Safety Accident Analysis
Night VMC… an illusion? To the unwary, ‘Night VMC’ might suggest that flying at night is conducted in the same way as by day – it’s just that bit darker. However, as we struggle with recency and lower total flying hours this year, Steve Ayres suggests these accidents come as a stark reminder that not everything at night is quite the same…
manager and emergency services reported that it was a very dark night and that there was no distinguishable horizon. Evidence was consistent with a slight right wing down, nose low, and high speed impact with the water. A right turn would have been necessary at some point after take-off to fly towards the destination airport and evidence is consistent that a right turn had been initiated. Although the reason for the impact with the water could not be determined, the overwater departure in dark night conditions would not have provided adequate visual cues to assure a positive rate of climb during the departure and initial turnout on course as a pilot would be vulnerable to illusions if flight instruments were not used to conduct the take-off and initial climb.
Accident 1
During the two-hour night time VFR instructional cross-country flight in a Beech 76 Duchess, radar data identified the aeroplane on an easterly flight track, when the first of two manoeuvres over mountainous terrain was initiated. The first manoeuvre was a left turn from about a 048° course heading to about a 176° course heading. Throughout the turn, the aeroplane’s altitude remained about 5,600ft mean sea level (msl), and the ground speed decreased to 55kt. At the completion of the turn, the ground speed increased to about 67kt, and the aeroplane began to climb to 6,600ft msl. The aeroplane then made a right turn course reversal and resumed the easterly, heading for about 10 miles
The instrument-rated pilot took off in dark night conditions over a lake that bordered the upwind end of the runway. The airport manager witnessed the PA32RT depart and reported that the take-off sounded normal. Two witnesses who were facing the lake reported that they observed an aircraft take-off from the airport, and fly about 100 to 200ft above the lake surface. It then banked to the right and disappeared from sight. About 10 to 15 seconds later, the witnesses heard what sounded like a crash into the water or an explosion. There were no distress radio calls from the pilot and there was no radar information for the flight. The airport
Accident 2
“It was a very dark night and there was no distinguishable horizon” 44 | FLYER | February 2021
before a second left 180° turn manoeuvre at an altitude of 6,200ft msl and a ground speed of about 121kt. At the apparent apex of the turn, the aeroplane was at 6,100ft msl and a ground speed of 50kt. The aeroplane then began to descend, and the ground speed increased to 74kt and then decreased to 50kt. The last radar return showed the aeroplane at an altitude of 5,700ft msl and a ground speed of 67kt near the accident site. Radar data revealed that both manoeuvres were similar, except that the second manoeuvre began over higher elevation terrain. The aeroplane’s separation from the terrain during the second manoeuvre was as low as 1,200ft above ground level before radar contact was lost. Weather reporting in the area of the accident site indicated extreme turbulence and severe up and downdraughts during high wind conditions. Although there is evidence of strong wind in the area at the time of the second manoeuvre, there is no consensus among the available wind data. However, the upset occurred immediately downwind of relatively high terrain and inside of a temperature inversion, which can promote wave action and turbulence. Thus, the aeroplane likely encountered a downdraught and the pilot was unable to recover, resulting in the aeroplane’s subsequent impact with terrain. The instructor was newly hired and this was his first instructional flight with the company. A representative of the operator reported that manoeuvres were usually performed to facilitate a two-hour flight. All flight was barred below 500ft agl and minimum cruise altitude of 2,000ft agl in mountainous terrain. It couldn’t be determined if the pilot or flight instructor were aware of the weather conditions or terrain elevations while doing the manoeuvres.
Accident 3
At about 1827 a privately registered Cessna 150M, with a passenger seated
Mark Mitchell
I
have always been slightly troubled by the term ‘Night VMC’, not for its strict definition, more for what it seems to imply. I can certainly remember when instructors would say to me ‘it is pretty much the same as flying in the daytime, but it’s just dark’. I may be alone in never quite finding it that straightforward. Getting the balance right between instrument attitude references and ensuring my own anti-collision with what seemed totally inadequate lookout queues, was always a challenge. Add to that all those sensations experienced when accelerating and decelerating, pitching and rolling, and it definitely made night flying a dark art that took some serious training and regular practice. The following accidents suggest having such a healthy regard for the potential pitfalls is the safest approach.
