Monday, November 15, 2004

Oh, What a Lucky Man I Am, Part 3

Part One of this multi-part series of posts is here. Part Two is here.

With the technical basics covered, I can now write about the flight itself! As I said in the first post, bad weather and a chest cold had kept me out of the sky for about 5 weeks, which is a pretty long hiatus for me. Usually I fly every two or three weeks. When I was training, I was flying two or three days a week. I hadn’t flown in the Trinidad for 7 weeks, and this plane has a currency requirement at the flying club of 60 days. So as soon as I had some decent weather and felt well enough to fly, I had to go!

The day before this flight, we’d had some bad weather, with towering thunderstorm clouds, overcast skies, and even hail in some parts of the Bay Area. The weather forecast was for this weather to have moved to the south and east and for clear skies in Northern California. Here’s a satellite picture of the weather when I did my flight (click to enlarge):

Click to Zoom

You can see all the crud left over from the previous day’s weather system off to the east over Nevada, and lots of residual stratocumulus over the southern San Joaquin Valley and over the mountains south of San Francisco Bay. At this scale not every little cloud puff shows up. Some of the areas that look clear are actually covered with scattered little clouds. Offshore, on the left side of the image, you can see the sweeping arc of the next frontal system hundreds of miles out to sea. The only effect this had on me was to put some pretty cirrus clouds into the sky above me.

Before I headed out for the airport, I thought there’d be less stratocumulus clouds in the sky than there actually were. My goal was to head off to the east and fly around the open mountainous country out behind Mt. Hamilton. However, on the drive out to the airport, it was obvious that the lower atmosphere still had a lot of moisture from the previous day’s storm. There was a light haze, and the surrounding hills were covered with low, ragged, puffy clouds. Looking to the east, it looked like the way through Sunol Pass was almost blocked, with the cloud bases just touching 2000-foot high Monument Peak. The clouds looked like they were about 1500 feet thick. Looking to the South, the top of Black Mountain was in a cloud, and clouds were distributed over the whole length of Skyline Ridge. There weren’t many clouds over the Bay plain itself. Since the Bay Area is ringed by mountains, and since the San Francisco airport airspace lies on top of it like a lid, this meant that it would not be particularly easy to just go up and have a hassle free joyride. This is doable with a 3500-foot ceiling, but not under 2500 foot cloud bases. So I figured, I’d just stay in the airport traffic pattern and practice takeoffs and landings.

Walking into the club, I got the schedule book and keys for the airplane and had a brief chat with my flight instructor, who was between flights. I noticed that I still had a tinge of that surreal “sick” feeling from my chest cold (you know, where things look a bit like you’re looking through a fisheye lens, and there’s something a bit “off”). I decided I’d go out to the plane and do the preflight inspection and see if I could get my mind into it and feel normal enough to fly (it seemed pretty unlikely that I wouldn’t be able to).

When you haven’t flown in awhile you’re definitely a bit apprehensive. “Do I still remember how to do this?” But walking out to the flight line carrying your flight bag, those circuits in your mind start to reactivate. Ah, surrounded by airplanes again! I pass my old friend Bonanza 828R and continue another couple of hundred yards to Delta Row, where the Trinidad is tied down. I always take my time getting a plane ready to fly. It gives my memory a chance to put me back into “pilot mode”.

The first job is to open the gull wing doors on both sides of the plane, take all the glare shields out of the windows, and check the tachometer hours reading against the schedule book. Next I step up onto the left wing and climb into the pilot’s seat. I take a good look at the panel, which I haven’t seen in almost two months, and spend a few minutes gazing at and studying each of the gauges, thinking about how they will come into play during the flight. It all comes back to me. I’ve got over 100 hours in this type. I am a Trinidad pilot! Even though I haven’t looked at or thought about this panel in 7 weeks, I am intimately familiar with it. It is second nature to me.

I turn on the master electrical switch and turn on the avionics. I check each of the two COMM radios by tuning them to the Palo Alto Tower information recording (this is called ATIS), and listening over the speakers. The ATIS recording gives the wind direction and velocity, sky condition (in this case “2500 scattered”, which confirms for me that the bottoms of the puff ball clouds are at 2500 feet), visibility, temperature, altimeter setting, and runway in use. I next check the NAV radios by tuning them to the frequency for the Woodside VOR beacon, checking the Morse Code identifier for the beacon, and an indication that I am on the beacon’s 046 degree radial. The beacon itself is about 9 miles southwest of me at the crest of the Santa Cruz Mountains. After this, I check that the GPS database is current. The avionics having checked out, I flip the avionics power switch back to “off”.

Next, I check a few other electrical items. I take a look at the fuel gauges (not that I trust those things), and toggle the flap switch to full extended, watching as the flaps lower on either side of me. Next I turn on all the switches for the exterior lights on the plane, as well as the heater for the pitot tube (the pitot tube is a little device under the left wing that measures the airspeed). Climbing out of the cockpit I walk around the plane, feel that the pitot tube is heating up, and that all lights are working. I also check the stall-warning switch, which is controlled by a little vane on the leading edge of the left wing. When the wing gets within a couple of degrees of the stalling angle of attack, the airflow gets to the other side of the vane and pushes it up. This closes a switch, which causes a buzzer to go off in the cockpit. If I’m a pilot and I hear the stall warning go off unexpectedly, I have the instinctive reaction of pushing the yoke forward and cranking in more power to prevent a stall. It turns out there’s something wrong with the switch or the buzzer, so I won’t be hearing any stall warnings today (no major problem, I’m not foreshadowing anything here). I note on the “squawk sheet” in the schedule book that this needs to be looked at.

I turn all of the electrical switches back off and do the external inspection of the plane. This includes checking the overall condition of the plane, checking the control surfaces, untying all the tie-down ropes, checking the tire condition, checking the fuel levels and examining fuel samples, checking the oil, wiping the rainwater off the windscreen, and checking the micro switches of the landing gear system (these control the gear indicator lights and tell the control unit when the gear are fully retracted). During all of this, I reflect that the plane is still just a 2500-pound, inert, inanimate object. Well that’s about to change!

I get all of the items that I’ll need for this flight out of my flight bag and place them in the right seat of the plane. My noise-canceling headset (It’s very noisy in these planes; a headset saves your hearing, and allows you to listen to the radio and your passengers. It also has a boom mike for talking over the radio or to passengers wearing their own headset). My kneeboard, which holds the Trinidad checklist, and a flight information sheet where I will copy down ATIS information. A pen. A kitchen timer which I use to countdown 30 minute intervals for switching fuel tanks. A San Francisco terminal area chart, which I fold so that the Palo Alto and coast areas are handy. Then I toss the flight bag into the back seat, close the passenger gull wing door, and climb in.

I go over the preflight checklist to make sure I’ve covered every item. Checklists are crucial. Airline crews do not make a single move without consulting a checklist, and it took me a while during my training to force myself to adhere to one and not go by memory. It turns out I forgot to check the fuel vents, so I climb back out and make sure they’re okay. All right! Time to spend some money! So far this flight hasn’t cost me anything. The rental charge only accrues when the engine is running. I put on my seatbelt, close my gull wing door, and flip open the little ventilation window so I don’t suffocate (I exaggerate) in there while on the ground.

This inert machine is about to come to life! Following the checklist, I set the parking brake, turn on the master switch and prime the engine. The big, fuel injected engine needs to have some liquid fuel pre-squirted at the cylinder intake valves when the engine is cold. This allows enough fuel vapor to be available at the cold temperature. The procedure is to crack the throttle lever open about a quarter inch, turn on the electrical boost pump (which results in a high-pitched whine), and move the mixture control to full forward, waiting for a stabilized flow indication on the fuel flow gauge. Usually I wait a bit and nothing happens until I crack the throttle open a little more. After the flow indication settles down for a second, I pull the mixture knob back, turn off the boost pump, and reset the throttle to one-quarter inch open. This is it! I note the current time on my information sheet. I’m allowed to log the entire time between engine start and engine shutdown in my pilot log book. I shout, “Clear!” out of the ventilation window, giving anyone standing in the propeller arc a final chance to live. I put the key in the ignition, turn it full to the right and push.

In order to save weight, the starters on these airplanes are not very powerful. The engine has pretty high compression, as well as cold oil in it, so the propeller doesn’t just spin up, but does more of a choppy, slow chunk, chunk, chunk motion. The first chunk is the slowest because the oil hasn’t started moving yet. On about the fifth chunk, the engine fires. I get one hand on the throttle and the other on the mixture control, which I ease all the way forward, while tweaking the throttle to achieve 1000 RPM. Once the engine is running smoothly I bring the mixture control back about 20%, because a full rich setting can foul the spark plugs at low power. Checking the oil pressure, I turn on the alternator switch and make sure the battery is charging. Then I flip on the avionics switch and put on my headset. The physical headset itself saves my ears from all the high frequency cacophony of the engine, and turning on the Active Noise Reduction cuts out the low skull-pounding frequencies (not that the engine is so loud at idle). “Check, check, check”, I say as I tweak the intercom volume, adjust the squelch, and copy down the ATIS information (each hourly recording has a sequence letter associated with it, in this case ‘N’, or in military/aviation speak, ‘November’). Looking at the checklist, I retract the flaps, and release the parking brake (I’m keeping the brakes applied with my feet by pressing on the top of the rudder pedals).

Time for the first radio call! I push the transmit switch on my yoke. “Palo Alto ground, Trinidad Five-Two-Juliet-Gulf, Delta Row, taxi 31 for right closed traffic with November.” 31 is the runway in use. The number is derived from the magnetic heading of the runway. The Palo Alto runway is laid out with a magnetic heading of 306 degrees. Round to the nearest ten and drop the final zero, and we get 31. This is the number painted on the end of the runway. “Trinidad Five-Two-Juliet-Gulf, taxi 31”, replies the tower (from now on, I’m going to refer to the plane as 52JG, but over the radio I’m really saying “Five-Two-Juliet-Gulf”, all right?). Right closed traffic means I’ll be flying the rectangular pattern over the Bay and practicing takeoffs and landings.

Keeping my feet on the brakes, I crank the throttle open to 1500 RPM. I release the brakes and as the plane starts to move out of its tie-down spot, I tap on each brake separately to make sure I’ve got the expected differential action. When I’m steering on the ground I push on the appropriate rudder pedal to make the nose wheel swivel left or right, and if I need to make a tighter turn, I can also use differential braking. As I pull out of the space and make a left turn onto the taxiway, I’m checking the main flight instruments. The turn coordinator should be tilting the wings on the miniature airplane indicator to the inside of the turn, while the ball moves to the outside of the turn, the compass and heading indicator should be swinging around and showing my changing magnetic heading, the attitude indicator (or artificial horizon), should show me level, the altimeter should show me at airport elevation, the vertical speed indicator should read zero, and the airspeed indicator should read zero.

The taxiways all have yellow lines running down their centers, and it is my job to keep the nose wheel on this line. This keeps my wings from hitting parked aircraft while I’m heading to the runway, but I’m always keeping an eye out. A plane is a lot wider than a car! In the early part of my training, it was very tough to steer with my feet. I’d be weaving all over the place, trying to use the yoke as a steering wheel…

I follow the yellow line out to one of the run-up spots adjacent to the runway entrance. I stop at the yellow crossbar and set the parking brake again (but keeping my feet on the brakes). Now I am facing perpendicular to the runway. Here I will perform the run-up checklist, in which (after checking that the control surfaces all move correctly in response to moving the yoke) I will check the airplane systems at partial engine power. I push the mixture control to full rich, and open the throttle to 2000 RPM. At the 1500-RPM setting that I used to start taxiing, I was at about 17% power. At 2000 RPM, I’m at about 40% power (100 hp), which is a decent amount of power. So the plane is shaking a little bit from all the thrust coming from the now fairly loud engine. The first task is to exercise the prop governor in order to check for proper operation and circulate warm oil through it. I pull all the way back on the blue lever until, with a whooshing sound and a descending roar from the engine the RPM drops to 1500 RPM. I push the lever all the way forward to bring the RPM back up and then do the sequence a second time. When I pull the lever back, this causes the governor to turn the prop blades so that the broad flat part of the back of blade turns toward the direction of rotation of the prop. This causes the air resistance on the blade to increase, resulting in the whooshing drop of engine speed.

Next I check the magnetos. Unlike a car, an aircraft engine has a fully self-contained ignition system, which doesn’t require a battery or functioning electrical system. It’s a safety thing. For redundancy and increased efficiency and power, each cylinder has two sparkplugs instead of just one, with one plug fired by the left magneto, and the other fired by the right magneto. A magneto is a self contained generator and spark producer which is driven directly by the engine. In the magneto check, I turn the ignition key to short out each magneto in turn. This results in about a 100-RPM power drop. If there were something wrong with one of the magnetos, the engine would quit when I turn the key to short out the opposite magneto. Sometimes the plugs get fouled by running at idle with too rich a mixture. Then the RPM will drop by a couple of hundred RPM and the engine will run rough on that magneto. It’s possible to fix this by switching to both magnetos, cranking up to 2200 RPM, and leaning the mixture in order to “burn off the carbon”.

After the magneto check, I check the vacuum gauge to make sure there is enough suction to power the gyroscopic instruments (i.e. the attitude indicator), and then bring the power back down to idle again.

Okay, finally, this bird is ready to fly! Actually it’s only been about 10 minutes since I started the engine, and maybe 35 minutes since I walked out to the plane. The pre-takeoff checklist has me lowering 10 degrees of flaps, activating the transponder so I will show up on air traffic control (ATC) radar, setting rudder and pitch trim, making sure the doors and ventilation window are closed, turning on the fuel boost pump, and releasing the parking brake. “Palo Alto tower, Trinidad 52JG is ready for takeoff, 31”. “Trinidad 52JG, pull up and hold short.” There are other planes in the pattern, including a couple that will be landing before the tower lets me take off. I can see them stacked up along the final approach path. I taxi up to the hold bars at the entrance to the runway, with the plane facing out a little toward the final approach course. I want to be able to see if anyone is coming in when the tower tells me to get onto the runway. It is legally my responsibility even if the tower makes a mistake.

It will be a couple of minutes, so I pop open the ventilation window again. At this point, I am filled with a serene calm. I figure I’ve done more than a thousand takeoffs in the last three years, so I’m not pumped up with adrenaline. I look at the takeoff checklist and mentally rehearse what I’m about to do. Once the Trinidad gets moving, things happen fast. The tower tells a third plane in the pattern to extend his downwind, “to allow one departure, a Trinidad.” After the second plane flies across the runway threshold, I close the ventilation window and push the mixture control to full rich. “Trinidad 52JG, position and hold.” I cross the hold bars and roll out onto the runway, using differential braking to get myself lined up with the centerline. I have the whole runway stretched out ahead of me. The second plane that landed is still rolling, so I have a few seconds before I get my takeoff clearance.

You know, right now I’m getting excited just writing about this!

Just before the other plane turns off the runway, I make sure the blue lever and the red lever are full forward, and I crank the throttle up to 2200 RPM (about 55% power). The plane is straining against the brakes. I check the oil pressure, oil temperature, and fuel flow gauges. I tell myself, “rotate at 68 knots, gear up.” I look at the windsock along the right edge if the runway. There is a bit of a right crosswind, so I turn the yoke halfway to the right to compensate.

Although I did three times through the pattern before heading to the coast, I’m going to describe my final takeoff. After three really nice landings and feeling solidly confident, I at least wanted to fly toward the hills and check the cloud situation (I wasn’t expecting to make it to the coast).

“52JG, you are cleared for takeoff.”

“52JG, rolling.”

I take my feet off the brakes and the plane surges ahead. Over the next couple of seconds I smoothly push the throttle lever all the way forward. Single engine propeller planes have a strong tendency to veer hard to the left at takeoff power (for various reasons), so as I increase the power, I am pushing harder and harder on the right rudder pedal to keep the plane rolling straight down the runway centerline (my first training flight featured a takeoff that had me careening wildly down the runway; it takes awhile to get a feel for rudder control). The engine at full power is just monstrous (this ain’t no trainer airplane). I glance at the tachometer and the MP gauge to make sure I’ve got 2700 RPM and 29 inches. I glance at the airspeed indicator to make sure the speed is coming up. If anything looked or felt wrong, I’d pull the throttle closed and abort the takeoff. If I had any spare attention to take notice, I’d feel the acceleration pushing me back in my seat, but most of my attention is in looking at the runway with the occasional quick glance at the airspeed indicator.

During my first 30 hours of flight training I suffered from an awful rudder pedal coordination problem. When I was in the air, I’d work the pedals correctly. When I was taxiing, I’d work them correctly. But when I was hurtling along the ground during the takeoff roll, my ski reflexes would kick in. When you’re skiing, you push with the right foot to turn left. When you’re taking off, it’s the opposite. Imagine my frustration. Anyway…

As the plane speeds up and the airflow increases over the elevator and ailerons, the control feel on the yoke firms up, and any deflection of the yoke has a bigger effect. For this reason, as the plane accelerates, I turn the yoke more towards neutral to maintain my crosswind correction. At 68 knots, I firmly and smoothly pull back on the yoke. This lifts the nose wheel of the plane off the runway and pitches the plane up into the climb attitude. As discussed in part 2, this increases the angle of attack, and therefore the lift that the wings are generating. The plane continues to accelerate in this position for another second or two, and then to me, it feels like a giant wedge of air hits the bottom of the plane, suddenly boosting it off the runway. In my peripheral vision I can see the ground quickly dropping away from me on all sides (at this point I don’t have a lot of forward visibility of the ground due to the takeoff attitude). “Gear up!” I say, pulling the white “donut” of the gear switch toward me to disengage the safety lock and moving the switch to the up position. I keep my hand on the switch to remember to check the gear lights once the gear have come up.

Checking the airspeed indicator I see that I am a little slow, so I lower the nose a bit by pushing forward on the yoke. I want to nail 95 knots, which I quickly do. The vertical speed indicator is showing me climbing at better than 1000 feet per minute. I glance at the gear lights which are all off now, and execute a 10 degree right turn to keep me from over flying the neighborhoods straight out past the runway. At 1000 feet altitude, I push the yoke forward a bit to establish 100 knots, pull the throttle back to 25 inches, and pull the prop control back to 2500 RPM. The engine quiets down considerably. I also retract the flaps, which causes the plane drop a little and then suddenly feel much more slippery through the air. When I reach the road that goes to the Dumbarton Bridge, I start a 90-degree turn to the left, which has me flying toward downtown Palo Alto, and Skyline Ridge. As I pass 1500 feet, the tower says, “52JG, frequency change approved. Have a good flight.” “52JG, good day.” I am now out of the Palo Alto airport airspace and am no longer much concern to the tower.

At 2000 feet I level off. I’m going to go with a low cruise power setting because it is often bumpy at low altitude near a ridge, and it is generally bumpy flying under puffy clouds. Also, the lower cruise speed lets me do tighter maneuvers, if necessary. I bring the MP down to 22 inches with the throttle and bring the RPM down to 2300 with the prop control. I also lean the mixture (there’s a special gauge that helps me do this precisely), and set the rudder trim for cruise. I put the San Francisco VOR beacon identifier into the GPS so I can measure my distance from it. I can then use my chart to stay out of their airspace (basically, the farther away I am, the higher I can go).

Now my workload has decreased considerably. All I need to do is hold my 2000-foot altitude (an automatic reflex for me), steer the plane, and not accidentally “bust” San Francisco’s airspace.

To be continued…

Update: Part 4 of the series is here.

1 comment:

Frances said...

Great storytelling. Thanks. I felt as if I was there. Now, what is a medicine ball? (from Part 2 I think)

You ought to consider teaching. You make things so understandable!

Kudos, Matt.