Questions to ask BEFORE you get on a light twin-engine aircraft.
When I lived in Hawaii, occasionally I’d lease and fly a Grumman Cougar (above), a light twin-engined propeller aircraft. The cold, hard fact with that aircraft was that if we took off with two passengers and their bags and lost an engine we were going down, period.
This I knew as a pilot–so I never flew the Cougar with any baggage, ever. But I think that many passengers might assume all is well either way–but it certainly is not.
This haunting memory always recurs every time I read of a light twin engine aircraft crashing on take-off, and sadly, that’s an all-too-common occurrence.
Some simple but vital questions could save your life if you’re thinking of chartering or accepting a ride on a light twin engine aircraft. But first, why do you have to ask?
The answer is simple: when you step onto my 175,000 pound twin engine jet–I have these answers specifically worked out for every flight, because the answers are crucial to all of us. You may assume that whoever is flying your light twin aircraft has answered them with specific numbers, but if you don’t ask, you’re casting your own safety to the wind. If your pilot has the answers–and provides them specifically (I’ll get to that later), step on board and have a good flight.
If your pilot says “Huh?” or even “It’ll be okay” or anything other than “here are the specific answers,” walk away immediately. Here are the Big Five:
1. What is the single engine climb gradient on this take-off, based on our projected weight and the current weather (temperature, pressure altitude and winds) conditions? Yes, I can answer that for every take-off with an exact number in two vital parameters: single engine (meaning assuming one engine quits on take-off) climb feet per nautical mile available and required.
“Required” means based on the terrain ahead, what is the minimum single engine climb gradient required for our aircraft to clear all obstacles by a minimum of 35 feet? “Available” means given our weight in fuel, passengers and bags, what is our aircraft capable of achieving on only one engine? Yes, there is a specific number to be derived from performance charts–and your pilot better have computed both. So your pilot should have a ready answer, don’t you think?
2. How much flight time does your pilot have in twin engine aircraft? Seriously, “total flight time” is not the important point here for a couple of crucial reasons. First, twin engine aircraft behave completely different from single engine planes because of the asymmetric yaw an engine failure produces. If one engine fails, the other continues to produces power and in many cases, must be pushed to an even higher power setting. Immediate rudder correction for adverse yaw–which doesn’t exist on single-engine aircraft–is a delicate operation: too much and the drag induced by the rudder kills lift; too little and the aircraft can depart controlled flight. Put in the wrong rudder, and you’ll be inverted in seconds.
If you’re paying someone to fly you somewhere, he’d better have at least 500 hours in that specific twin-engine plane–or you’d better walk away. In the above crash, the father of one of the survivors said the pilot had “flown the aircraft several times” and was “well-versed in it.” I stand by my 500 hour rule, at least when my life’s at stake. And “flight time” alone ain’t enough: proficiency, meaning hours flown within the past six months, is just as important. A few here and there? Not much recently? bad news.
3. What is our planned climb performance today? Meaning, given our gross weight in fuel, passengers and bags, at the current temperature and pressure altitude, what climb rate can we expect on a single engine? Again, this is a specific number derived from performance charts after all of the above variables are computed–and if your pilot doesn’t have the specific answer–walk away.
4. What is the engine history on this aircraft? Seriously? Yes, dead seriously: before I accept any aircraft for the day, I scan the engine history of repairs, malfunctions, oil consumption, vibration and temperature limits going back at least six months. Ditto your light twin: the pilot should be able to answer that question in detail–if the pilot checked.
5. How many pilot hours does your pilot have in this model and type of multi-engine aircraft? And when was the pilot’s last proficiency check? For example, I consider myself to be a low-time 737 pilot, having just over 1,500 hours in the aircraft–even though I have over 17,000 hours in multi-engine jets. In those 1,500 Boeing-737 pilot hours, I’ve had two complete refresher courses with FAA evaluations, plus three inflight evaluations–and I welcome that: I want to know my procedures and skills are at their peak. And I fly at least 80 hours a month, maintaining proficiency. When was your pilot’s last flight? Again, how many flight hours in the past six months?
Not withstanding “well-versed” and having “flown it several times” as quoted above, your pilot needs to have hundreds of hours in the model and type to be flown, and preferably hundreds of hours in multi-engine aircraft. Remember the engine-out scenario on take-off I sketched out above, where the wrong rudder input can flip you inverted on take-off if an engine failure? Ditto on landing, with another set of problems, in the event of a single-engine go-around with a lighter aircraft.
Know the answers to these questions, and have your radar tuned for the following circumstances: how far are you going (short hop versus a longer point to point), and how many are on board, plus what cargo (baggage or equipment). Why? These are your cues that gross weight is going to be a critical factor in aircraft performance, making the five questions I just raised even more critical for you to ask.
Look, there are plenty of safe aircraft and pilots available to fly you around if that’s what you had in mind. Those pilots are the ones who have good answers to the above questions ready for you as soon as you ask. Be sure that you do ask, and when the answers are satisfactory–and only when they are: bon voyage.
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