[Peetwo]

Willow brings up PelAir ditching at ISASI presentation - WTD?? 

Reference:

Similar occurrences to that at Mildura in June 2013

A further review of the ATSB occurrence database identified five occurrences that had happened since 1999 and were similar to this occurrence. These occurrences were investigated by the ATSB  website and are detailed below.

ATSB investigation 199904029

ATSB investigation 200401270

ATSB investigation 200605473

ATSB investigation AO-2012-073

ATSB investigation AO-2015-067

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..In order to better quantify the residual risk, specifically the likelihood of unforecast weather deterioration, the ATSB is examining the reliability of aerodrome forecasts as part of research investigation AR-2013-200 Reliability of aviation weather forecasts. This research investigation will initially examine the reliability of the aerodrome forecasts for Mildura and Adelaide Airports, before expanding to cover other major Australian airports.

With the release of the ATSB AO-2013-100 (Mildura fog duck-up above) I was critical that in the 'related occurrences' section there was no mention of the VH-NGA ditching; nor was there mention of the previous unforecast weather related incidents that led to the ATSB issuing safety recommendation R20000040 on 22 February 2000...  

(P2 comment: As a 'passing strange' coincidence I have also now discovered that all the listed un-forecast wx related occurrences, including the Norfolk serious incidents/accident, have mysteriously not been listed/recorded on the ICAO (ADREP & ECCAIRS) iSTAR database.)

I was also critical that in the first David Wilson - AR-2013-200 - report that again the Norfolk incidents and ditching had seemingly been glossed over yet again...

However I am pleased to inform people that I can actually retract some of my previous criticisms...

This is because 2 weeks ago Willow made a presentation to the ISASI 2017 annual seminar (see HERE, day 2 between 1:30-2:30pm), which included much data related to unforecast wx at remote islands plus a reference to the VH-NGA ditching: Effect of ICAO Type Aerodrome Weather Forecasts on Aircraft Operations 

Comparison between remote islands and mainland airports

This algorithm was used by the ATSB to support an investigation of a serious weather-related incident at a remote Australian island. Specific hypotheses were put forward regarding the reliability of remote island forecasting, and the analysis conducted allowed definitive conclusions to be drawn regarding the relative reliability of these forecasts from the perspective of the historical likelihood of unforecast weather conditions below the landing minima.

        
This would seem to indicate that Willow's 'algorithm' will be featuring in the upcoming re-investigation final report into the ditching of VH-NGA...

So does this mean the ATSB finally acknowledge the very real parallel causal factors between the Mildura fog duck-up and the PelAir cover-up?

Well apparently not as it is rumoured that in the title of the 500+ page VH-NGA re-investigation final report, 'fuel management' is mentioned but not a serious weather-related incident (ditching).

 However this does not mean that the BRB can't examine in detail the (IMO) striking parallels related to the unforecast wx Swiss cheese hole...

Reference Willow's ISASI presentation:

Methods

The results presented required the development of a computer program (the algorithm). Full details are available on the ATSB’s website (www.atsb.gov.au) under investigation AR-2013-200.

The objective of the algorithm was to help calculate the probability of using the weather forecast system as it affects pilots, and number of expected aircraft arrivals during selected weather conditions. It uses actual historical weather forecasts (TAFs and TTFs) compared to reported observations (METARs and SPECIs) as they would be used by pilots. It also can examine what would have happened if a different type of forecast was used or the forecast was retrieved later in flight.

        
Now a relevant reference from AO-2013-100:

Use of weather observations for decision making

The flight crews of Velocity 1384 and Qantas 735 reported assessing the Mildura weather prior to diverting from Adelaide Airport. Both reported considering the observation reports that were current at the time as a more reliable indicator of the weather at Mildura Airport than the relevant forecast. The captain of Qantas 735 reported feeling that the observation reports were more reliable given the inaccuracy of the forecast at Adelaide.

The crew of Velocity 1384 reported using the observation reports to confirm their understanding of Mildura’s suitability as an alternate destination.

The ATSB asked CASA for a ruling on the use of observations in-flight. CASA responded that a pilot is able to use a valid forecast and observation information. They also cautioned that observations should only be used if the arrival time was proximal to the observation and, if the forecast indicated conditions below minima, the forecast would have precedence over observations. That is, crews must carry sufficient fuel to meet the forecast requirements affecting a destination, even if the observations at that location indicate that the weather is suitable for an arrival.

While the crew of Qantas 735 reported considering the implications of the TEMPO on the 0158 Mildura TAF, and calculated that they had sufficient fuel to meet this requirement, the crew of Velocity 1384 did not complete that consideration. The FO of Velocity 1384 raised the TEMPO as an issue with the captain; however, at that time the captain’s attention was on another matter and the TEMPO was not discussed. As such, when the crew of Velocity 1384 initiated the diversion to Mildura Airport, they had not confirmed sufficient fuel to meet the TEMPO requirement.

Irrespective, the extent and duration of the deterioration meant that even meeting the TEMPO fuel requirement, this would not have provided sufficient fuel to hold until the fog and low cloud at Mildura cleared sufficiently. Unless early consideration was given to a return to Adelaide Airport for an emergency autoland approach, a landing below minima at Mildura Airport was the only option at Mildura Airport.

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Mildura Airport

The 0358 amended TAF for Mildura that morning forecast light winds and scattered cloud at 3,000 ft and broken cloud at 6,000 ft. The TAF also included TEMPO periods between 0500 and 1000 in which the cloud base was forecast to reduce to 600 ft AGL.

A new routine TAF was issued for Mildura at 0902 that was valid from 1000. This TAF forecasted visibility in excess of 10 km and scattered cloud at 3,000 and 5,000 ft. No significant weather was listed on the TAF and no indication of low cloud or fog was given. Neither crew were aware of this TAF nor would they have been able to use this forecast in support of their decision to divert. This was because the Aeronautical Information Publication (AIP) Australia stated that a TAF that is valid for 30 minutes prior to the arrival must be used for flight planning purposes. As such, it could not be used for arrivals at Mildura prior to 1000.

A further amended TAF was issued for Mildura at 0952 and covered the period 1000–2200. This TAF forecasted a visibility of 3,000 m in mist, with scattered cloud at 300 ft AGL and broken at 4,000 ft AGL. In addition there was a 30 per cent probability of 500 m visibility in fog and broken cloud at 200 ft AGL between 1000 and 1200.

Next a reference from the once hidden now infamous CASA parallel investigation report CAIR 09/3:

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Now referencing Fig.2 &  original VH-NGA final report:

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& finally the part that highlights the (apparently) completely glossed over 'fact' and elephant in the room related to the PelAir causal chain, reference page 16 of the original VH-NGA final report:

An amended Norfolk Island TAF that was valid for the aircraft’s ETA was issued by the Australian BoM at 0803. In that TAF, the visibility was forecast to be 10 km or more, with Broken cloud at 1,000 ft above the ARP. Those conditions indicated that the weather would be below the alternate minima for Norfolk Island at the aircraft’s ETA, but above the landing minima. The flight crew were not advised, and were not required by any international agreement to be advised, of the amended forecast and they did not request an updated forecast for Norfolk Island during the flight.

  
So on one hand we had two crew that were (nearly) fully aware that their alternate airport had a TAF operational requirement (60 minutes TEMPO YMIA), but on the other hand we had a crew who had no idea that an amended TAF had been issued which automatically placed a operational (alternate) requirement on the conduct of the rest of the flight...

MTF...P2

Ps It should be remembered that auto wx observations do not place a legal operational requirement on a flight crew...