Air Safety, Weather or Not!

Early the next morning, and feeling refreshed after an early night, David telephoned Bankstown Briefing to obtain weather information so that he could complete his flight plan whilst he had his breakfast.

He explained that he was calling from West Wyalong and was planning a VFR flight to Bankstown with an ETD of 2200. It was now 6. 00am and while he normally hated early morning starts, when ii came to flying, he would get up at any hour. The briefer, who had been up even earlier than David, asked him to stand by while he shuffled through the latest information available. When he came back on the telephone, he was armed with a formidable array of data. David couldn’t remember it all, but he did take notes of the important bits that would influence the conduct of his flight. It included the following:

At time 1BOOZ, there was a trough located between Dubbo an<;i Swan Hill moving east at 25 knots. Winds east of the trough were generally from the northwest, at 5000′ 310 degrees 30 knots, above 7000′ 340 degrees 2Q knots. West of the trough, they were more north-easterly, to 5000′ 020 degrees 20 knots above 7000′ 030 degrees 30 knots. Cloud east of the trough was occasional scatter0d CB. s 6000′ to 30,000′. West of the trough 4 octas strata-cumulus 3500 deteriorating.

The first in a series of safety-related articles provided by Flight Standards Division of the Department of Aviation. Paul Middleton is a Senior Examiner of Airmen and heads up the General Aviation Crew Sub-section in the Flying Operations Branch of the Flight Standards Division. He has had extensive practical experience in the GA environment. Prior to joining the Department’s Vic/Tas Region in 1978, Paul had worked as a flying instructor, charter pilot, chief pilot, chief flying instructor and commuter pilot. He moved to Central Office of the Department in 1979 and now has 9,000 hours total experience.

David had also been advised that, “at this time”, Bankstown was CAVOK and winds were light and variable. As the trough was expected to reach Bankstown later, he advised David to ask for an update approaching Camden.

David thanked the briefer and like all pilots wondered if they had got it right. Wei! no worry, he would find out as soon as he was in the air. After analysing the information he had jotted down, he decided to fly West Wyalong – Cowra – Camden at 6000′ and from Camden to Bankstown at 2000′. The 6000′ would give him plenty of safe altitude over the Kanangra Walls and given no haze, should enable Bev and her brothers to pick out their parent’s property at Wirrinya.

He then set about completing his plan and finally was able to call back Bankstown and file it with some confidence. It was now 6. 30am local time and although he wanted to get ”wheels up” at 8. 00am on the dot (2200 UTC), he still had enough time to finish a second cup of coffee and study the WAC chart, check the navigational aids available from the visual en route chart and refresh his memory of the Bankstown General Aviation Airport Procedures.

The flight plan which he submitted to Bankstown Flight Service included the following information:

• the aircraft was PA28 Sierra Delta Quebec (why do FS always call the Warrior a Piper Cherokee?);

• the flight was a private VFR;

• the transponder was 4 and the aircraft had 1 ADF;

• ETD West Wyalong was 2200 and the route was:-West Wyalong – Cowra 6000 track 076 time 40 minutes Cowra – Camden 6000 085 Degrees time 48 minutes Camden – Bankstown 2000 track 032 time 7 minutes

• endurance was 209 minutes/114 litres and there were four people on board.

David met the rest of the party at the aerodrome as arranged right on 7. 30am. They were pleased to see him ready to go, but not before, as David pointed out to these “non-navigators”, he had undertaken a thorough pre-flight inspection and secured the baggage.

This took about ten minutes and the only item which David noticed was that the fuel was down a little under the filler necks by about what he thought was an inch, but as the flight was only to take about 90 minutes, he judged he still had quite sufficient. He signed Sierra Delta Quebec off as !’fit to fly” and announced to his passengers that the next flight to Sydney was leaving shortly and that intended passengers should board now. All checks complete, hatches and harnesses secure, David broadcast his intentions into the ether and taxied for runway 09. Because this was Bev’s first flight with him since the engagement he flew the plane strictly according to the numbers and lifted SDQ off the runway especially smoothly. He could see she was impressed. The boys didn’t appear to be interested.

As he was climbing through 2000′, David had his first contact with the anonymous Flight Service Officer in Sydney. “Sydney, this is Piper Warrior (he’d show them) Sierra Delta Quebec departed West Wyalong on the hour, tracking 076 on climb to 6000”. “Good morning Sierra Delta Quebec, QNH is 1017, call Sydney 124. 1 at time one zero”, and then he added “confirm aircraft is a PA28 Cherokee and not a Warrior”. David agreed, why fight tradition. David settled into the climb holding 80 knots and completed his after take-off checks. Everything in the green. At 6000′ he levelled-off SDQ, re-trimmed and leaned the mixture to 50 degrees on the rich side of peak, dialled in the Cowra ADF, identified it and settled back to enjoy the flight with his companions. The Western Districts of New South Wales are a pleasant place to fly and he was having no difficulty holding the ADF right on the Cowra aid. As instructed, he called Sydney at time one zero and reported cruising 6000′. Although he was a little behind schedule as Grenfell passed his port wing, the ADF needle was not deviating from the top of the dial and from his ground speed check he decided that the winds were not as strong as predicted so he called Sydney and advised a revised ETA Cowra of time 45 past the hour.

David had always thought that one of the magic moments of being a VFR pilot is when your reporting point comes up right on the nose, right on time and sure enough about 10 miles out he started to make out the familiar outline of Cowra.

A few minutes later, and after he was sure that his passengers were suitably impressed with his navigational abilities, David checked all instruments changed tanks, and as the ADF needle moved lazily around the dial till the needle was pointing at the 180, he called Sydney and reported “Cowra 45, cruising 6000′ Camden 28”. Sydney acknowledged and as he dialled in the new QNH, he gently banked SDQ onto a heading of 085 which would bring him over the top of Camden in about 3/4 of an hour. From there it would be a quick downhill run into Bankstown.

As Sierra Delta Quebec flew over Wyangla Dam, David noticed that there appeared to be quite an extensive build-up of cloud ahead at his altitude. However, whilst he now noticed that he was Consciously being more vigilant, he decided to remain at his present altitude and heading and if necessary advise the anonymous Flight Services Officer that he would descend to “Below 5000”. He knew from his careful planning the night before, and a quick glance at his WA. C chart to confirm, that he could make it to Camden at 4500′ and still maintain terrain clearance safely. About the time that David crossed the Crookwell to Blaney Road and he had identified Trunkey Creek out the port side, he noticed that the infernal ADF needle was beginning to react erratically. Instead of pointing confidently at Cowra like it had been, it was occasionally pointing fitfully at the rather menacing CBs up ahead. David advised Flight Service that he was descending to “Below 5000” and switched the ADF off to avoid distraction because he was now sure that electrical activity in the clouds ahead was producing unreliable signals.

David explained to his passengers, who were now also paying more attention to the progress of the flight, that he would have to monitor the weather closely and that if the weather was no better at Kanangra Walls, he would have to turn around and head back to Cowra. He explained that he understood their disappointment but he wanted no arguments. None were forthcoming as it happened. For the next few miles intermittent rain had been hitting the aircraft’s windscreen and in defiance of gravity had been streaking back, along the perspex horizontally. Patches of cloud were also starting to appear hanging down to 3500′ out of the bottom of the strato-cumulus.

Decision time, David thought, would have to be about 2300 if he was to ‘have sufficient fuel to return to Cowra with reserves.

There was no question of making it to Sydney today as David could now see at his se 0imposed decision time, that the clouds were on the mountain tops and the lightning flash had given them all a bit of fright even though it must have been at least 10 miles away.

David called Flight Service and advised that he was 60 miles East of Cowra, that he was returning to Cowra due to non-VMC on track and that his endurance was 120 minutes. As David turned SDQ around to a heading of 276 to track 265 degrees and changed tanks, he silently congratulated himself for having the good sense to turn back the first time he encountered deteriorating weather. His passengers assured him that, while disappointed that they would miss out on a couple of promising nights in Sydney, safety was the best policy. David felt a lot less anxious.

However, David’s anxiety returned a short time after this. He suddenly realised that while. he had been holding his heading accurately for some time, the terrain below looked decidedly unfamiliar. He recognised the Crookwell/Blayney Road, but could not be sure whether he could see Tuena. He also noticed that his left tank was down to well below a¼ full and the right tank was hovering just above the same reading. He took the time to recheck his calculations and was sure that he should still have over 100 minutes of endurance when his mind flashed back to his pre-flight. Both tanks were down lower than the filler necks. But how much down were they and, even if he could remember, how many litres would be involved? These are the stories that Aviation Safety Digest articles are made of, he grimly thought.

He had expected Wyangala Dam to come up on the hour, but it hadn’t and the terrain ahead was not falling away towards Cowra, instead steep rocky hills cut by North/South valleys seemed to go on indefinitely.

He started to doubt his navigational skills and tried to retrace the decisions he had taken. Maybe if the wind was not as strong as he thought, he had drifted to the north of track. That would explain no Tuena and no Dam. Now he was really concerned because the right tank was below a ¼ full and he was crossing another road with the cloud ahead down on the mountains and his altitude was 2000′.

What to do. His mind flashed back to his first cross-country navigation exercise and his instructor’s words – “if in doubt, ask, and that applies to all aspects of aircraft operation”.

Well it had to be done. David called Sydney and advised that he was unsure of his position and he believed he may be low on fuel. The Flight Services Officer seemed so relaxed. David certainly wasn’t and his passengers began to realise the implications of the exchange between SDQ and the voice on the other end of the radio.

David explained the headings he had been holding and the fact that he had just crossed a road with a power transmission line alongside it. After standing by for what appeared to be a long time, but what in reality was possibly only a matter of seconds, the friendly voice advised David that they believed SDQ was in fact some 20 miles south of Cowra and if he followed the road north he would discover Cowra within about 12 minutes. SOUTH – David could’t be sure. If anything, he would have to be north of Cowra.

You guessed it. Flight Service was right and David and his passengers arrived in Cowra safely.

What went wrong?

This story, and that’s exactly what it is, is a familiar story to many pilots.

The pilot had spent some time planning his flight, had access to sufficient information and, according to the pilot, conducted the flight safely, but it almost ended in disaster. WHY. Before I give the game away and analyse David’s problems, why not reread the story and follow his plan through either using a WAC chart of your own or the reproduction used in the article. See if

you can find out where David went wrong.

Now read on

Each year upward of 70 pilots find themselves in similar circumstances and request navigational assistance due to weather related problems. How many more pilots find themselves in David’s position, don’t ask for help and muddle their way out of it, we don’t know. Pilots should remember that the system is there to help them. If Flight Service doesn’t know your problem, it cannot help. It should also be remembered that, in every case where navigational assistance is requested, the Department takes no action in accordance with the long-standing immunity arrangements that the Department apples. In short, Flight Service is there to help you, not hinder you.

Now back to David’s case. Where did he go wrong? The very nature of the story would indicate that David’s navigational errors and subsequent “position uncertain” situation were primarily due to the fact that he obtained inadequate weather information and/or interpreted it wrongly. However, there were lots of clues available which didn’t seem to alter his decisions.

First, in flight planning, David put himself East of the trough where in fact it had already passed West Wyalong. The time of the forecast, the trough’s position and its speed should have been taken into account when David incorporated winds into the plan. You may have also noticed that despite this, David used true bearings instead of converting the wind direction to magnetic.

His first clue to the fact that the trough had passed should have been the runway he had to use for take-off (09 not 27). Despite these first oversights, there were other clues early in the flight that should have given David more accurate information to conduct the flight according to the plan.

Grenfell passed the aircraft on the port side where it should have been on the starboard. David noticed that he was behind time, but interpreted this, without cross-reference to track error, as the winds not being as strong as predicted rather than different direction and speed. If David had followed normal ADF procedure, he would have flown outbound from West Wyalong using the aid there and maintained a heading based upon his anticipated winds until he established the drift. This procedure would have soon indicated that he had about 10 degrees of starboard drift. Instead, he chose to fly “the needle” without reference to the heading. Of course, this approach brought him over the top of Cowra eventually, but from South of the intended track. He should have only dialled in the Cowra aid when he was about halfway between WWL and CWR. On changing aids, he would have noticed the drift also.

You may also have noticed that despite recognising that he was late at Cowra, he did not build this into the next leg. Because David, had often flown aircraft with ADF’s installed and had been shown the rudimentary of their use but was not endorsed he therefore, made another error as he set up for the Cowra – Camden leg of his flight. He took up the heading of 085, which was his track, not the heading required according to his own plan. However, he missed the next clue which was that he passed over the top of Wyangla Dam, not across the Northern extremity.

Obviously, David was being pushed South of track and he misidentified Tuena for Trunkey Creek. It is very easy to read into your situation what you want if you are not careful to cross-check with other information.

David was happy with himself when he decided to turn back but because he was not computing the weather situation, this is where the flight could have ended in tragedy. A 180-degree turn was not what was required to get back to Cowra and he ended up even further South of track with diminishing fuel in worsening weather. No place for anybody to be, let alone a low-time, VFR pilot.

The ending to this story is happy, although hopefully, David would have learnt a few valuable weather lessons. Not the least of which is that, given the forecast, David could have given some thought to planning his flight via a more Southerly route which would have taken him over much lower terrain, plus there would have also been a number of alternate aerodromes available. However, lets not forget two important things that David did right: – he turned back rather than press on into non-VMC; and he asked for navigational assistance as soon as he realised he was uncertain of his position.

Remember also that pre-flight preparation is the basis of air safety. It’s your decision.