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JammedStab
22nd Mar 2015, 18:44
Courtesy of Aviation Week

Engineering Judgment Key In 757 Forced Landing In Antarctica

Foresight and cool-headed teamwork by pilots of a Royal New Zealand Air Force Boeing 757-200 likely saved their aircraft, 11 fellow crewmembers and 117 passengers—including scientists from New Zealand and the U.S. and New Zealand’s minister of foreign affairs—from a crash-landing in near-zero-visibility conditions at a remote science outpost at the bottom of the Earth in October 2013.

The account is detailed in a New Zealand Transport Accident Investigation Commission (TAIC) “landing below published minima” report, which is accompanied by recommendations aimed at preventing similar occurrences in the future.

The Royal New Zealand Air Force (RNZAF) “40 Sqdn.” operates the 757 and Lockheed C-130 Hercules out of its base in Auckland, providing regular flights between Christchurch and the McMurdo research station in Antarctica as part of a joint logistics pool with the U.S. The arrangement started in 1965, and the 757 joined the fleet in 2010. Whereas the C-130 has several landing options at McMurdo, some requiring skis, the 757 at that time of the season was limited to operations at Pegasus Field and its single 10,000 X 150 ft. runway on permanent ice. The incident flight was the second of three 757 flights scheduled to provide support for the early summer season at McMurdo, with three further flights planned at the season’s end in February and March.

Due to the length of the flight—about 4 hr., 45 min.—procedures called for computing two “point-of-safe-return” thresholds, a worst-case scenario where the aircraft with both engines operating must fly low due to a pressurization problem (PSR-2d), and a less conservative case using both engines at altitude (PSR-altitude). The crew, a captain/instructor, captain-in-training, co-pilot and second captain, decided to use the more conservative PSR-2d, which would occur 2 hr., 47 min. into the planned 4-hr., 40-min. flight. Weather would be a key element in that decision, with the crew receiving real-time and forecast weather over satellite links provided by the U.S. Navy’s Space and Naval Warfare Systems Command’s Office of Polar Programs (SOPP) based in Charleston, South Carolina, and at McMurdo.

The flight had already been delayed two days by weather, and a 7:00 a.m. briefing on Oct. 7 called for “presence of mist with some cloud on the ground,” but with the promise of clearing “during the morning.”

After more weather briefings, the aircraft departed Christchurch at 9:57 a.m. Nearing the PSR-2d time, the crew was becoming increasingly concerned about fog in the vicinity of Pegasus based on updated weather reports. However, the SOPP assured the pilots the fog was “in the distance” and later that it was on the field but was “shallow” and moving away. They were told to expect a visual arrival. The aircraft passed the PSR-2d and, 41 min. later, the PSR-altitude, with forecasters noting that fog was several miles or more away from the airfield.

Weather updates received at 1:45 p.m.—past the point of no return—showed “cloud on ground” with a broken layer of clouds at 300 ft., below the 360-ft. minimum descent altitude (MDA) for the instrument approach to Runway 33. A satellite phone call to the SOPP verified that fog had now formed over the airport.

Committed to a landing attempt, the pilots strategized the arrival, selecting a GPS approach but setting the MDA at 410 ft., due to an unusable section at the beginning of the runway, and asking the airport to turn the approach and runway lights to the brightest setting. The aircraft descended into the cloud bank at 700 ft. altitude and continued down to the MDA, but with no visual sign of the runway, a condition that requires a go-around. The crew climbed to clear air 5,000 ft. and entered a holding pattern for 2 hr. as they waited for conditions to improve, as forecasted. The weather, however, continued to deteriorate, so the pilots set up a second approach, reducing the MDA to 100 ft., an altitude they felt would still provide a safety margin above obstacles around the runway. Passengers and remaining crew were briefed on the situation and seated near the various emergency exits.

At the new MDA of 100 ft. on the second approach, the pilots again did not see the ground; but, during the go-around that followed, a second captain positioned in the observer’s seat in the cockpit saw “several markers and some lights” about 50 ft. to the right of the aircraft. The crew decided that what he had seen were the runway centerline approach lights, meaning the 757 had been about 50 ft. left of centerline on the approach.

The information was somehow familiar—the captain and two other pilots had flown the first flight of the season to Runway 33 in good weather on Oct. 3 and had calibrated the GPS approach and taken pictures. At that time, they had determined that the runway centerline was offset to the right of the inbound course by about 50 ft., a likely consequence of the ice shelf moving since the most recent calibration the previous season. The GPS approach was considered valid, as a new calibration had not yet been conducted.

Using that knowledge and confirming what the second captain had seen against photos that the captain-in-training had taken of the approach on Oct. 3, the crew set up another GPS approach offset to the right by 50 ft. When reaching 110 ft., the co-pilot saw the approach lights and the captain was able to confirm the aircraft was lined up, turn off the autopilot and flare for landing. The 757 stopped with 4,000 ft. of runway remaining and 3,000 kg of fuel, enough for one more approach. The fog cleared 90 min. later.

The TAIC says that, given the weather information and reassurances from the SOPP, the crew was “justified” in continuing beyond the two PSRs and was then left with “no other option” than to land in Antarctica “regardless” of the weather. “The fundamental safety issue arising from this incident was not the decision by the crew to pass the PSR and descend the aeroplane below the MDA in order to make a successful landing,” the TAIC states. “The issue and question is why the aeroplane ended up in that position when the crew had followed standard operating procedures.”

In response, the RNZAF changed its procedures, lowering its cloud base minimums for the 757 flights and adding a requirement that reported or forecast visible moisture below the minimums must be considered, with crews “ultimately being satisfied that the drivers that may cause these conditions to worsen will not be present for arrival.” The 757 procedures were also modified to require that GPS approaches be validated on the first missions of the season.

Engineering Judgment Key In 757 Forced Landing In Antarctica | Commercial Aviation content from Aviation Week (http://aviationweek.com/commercial-aviation/engineering-judgment-key-757-forced-landing-antarctica)

atakacs
22nd Mar 2015, 19:33
Interesting read.
Just wondering is there anything (short of cost of course) percluding the setup of a full cat III setup there? Given the absolute lack of diversion option it might still be a sensible investment

calypso
22nd Mar 2015, 20:25
Continuing towards an isolated airfield with with shallow fog in the vecinity? it might meet military rules of engagement but it seems very sporty for a 757 with over 100 people on board. Minimums are just that, minimums. Nothing precludes the commander to have a quiet word with himself. If you are going to proceed without a plan B your plan A better be absolutely rock solid. It does not take many years of flying to know that fog can be unpredictable, it may appear sooner or it may linger longer; any mention of it should give an experienced crew pause for thought. The fact that they complied with minimum legal requirements, while a good reason to change those requirements, seems a poor excuse to get yourself into such a mess.

I would have been less than pleased if I had been a passenger.

Sop_Monkey
22nd Mar 2015, 20:27
Same thought crossed my mind reading the above. Any ILS has to be better than a non precision approach.

juniour jetset
22nd Mar 2015, 20:59
agreed calypso - this incident should be seen as a shot across the bow for all organisastions making flights down there

the incident report smelt of a 50/50 bet in my mind, which the passengers should never have been put in

Arfur Dent
22nd Mar 2015, 21:01
"Passengers and remaining crew were briefed about the situation and seated near the emergency exits".
Why? Presumably in case the aircrew allegedly in charge of this mess crashed into the ice at 150 knots or so!!!
You'd think all this time after Mt Erebus, Antipodean operators would show a bit more respect for Antarctica.
Changed their SOP's?? I should CoCo!!!:=

TDK mk2
22nd Mar 2015, 21:03
If the investigating authority found the crews actions in proceeding beyond the point where they had any other option but to land in Antarctica justified, how is it that people on here still think they know better?? Do we have a bona fide sky god in our midst, in Mr Calypso?

ASRAAM
22nd Mar 2015, 21:04
To me the error would appear to have been made when the aircraft was purchased.

If one of its tasks is to support a remote airfield nearly 5 hours away with no aids and unpredictable wx the chosen aircraft should be able to carry return fuel ( or be capable of AAR if the Aussies are prepared to lend tanker support).

Lookleft
22nd Mar 2015, 21:11
A very similar incident to this one that occurred to a Virgin and Qantas 737 in Australia.

Investigation: AO-2013-100 - Weather related operational event involving B737s VH-YIR and VH-VYK at Mildura Airport, Victoria on 18 June 2013 (http://www.atsb.gov.au/publications/investigation_reports/2013/aair/ao-2013-100.aspx)

The Virgin crew did something very similar in coming as low as possible to check how far offset from the centreline they were then conducting another approach and flying it to the runway.

CargoOne
22nd Mar 2015, 21:12
I think there are certain difficulties in accepting widebodies down there. Everything else dont have 13 hours endurance. C17 can do it but there is a cost attached

Ps actually I know there are both 319ACJ and BBJ been utilized but I doubt they have enough endurance with reasonable payload to avoid point of no return if you count in 2 landing approach attemps in

calypso
22nd Mar 2015, 21:20
If proposing that one should avoid taking risky bets with the weather in an isolated aerodrome leading to placing your aircraft and passengers in danger unnecessarily makes me a Sky God in your mind then so be it. You might find there are plenty of us around.

The investigating authority might have further information not available to us or might be under other pressures or vested interests. We can only comment here on the information that has been published.

atakacs
22nd Mar 2015, 22:40
Well calibration should be obviously performed in a much regular / intensive basis than other places but I still believe it would be an option (I'm pretty sure ice is not moving that fast :))

currawong
22nd Mar 2015, 23:25
Pilots flying and making decisions.

The Australian regulator will be having some sort of fit reading this.:rolleyes:

Fortunately, this was none of their business.

skyhighfallguy
22nd Mar 2015, 23:52
I think, that in the circumstances, the crew did just fine.


Do you want a sure thing? Don't go to the antarctic .

Its not like they were flying into a 5000' strip in the middle of chicago and breaking minimums.

IF they landed, long, it would have worked out.

Lights in sight , they landed. Sure, they busted minimums.

The only questionable thing was the guy who kept saying the fog would go away.

Sop_Monkey
23rd Mar 2015, 00:22
What about the installation of a good old fashioned PAR. These can be more or less portable. Designed for the military, so ideal for that location and if the operator is good, and the handling pilot is "good" at basic IF the aircraft could be landed on the center line in virtually zero vis. If a/c are proceeding past their PNR's the situation is critical by anyone's estimation.

I've done PAR's with talk down by ex Eastern block radar operators and they were excellent. Obviously had a lot of practice at talking down fighters with next to no fuel.

Bob Viking
23rd Mar 2015, 02:15
What strikes me when reading this is that to pass comment you need to be familiar with the locale.
For example, as a Brit I came to Canada thinking I'd experienced flying in winter weather before. I quickly realised that our Canuck friends are slightly more au fait with it than we are in Britain. It would be easy, as a Brit pilot, to read a report describing a similar incident in Canada and wonder why the hell they were operating in such conditions in the way they often do.
It is too easy to apply our own experiences to a situation and pass judgment based on them but I'm willing to bet the crew in this incident were not idiots.
Whilst we may look at this report and think we would have done things differently it is largely immaterial unless you are an RNZAF 757 Captain who has routinely operated into Antarctica.
I could be way wide of the mark of course and I'm sure many will disagree but I think it is too easy to sit in the comfort of an armchair and criticise when you probably don't have the full picture.
BV

framer
23rd Mar 2015, 02:23
but with the promise of clearing “during the morning.

the SOPP assured the pilots the fog was “in the distance” and later that it was on the field but was “shallow” and moving away. They were told to expect a visual arrival.

It seems to me that once the aircraft had gone past the PNR the situation was well handled. TAIC identified SOP's as the reason that the aircraft ended up in that situation as the main issue but I think it is more complicated than that. For example, introducing more restrictive SOP's around continuing past PNR does what?.....it guides the Captain in his/her decision making. Decision making? Now we're getting to the crux of it......
A long hard look at how the RNZAF provides it's pilots with the information/experience, processes to make important decisions may well conclude with the finding that the RNZAF is doing these things to the highest standard. Equally, it may well find one or two areas where the provision of further support/training could improve the product (RNZAF pilot). Just as important as the decision making training is the cultural environment in which the important decisions are made. The RNZAF failed dismally to create a positive safety culture on 3 Sqn prior to the ANZAC day 2010 Iroquois crash and admitted as much in the aftermath. I imagine they have since improved the overall safety culture and have created an environment where conservative decisions are met with respect and acceptance and analysed properly rather than an environment where they are automatically tossed in the " man-up" category.
Assuming that they have moved with the times and are actively managing their own culture from the top down, a good hard look at the reasons why the 'decision making error' of continuing past PNR was made could well result in making an excellent Airforce even better.

ExAdvert
23rd Mar 2015, 06:19
Bob Viking is spot on. For 99% of the people this forum, their comments will be pure speculation..... well-intentioned speculation no doubt but speculation nonetheless.

Unless you've flown in the Antarctic. Unless you're familiar with the CONOPS down there. Unless you know McMurdo & Pegasus Field. Unless you know how fickle the wx can be. Unless you know how poor the forecasts usually are (it's a very big place with very sparse data). Unless you have intimate knowledge of the RNZAF's B757 SOPs & how their PNR/ PSR procedures cater for the inevitably sketchy wx forecasts on the ice..... I could go on.

Feel free to ask questions but perhaps think twice before passing sanctimonious judgement on the decisions & actions of a professional crew whose working environment you probably know very little about.

FleurDeLys
23rd Mar 2015, 07:19
The most extraordinary feature is the difference between the local forecast /obs while the a/c was en route, and the experience in the cockpit.

A wittier man than I might be tempted to enquire whether the ground observer/forecaster was due to leave on the 757's return leg?!

Tourist
23rd Mar 2015, 07:54
It's Antarctica.

It's not a commercial airline.

Antarctica requires greater risk appetite than some city in Europe.

It is perfectly acceptable to take risks in the interests of Science/development.

JanetFlight
23rd Mar 2015, 08:25
Aviation Reports (http://www.taic.org.nz/ReportsandSafetyRecs/AviationReports/tabid/78/ctl/Detail/mid/482/InvNumber/2013-009/Page/0/language/en-US/Default.aspx?SkinSrc=)[G]skins/taicAviation/skin_aviation

You can download the full Incident Report here...however its curious the fact its a report made by a civil organization to a military aircraft??

NigelOnDraft
23rd Mar 2015, 08:59
Hardly worth commenting unless you read the report itself, at which point it all seems quite reasonable.

The report hints, but does not detail, the Plans B, C... available if they had not got in off the last approach. There were options even "runways" available - not ideal but I suspect there was a reason they made the last approach to land with 3T.

NoD

JammedStab
23rd Mar 2015, 10:54
With no alternate and only a non-precision approach, it seems that the only smart policy would be to not continue past the PNR unless it is a beautiful clear day. It appears that the temp and dew point spread were not far apart according to the weather reports.

In my opinion, deciding to hold for two hours when the weather has already started coming down and was now below minimums was not a good idea. Their decision to hold was based on an improving forecast but the forecasts for the day were already proven to be useless. They are very lucky that it didn't get really foggy. Actually, it did as it went from 1200m vis down to 200m vis in that time period. Any worse and they never would have made it in.

There is a time to play by the regulations and a time to bust them as was eventually done here but it really should have been done earlier when the ceiling was still 300' with 1200m vis with consistently deteriorating weather, daytime conditions in snow country which makes airport lighting almost useless and no alternate. It would have been fairly easy do get in two hours earlier.

Arfur Dent
23rd Mar 2015, 12:13
I can't believe what I'm reading.
"It's perfectly acceptable to take risks in the name of Science/development". NO IT ISN'T!!
There is only one way this will end and seating (presumably blissfully ignorant) passengers near Emergency exits is pointless and ridiculous.
As somebody just said - do all this on a Gin clear day with a good forecast or TURN Back! What on earth is the PNR for if you don't "R" when the weather is awful and getting worse???
Somebody needs to get a grip here.:mad:

Heathrow Harry
23rd Mar 2015, 13:06
This is equivaent to a military flight

everyone on board knows the risks of going to the Great White South, they know about Points of No Return, white-out and useless weather forecasts

They know about "Impact on Erebus"

It is a judgement you make

Agreed it would be criminal for a flight with the average SLF but for informed adults (and that includes tourists) it's what you risk to ge there. No one is forced to go

alfred_the_great
23rd Mar 2015, 16:27
I can't believe what I'm reading.
"It's perfectly acceptable to take risks in the name of Science/development". NO IT ISN'T!!
There is only one way this will end and seating (presumably blissfully ignorant) passengers near Emergency exits is pointless and ridiculous.
As somebody just said - do all this on a Gin clear day with a good forecast or TURN Back! What on earth is the PNR for if you don't "R" when the weather is awful and getting worse???
Somebody needs to get a grip here.

Oh dear lord, really? Perhaps the easy solution would be not to fly.

Herod
23rd Mar 2015, 17:33
Surely this incident is a prime example of why we still need two human brains at the pointy end. Classic example of it all going t*ts-up, and the humans make the sensible decision and save the day.

melmothtw
23rd Mar 2015, 17:46
Classic example of it all going t*ts-up, and the humans make the sensible decision and save the day.

Whereas this report into the Voyager 'camera on the flight deck' incident shows the exact opposite - https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/414371/20150317_-_Voyager_ZZ333_SI_Report_Part_1.5_-_1.6_Ex_Pub.pdf

"Frankly, without the excellent technology of the Airbus A330 flight control laws, the outcome could have been very different, with the realistic potential for the loss of the aircraft and 198 of our people."

NigelOnDraft
23rd Mar 2015, 17:51
and seating (presumably blissfully ignorant) passengers near Emergency exits is pointless and ridiculous.I can think of some very good reasons to do this after reading the report :ok:

NoD

Pontius Navigator
23rd Mar 2015, 18:07
Risk is only acceptable if there is sufficient reward.

What was the urgency for this flight?

NutLoose
23rd Mar 2015, 18:25
Incidentally how it got its name, another amazing landing

http://chefbillmorris.B l o g s p ot.fr/2011/12/pegasus-plane-crash.html

http://www.messynessychic.com/2014/02/19/abandoned-in-antarctica-the-1970s-airplane-buried-in-snow/

Must be a pig of a place to get fuel supplies too.

Onceapilot
23rd Mar 2015, 20:19
Hmmmmm, an interesting report. Well done the crew!
Having operated widebody pax in difficult wx and similar forecasting situations, it is still difficult to be objective without having their actual SOP and orders. However, I have two observations: without a wx div/any div, you will always be committed to destination after PNR. Also, surely a CAT3 ILS/MLS would be immune to movement of the airfield and should be mandatory for no div pax (outside pure mil ops)?

OAP

ShotOne
23rd Mar 2015, 23:09
Very good point OAP; surely the GPS minima is based on a precise track and becomes meaningless when placed on a moving ice cap. And While I'd heartily agree with the "well done" for the approach, but perhaps not for the en-route decision making.

As for plans B and C, er, what were they, just out of interest?

NigelOnDraft
23rd Mar 2015, 23:13
As for plans B and C, er, what were they, just out of interest?Not stated as such, but if you read the report, you might make a guess ;)

but perhaps not for the en-route decision makingI'd need to re-read it, but AFAIK the decision making was exactly iaw the SOPs, which in turn were based on extensive experience. This incident added to that experience "database", and resulted in the SOPs being tweaked. The report went out of it's way to praise the crew throughout IIRC?

NoD

ShotOne
24th Mar 2015, 09:31
With 3000 kg fuel over a fogged out icecap and nowhere to land for thousands of miles, those plans B and C would have to be exceptionally cunning, NoD!

I'm intrigued by some of the detail here; the decision to use an earlier PNR based on pressurisation failure forced them to commit to land or crash in Antarctica 45 minutes earlier in worsening weather. Yet this is described as "conservative".

Given the critical importance of weather reports, the phraseology strikes one as rather "of the cuff" ... like "cloud on the ground" -as if someone desperately wanted to avoid using the word "fog"! And why no mention anywhere of temperature versus dew point?

NigelOnDraft
24th Mar 2015, 10:24
...and nowhere to land for thousands of miles, those plans B and C would have to be exceptionally cunning, NoD!You clearly have not read the report ;)

I would agree there was no suitable diversion in conventional terms. I would disagree there was "nowhere to land in extremis", one option is mentioned in the risk profile.

NoD

Onceapilot
24th Mar 2015, 10:25
Something that could be highlighted is that, despite the best professional capabilities of the met man, the weather can be so unreliable in some locations that a current METAR is the only accurate info. If you read the report, it says that the forecasting mainly relied on 4 general wind directions.:cool:
In worldwide aviation we can get conditioned to give a very high reliability factor to all forecast weather. Unfortunately, there is no quality index for forecasting locations that I am aware of.:uhoh:

OAP

Tourist
24th Mar 2015, 12:18
I think some on here have a lack of understanding about the operating circumstances of Antarctica.

To give some idea of context.

There are aircraft down there carrying passengers which land IMC on flat areas of snow in IMC/whiteout.

They set a hand flown gentle rate of descent in IMC and continue down until the aircraft stops going down and then they stop.

No ILS, No runway, No CAT3B, no minima, no autopilot, single pilot and not so much as an NDB.

That is SOP, not an emergency.

A 757 I will grant you had more pax, but in the grand scheme of things, a planned descent below minima is not that big a deal.

Antarctica is not normal ops. If you get ill down there you may die because of lack of doctors too.

Without risk nothing new has ever been achieved. If the wussy on here had been in charge man would have never have left the trees.

Heathrow Harry
24th Mar 2015, 12:21
anyone going south knows the weather forecasts are.... aspirational

You go and most of the time it works out ok - occasionaly you have to turn back - and very occasionaly it requires the sort of effort these guys put in

as has been said - that's what it takes to operate down there - this isn't running a 737 from Stansted to Ibiza

ShotOne
24th Mar 2015, 16:16
It's all very well to argue" man would never have left the trees" but another view is that if we just accepted everything's fine, aviation would never have developed to its current pinnacle. Yes, tourist, aircraft land on skis in zero vis. But what might work at 50 kts in a twin otter won't in a 757 ! Fwiw, I believe Antarctic research IS worth incurring risk but a few issues stand out; given its crucial importance, weather information seemed to be passed in a surprisingly casual and conversational way. Were visibility, temp and dew point ever passed? If so they weren't mentioned here. And why was the 50' position shift only discovered by the crew? Surely this could have been checked by anyone with a £50 handheld GPS, or even an iPhone, rather than a low flyby in an airliner full of passengers?

Tourist
24th Mar 2015, 17:14
Pinnacles in history can only be judged with the benefit of hindsight. I personally believe we will look back with horror at latter years of manned flight.

That said I agree with what you say. If on the previous flight it was noticed that the runway had shifted, there should have been a proceedure in place to update.

The rest of the armchair wisdom from many posters on here is disrespectful to a crew who, from what I read produced a textbook solution to a tricky situation.

GlobalNav
25th Mar 2015, 17:40
The airmanship demonstrated on this flight is quite outstanding. The flight crew's awareness and problem-solving was top-notch in my opinion. They followed procedures as far was they would take them, but adapted to the situation as the "fog of war" (in this case "fog of the Antarctic") required. I'd buy these guys a round any day. Cheers! :D

The on-board database likely had the coordinates for the desired approach, but the world (possibly the satellites) moved a bit. The crew took note and found a way to adjust. Not what we want for commercial passenger operations, but as many other alluded to, in this environment, CONOPs etc, precisely why we like professional, well-trained military pilots to deal with such contingencies.

KenV
25th Mar 2015, 20:49
Surely this could have been checked by anyone with a £50 handheld GPS, or even an iPhone, rather than a low flyby in an airliner full of passengers?

The above shows a rather large gap in understanding of approach calibration requirements. Clu4U, it cannot be done legally or properly with a "handheld GPS or iPhone". Using such equipment is far worse than not doing it at all.

If on the previous flight it was noticed that the runway had shifted, there should have been a proceedure in place to update.

Having a "procedure in place" and having the required certified equipment in place are two VERY different things. And without the latter, the former cannot be done. And the latter simply does not exist in Antarctica.

alfred_the_great
26th Mar 2015, 08:02
Or would take an aircraft to fly it in......

ShotOne
26th Mar 2015, 11:45
I'm not suggesting, Ken, a DIY recalibration of the RNAV approach, only monitoring whether the ice cap has shifted since the approach was created. This wouldn't require specialist equipment and I'm surprised it isn't done.

Ok465, I agree 50' is not an unreasonable RNPerror; that's why RNAV minima is higher than was used here! ...but ice cap shift would be on top of any RNP error. Its entirely your speculation which was responsible for the error observed by the crew. If we accept your view though, the crucial 50' could have been in a different direction after the crew had cool-headedly factored it in. Which merely emphasises that for all the undoubted skill of the crew, luck played a good part in this successful outcome.

JammedStab
28th Mar 2015, 16:51
Interesting that the weather forecast given to the crew prior to the PNR shows three hundred feet scattered layer yet this weather forecast is above the minimum requirement to continue.

Whoever made the rules about having a scattered layer below minimums as being acceptable made a bad decision. SCT can be 3/8 coverage. A slight bit more and it is a broken ceiling. Surely almost everyone on this forum has seen a low SCT layer become the ceiling.

I have done a missed approach because of a scattered layer below minimums. We did happen to make it in that time but we also had an alternate. I think a serious review is required in this operation in regards to weather.

Onceapilot
28th Mar 2015, 19:23
Jammed mate, some SOP recognise BKN as a cloudbase.

OAP

Heathrow Harry
29th Mar 2015, 10:22
I'm amazed people are still banging on about the weather and the forecast as if this was AMsterdam or SFO - its a single point in the middle of a continent with the worst weather in the world........


There are no rules down there

JammedStab
2nd Apr 2015, 14:41
There are no rules down there

Sure there are. But there are no alternates down there. Meaning.....very strict rules are a good idea so you don't get into a situation where you need to break the rules to survive.

KenV
2nd Apr 2015, 19:09
I'm not suggesting, Ken, a DIY recalibration of the RNAV approach only monitoring whether the ice cap has shifted since the approach was created. This wouldn't require specialist equipment and I'm surprised it isn't done.

Surprised? Why? Does "surprise" not reqiure one to assume that it is not done? In fact, scientists routinely measure ice cap movement as part of the research protocols using MUCH better equipment than iPhones and the like. But there is a world of difference between using such equipment for research and using it to update an aviation nav approach. And beyond that, a 50 ft error is within allowables for a non precision approach.

KenV
2nd Apr 2015, 19:16
...very strict rules are a good idea so you don't get into a situation where you need to break the rules to survive.


A "good idea" from the comfort of one's chair in front of a computer screen is likely a very lousy idea in the realities of antarctic aircraft operations.

From personal experience, many "good ideas" associated with aircraft operations from long and wide concrete runways are absolutely lousy ideas when used in carrier aviation. And often the other way around.

ShotOne
2nd Apr 2015, 22:01
"assume that it's not done..." Not my assumption, Ken. From the published account, whether or not any such measurement was made, it wasn't made available to the crew.

"a 50' error is within allowables.." You're getting your knickers in a twist, Ken; the RNP error you refer to (I agree 50' wouldnt be unreasonable)takes account of atmospheric and system error. But ice cap shift, if indeed there was any, would be IN ADDITION to this.

ChrisJ800
2nd Apr 2015, 23:07
I believe the Australian flights from Hobart to Antarctic using a A319 have enough fuel to land and return without refuellling, is this not the case with the NZ flights?

JammedStab
4th Apr 2015, 08:24
A "good idea" from the comfort of one's chair in front of a computer screen is likely a very lousy idea in the realities of antarctic aircraft operations.

From personal experience, many "good ideas" associated with aircraft operations from long and wide concrete runways are absolutely lousy ideas when used in carrier aviation. And often the other way around.

Actually, they would have been in comfy chairs in front of computer screens for their briefing. Same with the guys who made the rules. So it would have been a good idea to observe strict weather rules.

If by carrier aviation you mean for airlines, these rules I suggested are actually much more strict....and common sense.

300 feet scattered in the forecast, nearby fog bank. Minimums are 400 feet for the only approach, a non-precision approach on an ice strip with no alternate, likely whiteout if the weather craps out and likely ineffective lights(although dark fuel drums will be very good for daytime ops). Do you need to be in a comfy chair do decide if it is a good idea to depart in a big jet.

Or is this an absolutely lousy idea in your opinion?