Since the beginning of powered flight, pilots have had one unifying dread – a dead stick landing.
I’VE READ MANY ACCOUNTS of the perilous early days of United States airmail flying in the 1920s like how Charles Lindbergh would have to land his de Havilland DH-4 on a short stretch of open land in the backcountry of the Midwest after his Liberty engine gave out.
Lindbergh eventually earned the name Lucky Lindy after his several near-catastrophic moments, including twice bailing out from a dead-in-the-air bird. But we must remember that, by all accounts, it was more skill than luck for this pioneer. Out of pure necessity, Lucky Lindy had developed a sixth sense, a little voice that reassured him: about the health of his bird’s powerplant while flying over hostile land and water, through bad weather and in the dark of night.
He also taught himself to fly with a bit of “money in the bank” – altitude. As the adage goes, “Airspeed is life, Altitude is life insurance.” He may not have said it that way, but he sure lived it. And long he lived – to the ripe age of 72, during which time he mastered the risks of flight, including the famed 30-hour Atlantic crossing in a single-piston-engine plane. He knew stuff.
But how does Lucky Lindy relate to helicopter flight and what can we process and learn through his life?
I’ve mentioned engines being naughty in some of my previous columns – like dropped valves, rocker shafts falling out… even Carl’s engine-coughing impressive 157-metre slide on landing in a crippled R44. All positive outcomes that produced Mount Everest shaped learning curves.
This time around, I would like to talk about some of the tell-tale signs of engine failures, how to avoid them firstly, quickly identify them if warranted, and finally how to deal with them safely. At the end of the day, a confident pilot will not neglect to listen to that little voice that we all develop over time with experience, like Lucky Lindy.
‘engine failures rarely happen the way they were taught’
The first thing to keep in mind as a pilot is that no engine is infallible. But like a human being, engines live and breathe and talk to you when you fly. As long as you listen. A small stutter from your engine in the night demands a pilot’s immediate and full attention, followed by what seems like a longer-than-usual flight back to base, as every small vibration and sound is earnestly dissected by your jacked-up-on-adrenaline mind.
Thankfully, engines, in general, do give fair warning of impending misery. Engine temperature and oil pressure instrument trends are not to be ignored. You should also carefully consider oil consumption, mag checks and engine performance during a flight.
A common misconception is that in helicopters, turbine engines are less prone to stoppage than reciprocating engines. This may be true to some extent, but they remain intricate mechanisms that can fail because of their many components and accessories.
Training is pertinent to a successful forced lob. In flight school, engine ‘failures’ are plentiful, as your instructor regularly snaps the throttle shut with a smirk and a swift left hand, sometimes with a “3-2-1 … Fail!” At other times, with no warning, the instructor tests the hapless student, hopefully in a safe flight regime, just to keep him or her sharp. Straight in, 180, 360, backwards, and side slip autos are to be mastered if there’s any hope of passing.
But the truth about real-life engine failures in general and on piston-powered Robbies in particular, is that they rarely happen in the way they were taught in flight school. On more than one occasion, my trusty Lycoming engine has dropped a valve into a cylinder and continued to run on the remaining 5 or 4 (the opposite cylinder is often also affected), albeit at a reduced power output. How does that look and feel?
Of note is how fast it happens.
Two immediate tell tales are how the nose deviates left and the sound of the Low RPM horn squealing, “PEEEEEEEEEEE!!!”
The nose drifts left because of the torque reaction pedal position (rudder pedals, if you will, for the plank drivers) being set for cruise power. With the engine problem, less torque is produced and there she swings!
‘no engine is infallible’
The Low RPM horn sounds and illuminates as the rotor tachometer passes below 97% rpm. This is not of too great a concern as you can recover the needed revs easily before 85% critical rpm. So, what do you do in the moment? Instinctively, in this situation, you would lower the collective, recovering the lost 5 per cent rpm and straighten the heading with the pedals set to less-to-the-left. And, of course, your head would be craned over to find the field you noticed as you whizzed past 30 seconds before.
More times than not, a real-life engine failure autorotation is successful, as long as the collective is lowered without delay and the rpm is stabilised into a smooth, steep glide. In fact, many more helicopter accidents occur with autorotations in the training environment than in actual engine failures.
In essence, flying has changed little in a century. The same perils that Charles Lindbergh faced are still relevant today. They may seem milder from the modern helicopter pilot’s point of view, but that perspective changes as soon as the engine quits.
Wisdom says to prepare well and to fly within your margins. Just like Lucky Lindy, who relied less on luck perhaps than his nickname suggests.