Flying the Alaska Highway...VFR?
The following is based, in part, on a CTAISB accident report, but also on my experience as a long-time mountain-flier. The transition from flat-land flying to mountain flying is a difficult one for many pilots. In flat country or over the water, if you are uncertain, you can climb to a safe, familiar altitude and go for miles until you get your head together or get help. In the mountains, if you are not in clear VFR conditions, you had better be on instruments, at an altitude well above MOCA.
Food for sober second thought in this tale has been inserted in italics for emphasis. — Ed.
The TSB accident synopsis reads:
“The Piper PA 32-301T Saratoga departed Fort Nelson, British Columbia, on a visual flight rules flight to Beaver Creek, Yukon. When the aircraft failed to arrive at the destination, a search was initiated. The missing aircraft was found six days later by a Canadian Forces Search and Rescue aircraft. It had struck a steep, rocky slope in mountainous terrain at 6000 feet above sea level. The aircraft was destroyed and both occupants sustained fatal injuries.
The Board determined that the pilot attempted to continue visual flight in adverse weather conditions.”
The pilot, a retired US Navy pilot with about 5000-hours military 350-hours civil experience, and his son were on a long-range pleasure flight from California to Fairbanks, Alaska, via the Alaska Highway route.
They had arrived at Fort Nelson after two days of flying from California. The next morning, the pilot received a detailed telephone briefing from the Flight Service Specialist at Fort Nelson, covering the enroute weather along the Alaska Highway route from Fort Nelson west to Watson Lake, Teslin, Whitehorse, and Burwash.
The area forecast indicated that a series of trowals were moving across northern B.C. and southern Yukon, producing low ceilings, rain and fog. The Fort Nelson to Watson Lake leg was forecast to be good with ceilings 3000 - 5000 feet above ground. Very marginal VFR was forecast from Watson Lake to Teslin with overcast ceilings at 4000 feet ASL and layers to 20,000 feet in a very moist airmass (airport elevations rise from 1250 feet ASL at Fort Nelson to 2262 feet ASL at Watson Lake, 2313 at Teslin, 2305 at Whitehorse and up to 2647 feet ASL at Burwash). Visibilities were forecast at two to five miles in rain and fog. Occasional rime and mixed icing were forecast in cloud above the 6000-foot freezing level (the Watson Lake-Teslin run is about 120 NM, and the terrain between the two aerodromes rises well above the 6000-foot level). Conditions were forecast to remain poor throughout the day.
The pilot also received the latest actuals from along the route:
Watson Lake: 200 feet overcast, 4000 overcast, visibility six miles in light rain, temperature/dew point spread zero — both three degrees, winds three knots (AWOS report explains the two overcast layers). Question the forecast accuracy or at least think about the local effects of terrain.
Teslin: 1800 thin broken, estimated 4500 broken, 5500 overcast, visibility 15 in light rain, temperature/dew point both seven.
Whitehorse: special at 09:30 a.m.: partially obscured, measured 700 overcast, visibility two in light rain/fog, temperature/dew point both seven degrees (again questions about forecast accuracy and terrain effects).
Burwash (85 miles from destination): 1500 scattered, estimated 3500 broken, 9000 overcast, visibility 20 in rain showers, temperature four, dew point three.
(A VFR planner should especially note the temperature/dew point spread at all these locations, particularly in September, in the mountains.)
At the end of the weather briefing, the pilot remarked to the FSS Specialist that it would be a day to “hunt and peck”. He indicated that he would either return to Fort Nelson or “stay at the one I can get to” if he encountered unfavourable weather. (If?)
Witnesses who spoke to the pilot before his departure from Fort Nelson reported that he appeared to be excited about "flying the Alaska Highway" for the first time. A Yukon pilot very familiar with the route offered to give the pilot a preflight route briefing — the pilot declined. (Local knowledge, especially in the mountains, is generally far superior to any other advice obtainable.)
The same Yukon pilot departed Fort Nelson 45 minutes prior to the PA 32, en route to Whitehorse. He landed at Watson Lake due to the poor weather one half hour before the PA 32 passed overhead. He reported ceilings of 100 to 200 feet and low visibilities 14 miles southeast of Watson Lake. His report was later passed to the Saratoga pilot as he PXed his position near Watson Lake.
The pilot had owned the Saratoga since 1983. It was turbocharged, fitted with an oxygen system, and equipped and certified for VFR, IFR, day and night flight in non-icing conditions. It had been maintained in accordance with regulations.
The aircraft had hit the 32-degree mountain slope in a wings-level, nose-level attitude. Due to the complete destruction of the aircraft at impact, it was impossible to determine whether any pre-impact problems had contributed to the accident — none could be identified, but flight control surfaces were accounted for and the engine had been developing considerable power at impact
The enroute tale is short. He departed Fort Nelson at 10:26 a.m. At 12:13 p.m., he contacted the Watson Lake RCO and advised that he was 24 miles south of Watson Lake at 6000 feet. He requested and was passed the current weather for Teslin, and was advised of IFR ceilings further to the west at Whitehorse.
When the aircraft failed to arrive at destination, a search was started. Poor weather prevented effective searching for several days.
Two days after the aircraft was reported missing, a hunter called the Rescue Centre. He reported hearing a light aircraft flying overhead early in the afternoon on the day of the accident. He believed that it was the same aircraft flying from east to west three or four times (hunt and peck?). He reported that, at his position 50 miles west of Watson Lake, the ground visibility was one mile in mixed rain and snow. He also reported that all the mountain peaks and ridges were obscured in cloud with the cloud base below the 5300-feet-ASL level.
Searchers concentrated their efforts around the area of the report, and several days later located the crash site six miles north of the Alaska Highway.
A VFR chart with the proposed route highlighted was found in the wreckage. However, the crash site is on the centreline of the R5 air route between Watson Lake and Whitehorse — six miles north of the highway. The aircraft ADF set was turned to the Watson Lake NDB. The 6000-foot level of the site coincides with the pilot’s last reported altitude, but it is 2800 feet below the published Minimum Obstruction Clearance Altitude (MOCA) for the route. The wings-level nose-level aircraft attitude at impact would indicate that the pilot took no evasive action to avoid the mountain. The toxicological tests found no evidence of incapacitation or physiological factors that could have affected the pilot’s performance. Also found in the wreckage were the remnants of a hand-held GPS.
(After failing to get through VFR, was the pilot trying to get to the reported better weather at Teslin using his ADF and hand-held GPS ?)
Originally Published: Aviation Safety Letter Issue 4/1996
Original Article: Flying the Alaska Highway...VFR?