Safety Corner: Plan Continuation Bias

“ Plan continuation bias”, by Warren Le Grice

Welcome to the “ Safety Corner”. I used to write a similar column, when I was a member of the Boundary Bay Flying Club. I have been involved in the promotion of flight safety for many years and will continue to do so with the AFC.

In the early 1990s, when the ATC system was still operated by Transport Canada, I had an opportunity to participate in a 20 month secondment with System Safety Branch, as a Regional Safety Officer . At the time I was working as a Course Director in our Regional Training School at the VR ACC.

I was fortunate enough to work with an excellent mentor, during my time with System Safety, Vince Edwards, an experienced fixed wing and helicopter pilot. During my time with the Safety Branch, I developed a keen interest in human factors and why pilots make the decisions they make. I was tasked with delivering the PDM ( Pilot Decision Making) course to Flying Schools and Flying Clubs around  B.C. A side benefit to the secondment was the opportunity to receive dual on both Transport’s amphibious  Beaver C-FDTI and the Jet Ranger C-GCGQ.

With the preceding narrative as some background, I can now relate the story of my first aircraft partnership, what happened to the aircraft and one of my partners.

I controlled  at Vancouver Tower from 1971 to 1979, a very interesting airport to control  during that time period. My first aircraft partnership was in a 1968 Piper Arrow, CF-UKE. My four other partners and I purchased the airplane in 1979. I was able to build up my IFR experience in the airplane over the next couple of years and was able to give one of my partners, Dave, most of the dual he needed to get his instrument rating.

We had one good cross country from Carson City, Nevada, back to Vancouver, in the Arrow, as one of the partners got weathered in, and wisely decided to return to VR by airlines. Dave and I were able to  practice all the IFR approaches in the lower mainland and southern Vancouver Island, including Nanaimo. Now in the early 1980s Nanaimo had only one NDB approach which terminated at the YCD NDB, if you didn’t see the airport from the beacon inbound, you carried out the missed approach, so obviously the limits were quite high, probably about 1000 feet and 3 miles.

I do remember advising Dave to take it easy, and be careful as he built up his experience, after he achieved his instrument rating. The Arrow had only 2 VOR/ILs receivers, no DME and no de-icing capability was really just a fair weather IFR airplane. Unfortunately as he got more experience in the airplane, he would take on IFR flights that I wouldn’t attempt, and once told me about an icing experience he had going into Port Hardy.

In 1981 when the mortgage rate went to 19 ¼ on our home in Burnaby, I decided it was time to sell my share in the airplane. It would be approximately a year later when I heard on the news, that UKE had crashed into a mountain, south west of the Nanaimo airport. My first thought was, what was the airplane doing going into Nanaimo at night? We kept the airplane on the south ramp at Vancouver, so I couldn’t figure out what reason there would be for flying into Nanaimo at night, on that fall evening. I concluded the pilot must have been Dave, as he was the only IFR rated partner at the time.

I got the full story a couple of weeks later, from one of my ex partners who was an electronics  tech with Transport Canada. Dave was a keen bird hunter and had flown over to Alberta with his youngest daughter, to shoot geese and ducks around Brooks, Alberta. He had asked permission of a farmer to shoot on his property, and after the hunt was invited in for coffee. The farmer’s sister –in –law, was visiting from Port Alberni, having travelled out by Greyhound. When Dave was told she would be returning soon, he volunteered to fly the lady back as far as Nanaimo as he had a spare seat.

The aircraft was on an IFR flight plan to CD, and as is often the case, the weather was deteriorating in the lower mainland, as the flight progressed from Alberta. Dave was likely anticipating doing an approach in VFR conditions upon his arrival. Now we had never done a night landing at Nanaimo as part of training, and I don’t know if Dave had ever done one once he was on his own. As the flight progressed through the Vancouver Terminal airspace, and was approaching Nanaimo, UKE was cleared to the Nanaimo airport for an approach, radar service was terminated and a the frequency change to Nanaimo radio was given. During the early 1980s VR Terminal controlled both CD and YJ airports as well as VR as there wasn’t anywhere near the IFR traffic there is today.

The last communication from the aircraft to Nanaimo Radio was, “are the runway lights on? ” The aircraft failed to arrive and was located a day or so later, having flown into the side of a mountain located a few miles south west of the airport. The aircraft was in level flight, likely in cloud and hit a large tree almost head on, killing all three occupants instantly.

The accident was a classic CFIT ( Controlled Flight Into Terrain) situation, likely brought on by pilot fatigue, stress and not being prepared to do a non precision approach, following a long day.

There is an interesting side note to this story. A couple of years later at the Area Control Center, I was facilitating a series of  human factor workshops for all Transport Canada control and FSS staff in the province. The subject was “ Situational Awareness”, and the first question I asked each class was, had they ever had an experience where  loss of situational awareness had lead to an accident or incident? On different workshops, the Terminal controller who cleared UKE for the approach that night, and the Nanaimo FSS who last spoke to the aircraft, related their stories. The FSS member had the family of the passenger who was headed for Port Alberni, waiting at the counter in the FSS, for word of their family member. It was a tragic experience for all involved.

So what can we take away from this accident?

NASA has recently come up with a new term “ Plan Continuation Bias”. The premise is when the pilot has somewhere to get to, he or she ignores the environment. The more the person has invested in the plan, the less likely they are to change that plan. Another way of putting it would be to say when a journey is almost over, people tend to go into auto-pilot, ignore changing and potentially dangerous environmental factors.

Had my ex-partner decided as they approached his home base in Vancouver, “gosh I am tired, let’s just do the ILS onto runway 08  and we’ll put the lady in the back seat ,on a ferry tomorrow”, I have already saved her a very long bus ride”. Had that been the case, his wife would have grown old with her husband and younger  daughter and the older daughter would have had a Dad and a younger sister.

Know your aircraft’s limitations and more importantly know your own.

Fly professionally and make good decisions.

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