance/ weather at destination equation.
But we need to consider the ‘en-route’ gateways. Release points if you will; each gateway is a decision point; crew are always aware of an approaching ‘gate’ they do the sums, weigh up the ‘ifs and buts’ and are prepared to make a decision at that gate. So lets place ourselves in cruise at 36, 000 feet (F360) half way between the departure aerodrome and our first gate; two items for consideration. Item one; the weight for a climb is calculated and the approximate time for initiating the climb is jotted down. Item two: action in the event of abnormal or emergency conditions arising This is a no brainer; each of the ‘standard’ scenarios is predetermined; the only variables are the wind, temperature and weather’ (which may not be exactly as forecast at the planning stage) which call for minor adjustments to the time at which the aircraft will arrive at the gateway and the actual amount of fuel available to meet the requirements. As we approach gate ‘A’ the calculations are complete; provided we do not have a failed engine; or, have not lost cabin pressure and the weather at the destination is still acceptable – there is no decision, other than to continue which needs to be made. Should any of the ‘critical’ elements change in a manner which affects the amount of fuel we have to use then the decision is simplicity itself. We divert to an alternate; this is pre planned, fuel is allocated to complete the diversion, the time taken to reach an alternate is known and – with a little luck – apart from the expense and inconvenience – all should be well. Thus, we proceed past our ‘gateways’ toward our destination; each gateway has it’s own ‘limitations’ and decision making prerequisites which influence that decision. We, finally, arrive at gateway ‘X’ and find that due to the wind conditions we have insufficient fuel to meet the requirements – we divert. Once past gate ‘X’ provided the destination weather remains acceptable we toddle along to the top of our descent; once we have passed gate ‘X’ there is no spare fuel to divert anywhere – there is fuel for the depressurised situation; for the engine fail situation; fuel to meet any holding requirements, fuel to complete at least one instrument approach; there is even enough fuel for a missed approach and a second whack at landing. But that’s all she wrote. Well, it is unless you happen to be operating under any other rule set bar the Australian ones; it is mandatory [FAA for e.g.] (and most sensible) to carry enough fuel to divert from the intended destination to an alternate airfield; with acceptable weather conditions.
It is a ramble, I know, but if we must dive into the Pel-Air debacle then it is important (IMO) that ‘muggles’ understand at least the basics. So lets look at the Pel-Air flight, from a practical standpoint.
If you grab a clean sheet of A4 the draw a line from top right to bottom left it will assist. Put a dot for Apia in the top right; a third of the way along the line put a dot for Fiji; two thirds the way a dot for Noumea and in the bottom left a dot for Norfolk Island.
James ‘radius of action’ was, on departure Apia somewhere about 180 miles past Norfolk Island, toward the mainland – assuming normal operations. The single engine ‘radius of action’ and the ‘depressurised’ radius are a good way down the line. The Point of No Return to Apia becomes academic and of no interest. Connect our flight path line to Fiji; there are two perfectly serviceable airports available there; ‘South abeam Fiji’ James could reset all his calculations; his critical gates would now be return to Fiji or divert the Noumea; he had plenty of fuel to do either until he passed the point where Noumea was the closest option. So far so good. Now, connect our flight path with Noumea; once again two suitable airports. South abeam Noumea James could reset his calculations; divert if things started to go wrong with the aircraft or, continue on toward Norfolk until he passed the point where a return to Noumea was ‘impractical’.
The only variable in all of this was the Norfolk Island weather. CASA insist that James should have based his decisions on the weather forecast provided – in flight. The problem is James never received an updated weather forecast until he was past the final, crucial decision gate. Had the 0739 or the 0803 conditions been relayed, before he was committed to Norfolk, a diversion was possible and mandatory. Lots of folk seem to be skipping past this crucial element. I have ‘done the numbers’ and agree with the Davies summary – with one exception. James was ‘fat’ for fuel all the way and dead set ‘legal’ until it was too late; even then, had the gods smiled, he may have ‘squeaked’ in, as many of us have, under the cloud base. Alas….
I do, most sincerely, apologise to the purists; but unless the muggles get at least a mud map of the core issues, to explain what we’re banging on about; then, the pony-pooh from ATSB and CASA is just going to accepted as correct – well it ain’t..
Phew; wish I’d never started this post; second coffee just became a mandatory requirement.
Toot toot.
"And an answer came directed in a writing unexpected,
(And I think the same was written in a thumbnail dipped in tar)
'Twas his shearing mate who wrote it, and verbatim I will quote it:
"Clancy's gone to Queensland droving, and we don't know where he are."
This post is definitely not for the purist or the professional. However, I get asked, a lot, to explain the ‘fuss’ about fuel and ‘critical’ points along the James flight path. Operationally, the matter is not too complex – legally, when CASA get determined to prove a point, it’s a bloody nightmare. Putting aside the twisted Chambers logic and the ‘niceties’ of flight planning I shall endeavour to explain why most thinking pilots are calling bollocks’ on most of the CASA assumptions and ridiculing the Walker attempts to foist yet another flawed report on the ditching. Why Walker is determined to do this and why CASA is happy to assist is a question we cannot answer – yet. The ‘T’ documents and other supporting ‘paperwork’ read properly, with a time/date line analysis almost completely exonerate James; but more of that later. Lets take a layman’s quick guided tour through a practical examination of the flight, it may shed some light.
Fuel – a must have. There is a finite amount of fuel which may be loaded onto an aircraft and it is ‘heavy’. There is a finite amount of power which may be extracted from the engines. The eternal problem is one of aircraft weight, the amount of fuel needed to move that weight and the rate at which the fuel is consumed. Jet aircraft fuel consumption benefits from altitude; high is good; but, the engine power available must be equal to supporting the aircraft at its weight at the optimum altitude. This is why a ‘Stepped’ climb profile may be used; climb to 36,000 is acceptable, cruise for an hour, weight reduces and a climb to 38,000 may be possible; this reduces the overall fuel burn off and, has the effect of ‘making’ fuel, which may be used to calculate the ‘critical’ gateways along the route. It is standard operating practice, legal and safe to operate in this fashion – Qantas would hardly get a long haul flight completed if the crew were not skilled in managing the ‘weight/fuel/distance/ weather at destination equation.
But we need to consider the ‘en-route’ gateways. Release points if you will; each gateway is a decision point; crew are always aware of an approaching ‘gate’ they do the sums, weigh up the ‘ifs and buts’ and are prepared to make a decision at that gate. So lets place ourselves in cruise at 36, 000 feet (F360) half way between the departure aerodrome and our first gate; two items for consideration. Item one; the weight for a climb is calculated and the approximate time for initiating the climb is jotted down. Item two: action in the event of abnormal or emergency conditions arising This is a no brainer; each of the ‘standard’ scenarios is predetermined; the only variables are the wind, temperature and weather’ (which may not be exactly as forecast at the planning stage) which call for minor adjustments to the time at which the aircraft will arrive at the gateway and the actual amount of fuel available to meet the requirements. As we approach gate ‘A’ the calculations are complete; provided we do not have a failed engine; or, have not lost cabin pressure and the weather at the destination is still acceptable – there is no decision, other than to continue which needs to be made. Should any of the ‘critical’ elements change in a manner which affects the amount of fuel we have to use then the decision is simplicity itself. We divert to an alternate; this is pre planned, fuel is allocated to complete the diversion, the time taken to reach an alternate is known and – with a little luck – apart from the expense and inconvenience – all should be well. Thus, we proceed past our ‘gateways’ toward our destination; each gateway has it’s own ‘limitations’ and decision making prerequisites which influence that decision. We, finally, arrive at gateway ‘X’ and find that due to the wind conditions we have insufficient fuel to meet the requirements – we divert. Once past gate ‘X’ provided the destination weather remains acceptable we toddle along to the top of our descent; once we have passed gate ‘X’ there is no spare fuel to divert anywhere – there is fuel for the depressurised situation; for the engine fail situation; fuel to meet any holding requirements, fuel to complete at least one instrument approach; there is even enough fuel for a missed approach and a second whack at landing. But that’s all she wrote. Well, it is unless you happen to be operating under any other rule set bar the Australian ones; it is mandatory [FAA for e.g.] (and most sensible) to carry enough fuel to divert from the intended destination to an alternate airfield; with acceptable weather conditions.
It is a ramble, I know, but if we must dive into the Pel-Air debacle then it is important (IMO) that ‘muggles’ understand at least the basics. So lets look at the Pel-Air flight, from a practical standpoint.
If you grab a clean sheet of A4 the draw a line from top right to bottom left it will assist. Put a dot for Apia in the top right; a third of the way along the line put a dot for Fiji; two thirds the way a dot for Noumea and in the bottom left a dot for Norfolk Island.
James ‘radius of action’ was, on departure Apia somewhere about 180 miles past Norfolk Island, toward the mainland – assuming normal operations. The single engine ‘radius of action’ and the ‘depressurised’ radius are a good way down the line. The Point of No Return to Apia becomes academic and of no interest. Connect our flight path line to Fiji; there are two perfectly serviceable airports available there; ‘South abeam Fiji’ James could reset all his calculations; his critical gates would now be return to Fiji or divert the Noumea; he had plenty of fuel to do either until he passed the point where Noumea was the closest option. So far so good. Now, connect our flight path with Noumea; once again two suitable airports. South abeam Noumea James could reset his calculations; divert if things started to go wrong with the aircraft or, continue on toward Norfolk until he passed the point where a return to Noumea was ‘impractical’.
The only variable in all of this was the Norfolk Island weather. CASA insist that James should have based his decisions on the weather forecast provided – in flight. The problem is James never received an updated weather forecast until he was past the final, crucial decision gate. Had the 0739 or the 0803 conditions been relayed, before he was committed to Norfolk, a diversion was possible and mandatory. Lots of folk seem to be skipping past this crucial element. I have ‘done the numbers’ and agree with the Davies summary – with one exception. James was ‘fat’ for fuel all the way and dead set ‘legal’ until it was too late; even then, had the gods smiled, he may have ‘squeaked’ in, as many of us have, under the cloud base. Alas….
I do, most sincerely, apologise to the purists; but unless the muggles get at least a mud map of the core issues, to explain what we’re banging on about; then, the pony-pooh from ATSB and CASA is just going to accepted as correct – well it ain’t..
Phew; wish I’d never started this post; second coffee just became a mandatory requirement.
Toot toot.