The laws of physics that allow flight to take place are fortunately for us, consistent. If enough molecules of air pass over a lifting surface, enough lift is produced to lift a body heavier than air, always.
If an engine is mechanically healthy, gets the right fuel/air mix to each cylinder, a spark to explode that mixture, and enough lubrication to keep all the parts happy, that engine will run and produce power, always. There are very few reports of engines continuing to run with no fuel going into the cylinders, even though there may be plenty of fuel on board.
The laws of physics take no holidays, no time off, never sleep, just give consistent, predictable results. Pilots are trained, tested and retested on these phenomena because obviously they are necessary for safe flight.
But the lack of correct conditions necessary for flight are also predictable and consistent. Luck, hope, or wishful thinking will not change the laws of physics. Density altitude and weather can vary drastically. But density altitude can be calculated and with today’s technology, current and future weather can be brought to our fingertips in various ways. Weather on any flight should take no one by surprise.
The Mother-in-law of Nature (aka the laws of physics) knows the runway length and the density altitude. But she did not make your airplane. With diligence, decisions can be made that are black and white, yes/no, go/no go. Gray or very weak yeses should default to no. The aforementioned luck, hope, and wishful thinking have no place in the calculations. We must know before the flight if it’s a no go. After takeoff is not a good time to find out that we shouldn’t have.
Mother Nature is neither kind nor cruel – she is only consistent. The exact same conditions will produce the exact same result, good or bad. The airplane will fly or it will not. The tools and knowledge are available to find out. The briefing always ends with “fly safe”. –Les Lowman Feb12
- lift, flight, engine, cylinder, spark, mixture, lubrication, power, fuel, density altitude, decision making, flight planning