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…

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.

Accident 1

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 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.

“It was a very dark night and there was no distinguishable horizon”

Accident 2

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 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 on the right and the pilot seated on the left, took off from the Montréal/ St‑Lazare Aerodrome, Quebec, for a night flight under visual flight rules. At approximately 1830, the aircraft conducted an approach to Runway 07 at the Montréal/Les Cèdres Aerodrome, Quebec, followed by a go‑around.

The aircraft then conducted a 180° turn over the interchange between Highway 20 and Highway 30 and flew westbound over Highway 20 at a very low altitude. At approximately 1834, the aircraft conducted another 180° turn, flying eastbound over Highway 20 at a very low altitude. When it was close to the interchange between Highway 20 and Highway 30, the aircraft turned south and flew over Highway 30, still at a very low altitude.

At about 1836, nine minutes after take‑off, the aircraft struck power lines crossing Highway 30 at kilometre 7 and crashed to the ground. The two occupants received fatal injuries.

Accident 4

A Piper PA‑28‑181 aeroplane, was substantially damaged when it was involved in an accident in Blairsville, Georgia. The private pilot and two passengers were fatally injured, and another passenger was seriously injured. According to the passenger, who was in the front right seat, the take‑off was normal, and they flew around the local area to look at Christmas lights before returning to the airport. As they got closer the passenger could see the lighted runway in front of them.

During the approach, the pilot described to the passenger that he needed to hit ‘markers’ on the GPS that he was using for navigation as the aeroplane approached the runway. She said the pilot was relaxed and didn’t seem to have concerns about the flight. The aircraft’s engine was running fine, with no unusual noises in the cockpit.

Everything appeared normal. The next thing the passenger remembered was seeing rescue personnel. The pilot’s handheld Garmin GPSmap 496 was located in the wreckage. A review of the data revealed that, at 1936, the aeroplane was inbound for Runway 08 on a heading of about 074° at a groundspeed of 63kt at a height of about 186ft above airfield elevation.

Eleven seconds later, the aeroplane had descended to a height of about 77ft above airfield elevation and had suddenly turned to a heading of 023°, when it was about ½ mile from the end of the runway and shortly before data recording ceased. The pilot had logged 15 instrument approaches in the six months preceding the accident.

“The runway can seem out of position and in the worst case, results in landing short”

However, the types of approaches were not recorded. His last recorded flight at night was four months earlier, at which time he logged only one landing.

The published inbound course for the RNAV (GPS) RWY 08 instrument approach was 076°. The RNAV (GPS) RWY 8 instrument approach plate stated that the approach was not authorised at night and had a minimum descent altitude equivalent to approximately 1,030ft above airfield elevation. According to the FAA, a ‘black hole’ approach occurs when the landing is made from over water or non‑lighted terrain where the runway lights are the only source of light. Without peripheral visual cues to help, orientation is difficult. The runway can seem out of position (down‑sloping or up‑sloping) and in the worst case, results in landing short of the runway. If the runway has a city in the distance on higher terrain, the tendency is to fly a lower‑than‑normal approach.

Ayres’ Analysis

After reading this eclectic collection of accident reports it is difficult not to conclude that VFR flying at night exposes us to very particular risks more akin to flight in IMC than flight in VMC, especially when in ‘dark night’. Starting with ‘brakes off’ the take-off needs to be conducted in much the same way as would be the case for an IFR departure. Granted, many airfields are brightly lit or border brightly lit spaces, but many are not and those inky black spaces can become a tempting go-to place if attention is allowed to wander from the instruments for too long.

Having slipped the surly bonds of Earth and clambered skywards, more challenges await when manoeuvring without normal visual references. Unable to see the ground and blind to the normal sensations which accompany flying by day around hilly terrain, vertical currents turned what should have been some benign general handling manoeuvres into disorientation and ultimate loss of control with fatal consequences. While the third accident was more about the risks of night low‑level sightseeing, it does illustrate that even when there is plentiful artificial illumination, spotting obstructions can be extremely difficult.

Having successfully navigated the upper‑air portion of the flight, the recovery is not entirely hazard free. Devoid of accurate glide path information, the pilot in the last accident was obliged to carry out the latter part of his approach on the aspect of runway lights. Challenging in the best of circumstances but when accompanied by rising ground on the approach, potentially disorienting street lighting and poor recency, margins can quickly become eroded with fatal consequences. Understanding potential hazards on the approach is, of course, an essential part of flight preparation and should extend to cover those on the approaches at diversion airfields and incorporate possible runway changes too!

Perhaps unsurprisingly, it is most unlikely any of these accidents would have occurred in day VMC and yet it is all too easy to fall into day VMC mode when flying at night. Ensuring a correct scan of instruments and the outside world, observing proper safety altitudes at all stages of flight and making sure the approach has been thought through in order to remain clear of hazards will go a long way to keeping safe. Plus, of course, the usual requirements of being qualified, current and free from impairing drugs. So is operating in night VMC the same as day VMC, but just a bit darker? For the most part, yes, but with some really, really important differences!