The most intricate preflight can still leave you with a feeling in the pit of your gut — did I miss something? Few of us are pilots and A&Ps, and even those of us who are have our off moments.
We look high and low under the cowl, up in the gear wells, through the cockpit, but some mechanical problems are presaged by symptoms that we don't recognize — but no matter. We find out about them soon enough. And we also find out how we do on the pop quiz — you bet your life — that follows.
But we can prepare for some of the more common mechanical heartaches (and gear aches, and engine aches) by thinking through how we would cope with each one.
Take Matt Tompkins' story. Tompkins faced a broken throttle linkage while on a test flight following an engine overhaul on a Cessna 172RG. Test flights as a rule cause significant gut wrenching (and warrant one of those detailed preflights mentioned before), and this one featured a plot twist.
"Upon arriving back in the local area, I pulled the throttle back to start my descent, and nothing happened," says Tompkins. "The engine was still producing maximum power with the throttle at idle. I tried moving the throttle from full in to full out and adjusted the throttle friction lock, but nothing helped. I circled the airport, staying within gliding distance of the runway. I had an idea of how I was going to land and wanted to get on the ground as soon as possible in case the problem escalated."
Tompkins planned to manage engine power the old-fashioned way, with the mixture control. But first he extended the gear to slow down from 120 knots to a better traffic pattern airspeed and help out with the descent. He stuck to standard procedure by entering the traffic pattern on a 45-degree leg to downwind. Then he changed things a bit by extending his downwind leg so that he could make a shallower descent and minimize airspeed buildup.
"When I turned base I started to lean out the mixture until the engine began to sputter," says Tompkins. "On final approach, while the engine was sputtering, I increased the angle of attack smoothly, holding it there for a few seconds to help bleed off airspeed enough to lower the first 10 degrees of flaps. When I got a little fast, I would lean out the mixture...and when I got a little slow, I would enrich the mixture to produce more power. After knowing I had the runway made I cut the engine and touched down."
Have you ever managed the power using the mixture control? It might be worth a try — at high altitude, over an airport, of course.
Oil — in all the wrong places
Doug Bowman sums up the thoughts reflected by many survivors of mechanical emergencies: "It coulda been better, and it coulda been worse."
Bowman was on a flight from Bend, Oregon, to his home in Tempe, Arizona, in his Van's Aircraft RV-6. He was flying at about 7,000 feet, which put him 3,000 feet above the terrain. "All of a sudden a triangle of oil appeared in the center of the windshield. Before I could think much about it, the oil quickly spread over the entire canopy — and it was an IFR flight in a VFR aircraft with a VFR-trained pilot."
Bowman was left with limited visibility through a small area on the lower-left windshield. He remembered that he had just passed over the runway at Sunriver, Oregon, (showing good awareness of his position) and he turned back toward it. "Sure enough, the approach could be made better by using a left traffic pattern [so I could see through] the small hole. As I turned final I realized that I would have the same visibility problem over the nose, but if I slipped the airplane, the small peek-hole became a way to line up with the runway." Just before touchdown, Bowman aimed straight down the runway, judging his landing using the edge of the pavement.
Oil had come through center of the prop, through the crankshaft oil plug on the Lycoming O-320 engine. Bowman had no prior indications of a problem: no high oil temp and good oil pressure. But he estimates he lost two quarts of oil in five minutes through that plug.
Training to do a traffic pattern in a standardized way paid off — even though he ended up with a nonstandard approach: "To make a good landing you start on downwind, and follow through with base leg and final approach," says Bowman. If you know what you and the aircraft are capable of, you can use all of the knowledge when you have to.
Electrical gremlins
Sometimes a little extra equipment makes all the difference. "My faithful [Cessna] Cardinal had a complete electrical failure on my way back home from a ski trip in northern Michigan," says Bill Artzberger. And it wasn't an academic problem — Artzberger was in instrument meteorological conditions at the time, in January's night skies. Fortunately, he had a flashlight mounted on his headset, and a larger one stowed in a seat-back pocket. Not to mention a handheld GPS and handheld transceiver.
"As I maintained my heading and altitude, I dug the radios out and turned them on. The GPS started up and began to acquire satellites. The handheld radio was dead. I had to find my spare package of batteries and swap them out in the dark. I'm sure by this time ATC [air traffic control] was wondering what was going on.
"After I got the handheld fired up I could hear ATC...but they could not hear me. I had forgotten about the external antenna jack I had installed for this type of emergency. I found the cable...all of a sudden, ATC could hear me quite well." Artzberger explained the situation and ATC gave him clearance to the nearby Pontiac VOR.
"They gave me a clearance for the VOR-A into Oakland/Troy Airport before I even arrived at the Pontiac VOR. I decided to shoot the approach using the GPS only, instead of switching my handheld radio to receive the VOR signal. I would not have been able to talk to, or hear, ATC at the same time.
"By holding careful headings — a challenge in a gusty wind — and monitoring the GPS, I was able to hold course fairly well, while pumping the gear down with one hand, of course. I broke through at 1,500 feet msl and landed on the slick runway with no lights or flaps."
As Artzberger reflects, "It is something we don't like to consider, but it can happen at any time." How long has it been since you shot a no-light, no-flap landing? Or navigated and communicated using your handheld equipment? Do you carry it on board every flight — with spare batteries?
Gear tricks
When you select the gear down, you expect a green light — go ahead, land, we have you covered. So failure of the gear serves up a surprise. Next quiz question: How is your systems knowledge?
Unless your gear failure happens in the soup, at the outer marker, in icing conditions, with fuel stores running low — the gear emergency isn't an urgency. As long as you have time in your tanks, you have time to sift through your options.
I spent some quality time with the pilot's operating handbook of a Beechcraft A36 Bonanza recently after failing to get light number three during a practice instrument approach into Winchester, Virginia. I had a safety pilot on board, and we got some altitude, headed back toward home (Frederick, Maryland), and cracked the book. We had at least three hours of gas on board, plenty of time — and some true motivation to read what Beechcraft wrote about its gear system many moons ago.
The emergency checklists offer some basic troubleshooting tips, but since we had the time, we also looked at the aircraft systems descriptions for common gotchas in the works.
From the cockpit we couldn't see the gear directly so we had to rely on the lights. The bulbs checked out OK. We tried recycling the gear and paid close attention to the aerodynamic clues sent out by gear extending into the slipstream. The second time resulted in a less-than-convincing nudge as the gear extended, and still no light on the left side.
We checked the breakers to see if any had popped — none had. After reading through the manual gear extension checklist, we completed it. The gear came down, locking into place on the last, hard turn of the crank. Three lights. Whew.
Five minutes later, the left main gear light went back out.
Ugh.
Just a few minutes from home, the light came back on. Great — but we didn't trust it.
We called unicom, and a lineman came out to watch our low pass. The gear looked down. However, this experiment, like a pregnancy test that comes back negative, can lie.
An emergency?
It generally takes 10 or 15 minutes to scramble the troops, so we made the decision to declare an emergency early, to give everyone time to get into position. While declaring an emergency gives you priority handling, and should cause other traffic at the airport to steer clear, we didn't count on it at our nontowered home field.
You consider a different set of options when one gear is partially extended, or one gear stays retracted with the others fully extended. Your best plan may be to retract the gear completely, if possible, and land gear up, rather than deal with asymmetrical gear — if you land with the gear that way it could easily cause the airplane to leave the runway or flip over. Anything that points to a loss of control is more likely to cause injury or worse, leaving you unable to exit the airplane on your own after coming to a stop.
Since we appeared to have three locked gear, but weren't sure of the left main, we decided to leave them down and compensate for it during touchdown.
If there's a crosswind, or a crosswind runway, set yourself up to take advantage of the natural slip that occurs when landing into a crosswind. We had a slight advantage, with the wind at 7 knots at a 30-degree angle to the long runway. So I set up the approach so that the crosswind was coming from the side that the positively downlocked gear was on. Since I would land on the upwind wheel in the crosswind, the weight of the airplane could stay on this gear as we rolled out. I kept the control deflection into the wind until the downwind wing came down on its own.
We had discussed stopping the prop by pulling the mixture and minimizing the chance of fire by selecting the fuel to the off position — but when I saw the four police cars, three fire trucks, two ambulances (one for each of us?), and the airport manager's Jeep waiting for us on the connecting taxiway, I forgot everything but the most important thing: Stay under control. And don't mess up in front of the crowd. (The crowd, by the way, was especially happy that their services weren't needed.)
The gear stayed locked; it had been locked all the time — a sticky switch was the culprit. But not knowing this, we called for a tow to the ramp: The stress of taxiing places varying sideloads on the gear and could have caused it to collapse if it wasn't fully locked. And if the prop had hit, the expense could be greater than a little scraped skin.
The last question on your quiz: What surprises might your airplane have for you today?
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