On 15 June a thread appeared in PPRuNe DG&P General Aviation and questions. It concerned a fatal accident at night to a Cessna 310 that crashed very shortly after takeoff at Bathurst Island. NT. ATSB published a possible cause as somatogravic illusion that may have caused the pilot to mis-read his instruments. It was pure speculation because ATSB were unable to pin-point the real cause of the accident.
With most general aviation light twins of that vintage, the absence of recording data in the aircraft inevitably means the cause of accidents of this type is unknown - not a satisfactory outcome considering most pilots try to learn from accidents to others.
Some years ago in Auckland, a Convair 580 (turbo-prop version of the Convair 440 Metropolitan) flew into the water shortly after liftoff on a dark moonless night. It was the first officer's first flight in a Convair and she was was conducting the takeoff from the copilot seat as part of endorsement on type. The aircraft carried a known defect to the copilots artificial horizon in that on previous flights it was known to give faulty pitch and roll indications. The Convair used flaps for takeoff and normally these would not be retracted until the aircraft reached a safe height - nominally 500 feet. This was because there could be a marked trim change as the flaps retracted.
The investigation revealed that the captain had a personal habit of selecting the flaps up as soon as the landing gear started to retract - in other words around 100 feet. . Like most aircraft of its type, flap retraction caused a nose down change of trim. The Convair never got above 150 feet before it gently nosed over into the water. The crew did not survive. The investigation revealed the first officer was not only faced with a black night departure for her first trip on type but also had a faulty artificial horizon and a captain who was in the habit of retracting the flaps unannounced at a very low altitude.
A similar crash happened in 1950 at Camden when a Lockheed Hudson crewed by two pilots took off shortly after midnight into poor visibility and drizzle. A witness observed the landing lights of the aircraft as it climbed and then as it descended into rising ground half a mile from the departure end of the runway. The captain was an experienced Hudson pilot with many night take offs to his credit. The investigation into this fatal accident concluded (speculated) the aircraft had stalled during initial climb and recovery was not possible at that height. Why did the Hudson stall? It was impossible to say.
It has been always known that some types of suction driven artificial horizons are subject to acceleration errors where pitch and bank angle errors may cause the instrument to give erroneous information. Typically, acceleration on take off will cause a slight angle of bank and slight pitch attitude change in the artificial horizon. Pilots are warned to cross-check with their compass and turn and bank indicator to ensure they are not foiled by acceleration errors on the artificial horizon. Some vintage artificial horizons may have a gyro caging mechanism to aid quick erection of the AH should it topple in a steep turn or when first starting the engines. In theory, before take off drills should include checking the gyro caging mechanism is indeed uncaged. It doesn't take much to imagine what could happen if the aircraft takes off at night with its artificial horizon locked in the level flight (caged) position.
The following story written a few years back by a RAAF flying instructor reveals how even an experienced pilot can relax his concentration on his instruments during a night take off and find himself in a `Nearer My God to Thee`, situation. (With apologies to the author of that well known hymn)
The story is called:
"A Likeable Bloke"
The first officer calls him “Captain” or “Skipper” although one well known low cost carrier even allows “Mate.” The latter airline prides itself on team spirit where everyone is considered equal. I am talking of course about the captain of an airliner. Back in the Fifties when I was a lowly Sergeant-Pilot, if the captain was a commissioned officer he was “Sir” although “Skipper” was OK while airborne.
This story does not entail airliners but rather a large twin-tailed four-engined bomber originally called a Lancaster Mk 4 - later renamed the Lincoln. My squadron was equipped with eight of these aircraft as well as a Mustang and a Wirraway and we were based at Townsville in North Queensland. Those who fly regularly to Townsville will know that runway 01 is the main runway; the northern end not far from the sea with the 1600 ft high peaks of Magnetic Island just five miles ahead on the extended runway centerline.
Among the squadron crews were experienced pilots who had braved anti-aircraft guns and night fighters over Nazi Germany during the Second World War. One such veteran had recently been posted to the squadron from a desk job in RAAF Headquarters and he was eagerly looking forward to getting his hands on the Lincoln. A delightfully cheery character he wore a row of campaign ribbons including the Distinguished Flying Cross (DFC) and held the rank of Squadron Leader. For the sake of anonymity I shall call him Bill. At the time, I was the squadron qualified flying instructor (QFI) appointed to conduct type rating and instrument rating tests. With twenty pilots to look after I was kept busy with both day and night flying.
Bill was scheduled to undergo a night proficiency check on the Lincoln; a difficult aircraft to land at the best of times because of the limited view over its long nose. Our version was in fact called the Long Nose Lincoln to distinguish it from the original blunt nose of the Lancaster.
Now, while Bill was far more experienced on bombers than I as his instructor, he was not that current on night flying – hence the reason for a dual check. Always in a teasing manner he made it clear he felt the dual check was unnecessary given his extensive night flying experience; much of it over hostile territory. In turn I had learned the hard way that many flying hours in a log book did not always add up to top class competency.
Apart from a few lights from holiday shacks on the beaches of Magnetic Island, there was nothing but sheer blackness over the water after take off. The wind was calm; a great relief as far as I was concerned, especially as cross-wind landings at night in the Lincoln were not easy. The instrument panel was designed for single pilot operation with no flight instruments for the copilot or instructor. The copilot’s seat was a small fold down stool set below the level of the pilot who sat on a raised pedestal. In order to monitor the pilot’s instrument flying it was necessary for the instructor to lean well over to see the instrument panel to avoid excessive parallax error.
After Bill had conducted several touch and go landings I briefed him that after the next take off, we would turn right out of the circuit and climb to 4000 feet on instruments before returning for a VHF/DF instrument approach and let-down. His landings were well executed and I began to relax a little knowing that his hard earned experience would make an instrument let down a piece of cake.
At five hundred feet after take off, Bill asked for the take off flap to be retracted and accelerated towards the en-route climb speed of 140 knots. As he turned a few degrees right on course to Cape Bowling Green (a coastal headland invisible in the darkness and 20 miles away), I adjusted the four pitch and throttle levers to set climb power. Like most aircraft of that era, retraction of the flaps caused a noticeable pitch down trim change. The unsteady beat of engine noise indicated the propellers were not synchronised and so I concentrated on moving the offending pitch control lever until the revs were all equal.
It was then I noticed out of the corner of my eyes that the needle of the rate of climb indicator previously pegged at 500 feet per minute, was now showing level flight and that the altimeter had stopped its steady climb. From 140 knots the ASI was now showing a slow but steady increasing reading. Bill was locked on to instruments but seemingly unaware of the attitude change caused by the slow retraction of the flaps. As an instructor I had observed a similar problem during the course of night instrument departures, but rarely with experienced pilots.
Very gently the VSI began to show a descent, the little aeroplane of the artificial horizon showing on the horizon bar and not above it. The aircraft was now in a rate one right turn and slowly descending from a peak height of 800 feet above the sea. Obviously, Bill was unaware of the impending danger and I had to decide whether to warn him then and there – or see if and when he spotted the problem. The low range radio altimeter furnished the extra confirmation we were definitely descending. At 300 feet indicated on the radio altimeter it was time to act and I called urgently through the oxygen mask microphone “ Watch the VSI – Sir!” With that came an oath from the squadron leader who jerked back on the control column into a climbing attitude.
There was no doubt in my mind that the Lincoln would have eventually hit the sea except for my support call. The rest of the flight was uneventful and after we had landed, I gently reminded the squadron leader of the need to watch the trim change with flap retraction - especially in IMC. Perhaps it was a momentary aberration that could happen to anyone, but certainly he could offer no explanation.
Some weeks later I was posted to a desk job in Melbourne but not before I had briefed my replacement on the event described. That short discussion may have prevented a potential accident in the months to come. The squadron had deployed several Lincolns to Darwin for anti-submarine exercise with units of the Royal Australian Navy. One of the captains was Bill the squadron leader. His copilot was a young Sergeant recently graduated and with precious few hours on the Lincoln.
On completion of the deployment, the Lincolns departed for Townsville at midnight – a flight of seven hours. Navigation was by astro sextant and high frequency radio bearings, with each aircraft setting course from over the top of Darwin aerodrome. This required a climbing right turn after take off. The departure flight path lay over mangrove swamps to the immediate south of the airport and home to hordes of crocodiles; certainly not an ideal place to ditch. Each Lincoln carried several passengers – ground crew or spare pilots - one of whom was the new flying instructor who had replaced me. The noise level down at the back of the Lincoln was incredibly painful to the ears and the instructor decided to sleep in the bomb aimer’s seat in the nose of the aircraft where the view was superb. The captain of that aircraft was Bill.
The night was dark with occasional moonlight slanting through low level broken cloud cover. Bill conducted the take off and easing into a climbing right hand turn at 500 feet, he asked the copilot for climb power then flaps up. With four throttles and four pitch levers to contend with the inexperienced copilot concentrated his attention on adjusting the four manifold pressure and rpm needles, cursing quietly into his switched off microphone at the unsteady beat of un-synchronised propellers. It is clear he could not have been monitoring the flight instruments at this critical stage of departure otherwise he would have surely seen the VSI gently moving from positive rate of climb to gentle rate of descent.
In the bomb-aimers seat, the instructor glanced at his watch and made a mental note of the airborne time. Soon after he felt the gradual sink as the flaps were retracted and heard the change of propeller synchronization indicating the setting of climb power. A single moon beam reflected briefly off the rancid waters of the mangrove swamp below and then darkness as the Lincoln flew through patches of low cloud. Seconds later another moon beam allowed the instructor a fleeting brief glimpse of the ground – this time measurably closer. The normally imperturbable instructor quickly realized the aircraft was much lower than before and still descending. In an instant he recalled my earlier warning about Bill’s flight with me a few weeks earlier and switching on his microphone he shouted “For Christ’s sake Pull up – Pull up.” There was a muffled oath from “Sir” in the left hand seat and the aircraft began to climb…..
Soon after this incident, the Lincolns were replaced by Lockheed Neptune long range anti-submarine aircraft. Among the crews posted to undergo the Neptune conversion course was Bill the squadron leader. He was to be flight commander of the new Neptune squadron at Townsville. Despite his engaging personality and undoubted high quality flying experience, Bill, perhaps fortuitously - failed the conversion course; deemed lacking the skills to fly the Neptune – a modern sophisticated type after the basic wartime design of the old Lincoln bomber.
Instead he lived to serve out a well earned retirement desk job posting as Commanding Officer of a small Air Training Corps unit close to his boyhood home. All this happened nearly sixty years ago so Bill would be well over 80 years old by now, if he is still around. I hope he is - because he was a likeable bloke.