Precautionary Landing

By lex, on February 14th, 2010

The reciprocating piston engine that powers the vast majority of the general aviation fleet is a marvelous design, achieving acceptable power at minimum weight and maximum reliability. It is also, as a mentor of mine recently reminded me when I was being a trifle inconsiderate in my rate of throttle adjustments, a delicately whirring and clanking mass of mechanical parts and their associated dependencies striving in fierce opposition to each other. There is any number of things trivial and otherwise that can upset that delicate balance, and when it does, well: Things can get interesting.

When you first start training in single engine airplanes – once that whole “maintain flying speed” thing has been adequately emphasized – you are relentlessly drilled with the necessity to always be on the lookout for a suitable landing spot should the spinner stop. Precautionary landings are taught as well as engine out approaches. It’s not at all unusual in later familiarization flights to be in the middle of a maneuver and have the instructor pilot pull power on you, announcing a simulated engine failure. One of my first instructors told me that any VFR flight in a single engine airplane should be made by navigating from one off-airport landing site to the next.

In most single-engine jet aircraft, the procedures for an engine failure are admirably abbreviated and easily memorized: Fly the machine, get her some gas, get her some spark, and if all that fails turn her back over to the taxpayers. But in GA aircraft, that final option of pulling the ejection handle is rarely available. If the engine quits in a Cessna or Piper, your fate and that of your machine are inevitably conjoined. You will be landing with her, the only questions are whether either of you are to survive that landing, and in what kind of shape. Some of that depends upon preparedness and cool thinking, and some depends upon luck. The more prepared you are, the luckier you tend to be.

If you are lucky enough to find yourself in calm winds overhead a 5000 foot runway at 3000 feet AGL when the noisemaker stops making noise, things are relatively straightforward. If you are unlucky enough to find yourself over mountainous terrain at the limits of your performance margins when things go south, perhaps you ought to have chosen a more congenial route of flight.

The first single engine aircraft I spent any appreciable time learning to fly in was the T-34C Turbo Mentor. We were equipped with parachutes as a matter of course, but in the case of an engine out landing we were expected to fly her in, if it was at all possible. The emergency procedures checklist has a number of “boldface” items that had to be memorized, repeated verbatim upon demand and demonstrated, both in simulators and in flight:

*1. Flying speed — MAINTAIN (100 KIAS minimum)
*2. Landing gear and flaps — UP.
*3. Engine instruments — CHECK.
*4. Condition lever — FEATHER (as required).
*5. Landing site — SELECT.
*6. Harness — LOCKED.
*7. Airstart — PERFORM (if situation permits).
If airstart is not attempted or is unsuccessful:
*8. No landing site available and altitude permits —
BAIL OUT.
If forced landing is to be continued:
*9. Condition lever — FUEL OFF.
*10. Emergency fuel shutoff handle — PULL.
*11. MAYDAY/7700 — BROADCAST.
*12. Emergency Landing Pattern — INTERCEPT.
*13. Gear and flaps — AS REQUIRED.
*14. Canopy — EMERGENCY OPEN.
*15. Battery switch — OFF.

In general aviation aircraft, checklists are also used, and they vary greatly depending upon the complexity of the machine. But a useful mnemonic is to follow the “ABCs”: “Aviate” (maintain flying speed) while looking for a “Best” place to land and using “Checklists” which generally include such things as applying carburetor heat and verifying fuel selector handle position to a tank that has gas in it. You’d be appalled, probably, to learn how many aircraft auger in because of fuel exhaustion. One of the first things an FAA mishap investigator will do when arriving at a crash scene is sniff for the telltale scent of 100LL – or its absence.

Sometimes an engine just punks out on you abruptly, and when that happens it’s a Very Bad Sign. Especially if you’ve done your pre-takeoff checklists and fuel management carefully. If you know she’s getting gas, and you know that the magnetos are turning – they will be if the prop is – and still the engine quits there’s probably very little you can do but choose your crash site as carefully as you can and hope to minimize the attendant damages.

Although I love my weekend gig initiating novices into the dark mysteries of air combat, there is one bit I love a little bit less. Montgomery Field sits atop a very densely populated urban center with few good places to put a sputterer down once you’ve broken earth, which is something I study on each time I put the spurs to her.

You have to have a considered plan before a Bad Thing happens, because if you don’t think it through at leisure you’ll have to cope not just with the aircraft emergency but also with the attendant helmet fire. I have come to the conclusion that if I lose the engine very shortly after take-off on Runway 28R, I ought to be able to glide in to the last 1000 feet or so of the intersecting Runway 23, which has a good apron in the overrun. But climbing through 800 feet or so the options gradually fall away. Too many have stalled and spun in attempting to stretch a glide in the “impossible turn” back towards the airport and there’s no really good place to set her down among the industrial and residential build-up surrounding the airport. About the best you can do is “land straight ahead” until you get above 1300 feet or so, and with all the surrounding power lines, trees, buildings and canyons, well: That’s going to leave a mark.

Highways are nearly everywhere else a good option, but SoCal drivers tend to go faster than a Varga glides with the engine out. Coming down out of the sky in front of highway traffic with the engine making no noise at all in rush hour traffic is a pretty good recipe for getting rear ended by a modern automobile constructed for collision safety in an airplane that was designed for no such thing.

Once we get out over the coast, the possibilities expand in every direction. A beach landing should be easily survivable, a water landing maybe just a trifle trickier. I worry just a little bit about whether the canopy retaining rods will keep the lid propped open when the machine comes to a complete stop in the ocean, but the airplane should float for at least a little while.

Yeah, I’m a little bit of a worrier, and my imagination can run away with me at times. I look at these characteristics as useful survival skills.

Sudden, total engine failures – absent fuel exhaustion – are relatively rare, although not unknown. More often the symptoms of an unhealthy engine creep in. Oil analysis might point to an engine that has started to “make metal.” Compression ratios start to drift out of bounds. Oil pressure or temperature readings spike, a cylinder head might run hotter than its peers. Carbon build up or an imperfect fuel/air mixture can lead to detonation which can in turn lead to thermal runaway as a piston goes out of round, chuffs against the cylinder wall or melts down completely.

N8275J and I have shared a little over 60 hours together over the course of the last eighteen months. Not a lot of time as such things go, but long enough, one weekend to the next, to become accustomed to her happy song. Her engine casing is not much to look at from the outside. No sandblasted radiator fins or powder coating for 75 Juliet – she’s a working airplane.

We had worked together quite happily on two unremarkable flights yesterday before her music suddenly changed 15 minutes into our third flight together. Having walked my guest pilot through some low altitude maneuvering prior to a demonstration dogfight, I took the controls and was climbing up to 2500 feet when I felt as much as heard some signal of her discontent. A low frequency rumble not unlike the sound you get when an engine is overleaned and trembling.

The mixture knob was pulled out a token half inch or so, so I placed it to full rich, just to see. No change. CHT was in limits, oil pressure and temperature were in the green. The rumble didn’t quite go away at reduced power, but the frequency changed. Probably nothing. A sticky valve perhaps. Perhaps a fouled plug. But, as I told my guest pilot in the back seat, something was “not quite right.”

I’ve read enough about the chaos that can swiftly come from order following a seemingly insignificant change in engine performance. The small vibration that becomes increasingly more severe until you throw a rod, engine oil all over the canopy, the whistling silence that follows. I toyed with the notion of selecting first the left and then the right magneto, to see if the problem could be isolated. But we were still flying, still putting out power. They could troubleshoot the mags on deck, so long as no new thing arose.

One of the “Cs” in the ABC checklist is “Commitment.” Make a plan and stick to it. We were going home, the flight would be cut short. Regrets.

“Not at all,” my guest pilot replied, before lapsing into a thoughtful but grateful silence. She was brave.

Earl the Pearl was a good wingman and offered useful advice while hovering around. I called Montgomery Tower to request a Class B clearance back to the field. The engine was running just a little rough I said, and I needed to climb into Lindberg’s airspace in case things went sideways. I needed room to glide, time to make considered choices. The beach didn’t look so welcoming as it had in my mind’s eye on pre-flight. Torrey Pines Golf Course was an option, too, although – having had the opportunity to walk its many contours – not a particularly attractive one.

“Do whatever you need to do,” the controller responded.

Miramar’s long runway beckoned under my left wing as I headed directly back to the field, still climbing. I confirmed that the Marine airfield was closed and that a downwind landing could be attempted without sucking up a departing FA-18 if it became necessary. The engine stuttered and stammered at full power, but we were still climbing and it didn’t appear to be getting any worse. Montgomery’s tower controller cleared me to land on Runway 28R, adding as an afterthought that 10L – the same runway in the opposite direction  – was closer if I wanted it.

“Say winds?” I asked.

“310 at 10,” he replied.

A long runway, but I’ve never favored landing downwind when I could avoid it. “I’ll stick with Two-Eight Right, for now.”

“Cleared to land,” he repeated.

The landing pattern was clear apart from our two airplanes. Tight abeam the airport at 3500 feet AGL, I pulled the throttle to idle, and the vibrations mostly went away. Mostly. The tower controller kept calling the winds every 15 seconds or so. Just for something to say, I think. Just trying to find some way to be helpful, with nothing left to do but wait. There can be a sometimes tense relationship between pilots and ATC at a busy airport under normal circumstances. They show a real grace and kindness though, when you need them to. I was grateful for their professionalism.

A long, continuous turn with just a little sideslip approaching base to burn off some excess speed and altitude. I blipped the throttle rolling out on final to ensure that the engine would still respond if called upon. It did, protesting slightly. Back to idle for one of the smoothest landings I’ve made in quite some time, right on the piano keys. Off at Golf taxiway, cleared across 28R, taxi to parking. Would any further assistance be required?

It would not.

The crash crew sounded almost disappointed.

Corporate was there to greet us as was Skip the mechanical magician. They’d heard our first call to Tower on the handheld VHF radio in the office and rushed out to the flight line in concern. Very relieved to see us taxi in. Refunds were offered to and accepted by our guest pilots.

“Sorry to have to cut it short,” I told our guests and the owner together. Probably nothing, but you know: Always better to be on the ground wishing one was in the air than vice-versa. Never to fret, all agreed. It was better to perform minor maintenance than a salvage operation.

Men were never meant to fly. Our frames are at once too sturdy to take to the skies, and too fragile to come down from them. But ever since the first man set his envious eyes upon a soaring bird, we have wanted to, and for millenia that has been enough to stoke our ambitions.

I’ve got a Citabria check-out and flight review on Monday, if the weather holds.

I’m very much looking forward to it.

PrecautionaryLandinkg

 

Happy Valentine’s Day to you!

 

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3 Comments

Filed under Best of Neptunus Lex, Carroll "Lex" LeFon, Carroll LeFon, Flying, Neptunus Lex

3 responses to “Precautionary Landing

  1. Pingback: Neptunus Lex: Stories on Naval Aviation and Safety | The Lexicans

  2. Pingback: Index – The Rest of Neptunus Lex | The Lexicans

  3. Pingback: The “Possible” Turn | The Lexicans

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