Approach Energy Management

Its finally here. I've met the multi-engine time insurance requirements.  I have what I needed to upgrade to full fledged Captain on the Navajo, so I finally get my upgrade.  Yesterday we did my Captain check ride.  Its wasn't a big deal really, did some aerial work to start off - steep turns, climbing/descending turns, slow flight, stalls.  The usual.  The Navajo is easily the most stable aircraft I've flown.  It was smooth air during our flight, and when I was demonstrating some rate one turns (standard turn of 3°/second) with the airplane properly trimmed I was able to roll into the turn, establish the attitude, and then completely remove my hands from the controls!  The Navajo would maintain a perfectly stabilized bank all on its own and carry itself all the way through the turn without any need for further adjustment.  I've never seen an airplane stable enough to be able to do that.  It makes me look good!

After the air work we reviewed our emergency procedures.  That took us all of an hour.  The ops manual mandates 3 hrs of flight time for an initial PCC (Pilot Competency Check), so we took the time to practice some IFR approaches just for the fun of it.  It was fun to get back into that world again for a little bit and shake off the rust.  The Navajo, being so stable, makes a great platform for IFR practice.  It was also good to really get some practice fine tuning my approach skills in the Navajo.

Whenever I set up my final descents to land, either VFR or IFR I try to plan the approaches in such a way that I only ever need to reduce power, never add more as the approach progresses.  Its not really critical, but it is a lot easier on the turbos, allowing them to spool down gradually with progressively lower power settings.  That and its a good challenge to keep my skills sharp.  It takes planning, judgement and a good knowledge of what power settings the airplane needs so as to not have to increase the power at any point during the approach.

Normally, at the beginning of the descent to land, you start off with the airplane in a clean configuration (flaps & landing gear up) and a cruise power setting (high airspeed), but by short final you should have full flaps set, the landing gear down, and a low power setting sufficient to provide an appropriate descent angle of around 3° and nice slow approach speed.  Its easy enough to set the power to set up your approach angle and  airspeed, but if you set the power to give you the proper descent angle and airspeed BEFORE you have the flaps and gear down, you're going to have to ADD power again later when you lower the landing gear or flaps to account for the increased drag.  With an equal power setting, flaps and gear will always either increase your descent angle (if you maintain the same airspeed), or it will decrease your airspeed (if you maintain the same descent angle).  A stable approach should always have a constant descent angle, so we should strive for that.


The first thing they teach you when you first start flying an airplane is that on approach, power controls the descent angle, attitude (the angle of the nose to the horizon) controls airspeed.  This means that if the current descent angle is going to bring you short of the runway, rather then pulling back and raising the nose (the natural inclination) you need to add power.  Pulling back will reduce your airspeed, so you should only pull back if you need to slow the airspeed, otherwise the potential exists for a stall.  Alternatively if you're going to land long, rather than pushing forward, which will just increase your airspeed and still cause you land long, you must reduce the power.  The concept of "Attitude controls airspeed, power controls glide slope" methodology works quite well for teaching purposes.  It keeps things simple for new pilots who still have to use the cognitive part of their brain to control their approach.  As proficiency increases you learn to do both (control attitude and power) simultaneously as needed to achieve the right approach and right airspeed, and it becomes second nature.  Using power to control glideslope and attitude to control airspeed never ceases to be a safe method for flying an approach even for experience pilots, but it can be sloppy in the sense that it requires constant power adjustments, and small increases in power each time landing gear and flaps are lowered.


So as professional pilots we can take it one step further and rather than just manage our airspeed and approach angle as separate variables, we can focus on energy management as an entire system.  Lowering the flaps and landing gear are removing energy from the system in the form of extra drag, so rather than having to replace it with more energy by adding power, we can plan for it in advance by already having extra energy in the system.  The key to holding extra energy is to do so in the form of carrying extra airspeed at the beginning of our approach.


Now rather than adding power every time we lower the next notch of flaps or landing gear, we want to start our approach with a higher airspeed then what we want to end up with on short final.  In the Navajo for example, or short final we want a stable approach at 120 mph, with full flaps and landing gear down.  That means when we start our approach with a clean configuration (flaps/gear up), we should start with a higher airspeed, perhaps around 150 mph.  In this way each time we introduce more drag into the system by lower gear or flaps, rather than countering the energy loss by adding power, we use the extra drag to our advantage by allowing it to slow us down.  Hopefully if our judgements are correct, by time we have all flaps and landing gear lowered, we're at a stable 120 mph, having never touched the power since we first started our descent.

In this way we're actually simplifying our approach by allowing each new drag element to slow us down rather than adding the extra steps of trying to slow down at the beginning by pulling the power WAY back, and then compensating for it later when we add more drag.  When done properly the engines are happy because they have received consistent inputs, any traffic behind us is happy because we didn't hold them up by dragging our way all the way down the approach at a slow airspeed, and we're happy because our workload is less and we're demonstrating a mastery of our aircraft.

Full Bore

The last 4 days have been a whirlwind.  We had a 4000 line km deadline to meet with the client by June 21st, and we arrived onsite on the 15th.  Normally it takes about a week to get good weather and a good calibration flight down, and set up our other ground equipment before we're off to the races surveying.  On top of that, 4000 line km is roughly 4 full days of flying.  Well, we lucked out with good weather, a good calibration flight on the first try, and we've been going full bore since.  We finished over 4000 line km with a day to spare.  That's gotta be some kind of record!  Almost 20 hrs flight time in two days, lol.

Today was spent revving back a little bit as our inspection is coming due, and we have a lot of catchup with paperwork and setting up the crew house that we plan on moving in to.  Tomorrow we'll spend some time training - I have my Captain upgrade to get done, and then I'll be renewing my Co-Captain's annual training. Then airplane inspection.  Much to be done.

As for the flying, its not nearly as interesting as France or Ireland, or even northern Canada.  Offshore is just... water.  We haven't even seen any boats or whales yet.  Oh well, you gotta take the good with the bad, at least I'll be logging multi-PIC time soon.

Number 10 to Land

Toronto Buttonville.  If its not the busiest general aviation airport in Canada I would be surprised.  Its my turn to sit left seat in the Navajo, we're returning to home base from Ottawa to fix some more technical issues.  We've had a really terrible string of bad luck lately.  I've got the ATIS and make my 10 mile call as requested by ATC.  (ATIS - Air Traffic Information Service, an automated radio service to tell aircraft pertinent details for departure and arrivals, such as winds, runway in use, etc.).

"Golf Sierra Xray is 10 miles east, 2000 ft."

Its a beautifully calm, blue skied evening and there are at least 4 airplanes doing touch and goes and another 6, including us inbound to land.  The controller is making radio calls nearly continuously but still sounds totally calm, maybe even bored.  I'm impressed.

"Golf Sierra Xray  you're gonna have to pull it right back, right now you're about number 10 for the field.  Call me 3 miles out."

Wow poor guy, 10 airplanes and with so little airspace to work with.  Two more airplanes report inbound.  Make that 12 total.

I pull the two power levers in my hand way back to 23" Manifold Pressure, and we slow down to 120 mph, something a little closer to what a Cessna 172 would be cruising at.  Normally we don't slow down this much until we turn onto our final approach to land.  I watch the miles tick down as we creep along closer to the airport.  I'm anticipating joining the circuit on a right base for runway 33, and both of us in the cockpit have our eyes out side looking for the other 9 airplanes around us.  The radio calls are still going rapid fire, and our portable traffic awareness system is also beeping with almost as much frequency.

I make my 3 mile position report.  When the radio is this saturated, it can be difficult to jump in and make your required reports without stepping on someone else.

"Golf Sierra Xray turn right to come overhead the field, I'm going to bring you in on a left downwind.  You're going to be following a Cessna 172 in the downwind."

I make a shallow right turn to head over the airport instead of setting up for a right base, and we meander our way over top of the field.  At 120 mph the controls are no longer the crisp responsive feel that they are at normal cruise speeds.  With this much less airflow the airplane feels more like a lumbering beast, and the earth is creeping by in slow motion, but this is a good pace to fit in with the rest of the traffic and gives us enough time to try to spot everyone else up here with us.

We try to find our traffic ahead of us, and I spot a Cessna turning base, but that's a different one than the one we're supposed to be following.  The controller is extending everyone's downwind legs to make room for everybody.  We're way south of the airport now, heading towards the east of Toronto.  We end up turning base, and then final, close in behind a Piper Cheyenne - too close actually.  At this spacing he won't have time to clear the runway before we're ready to land.  Even though we're still 4 miles back I drop all the flaps and lower the landing gear to slow down even further.  I'm riding blue line, 112 mph - the slowest safe speed we can fly.  The Cheyenne slowly pulls away from us.  It looks like we might be all right, but we still prepare for the possibility of an overshoot if the Cheyenne can't clear the runway in time for us to land.  Mixtures rich, propellers to high RPM.  We're short final, the Cheyenne is down and turning off the runway just in time.  We're cleared to land.

I touch down smoothly in the calm evening air and am stopped in time to exit onto the inactive cross runway.  Taxi in, shut down.  That was fun!

Delays... A day in the life

This last week we've been struggling here at home base to get our survey equipment for the navajo within spec.  Part of the reason is the installation of new equipment for the contract, but also the contract requirements are unusually tight for this particular client.

In order for the magnetic sensors on the wings and tail to accurately measure the earth, any magnetic components on the aircraft, especially near the sensors must be demagnetized.  Hardware like nuts and bolts can be tricky because they have a tendency to magnetize themselves over time, so we have to go hunting for them by running a compass past and seeing if it swings towards its.  If we find a nut or bolt or screw that is magnetic, we'll replace it if we can, or run it through a degausser, which is a machine that electrically scrambles the polarity of the particles in the hardware and demagnetizes it.  The degausser is far from perfect - sometimes it works, other times it ends up magnetizing the hardware even more.  Its tedious and time consuming work.

Hopefully soon we'll be on our way.  A couple days ago I planned out our route to Newfoundland.  I had a total of 5 VNCs (aviation maps) all laid out on the floor and lined up.  On the map itself our route measures over 10 ft long - a total of about 900 nautical miles.  That's a long trip!  It will be fun to fly all the way out east.

In the mean time we're stuck checking out of our hotel every morning with the hope of being on our way, only to have to take the walk of shame in the evening and check back in.  The hotel customer service manager always gets a laugh out of this.  It's not an uncommon scenario for us actually, it happens fairly often as there are always some sort of delays in trying to get off to a new job. When we check out the hotel staff are never quite sure whether to wish us well on our way, or to say "see you soon".  Such is the reality when you combine the somewhat unrefined technology field of airborne geophysics with the equally unreliable industry of general aviation.  It's impossible to make hard and fast plans when weather, broken airplanes, or finicky survey equipment are a part of the equation.

Just a day in the life...

Here We Go Again, and Off-shore Training

Its been a while since I've written.  After we finished France I got the winter off from flying.  Bought a house, renovated said house, moved into house.  Spent time with friends and family.  Life is good.  Back to flying.

We've since finished a 6 week job in Ireland.  Other than being threatened to get shot down by a wacked out lady, being accused of flying "WAY too low" by some local pilots who know nothing about survey flying, and having numerous weather delays from Irish weather, the job went pretty well.  Ireland itself was pretty cool though.  It lives up to most of its stereotypes... I thought so at least.

As of the end of Ireland I'm still 12 flight hours short of the insurance minimums to be Captain on the Navajo, but that will be remedied shortly on our next job.  Since Ireland I've had a couple weeks off, and am gearing up  for shipping out to Newfoundland for our next contract.  This job is going to be an offshore survey, so there's some special safety precautions that we need to take.  Neither myself nor the other pilot going with me has any time flying offshore survey, but our Chief Pilot has.  So in addition to spending some time at the office here getting things ready to go, we've spent some time talking to him to get some pointers and advice on offshore flying.

As part of our Maritime survival equipment, we carry onboard an inflatable life raft, but also we will be wearing Immersion Survival Suits.  These are basically a one piece foam insulated jump suits that cover us head to toe to keep us warm and dry in the event that we have to ditch into the Atlantic Ocean.  We'll be wearing them full time throughout all our flights offshore.  At least we'll have our feet in them and will keep the top half unzipped around our waste.  Its quite the monstrosity to put on and wear!  Its basically impossible to fly an airplane while wearing them fully.  They completely mummify you, including your hands and a rubberised hood that covers everything but your face.  For your hands, imagine Pooh Bear.  You can't do much.  In fact its quite the feat to even get out of your seat and get the aircraft door open with the suit on, so that's what we practised today.  We intend to practise some more evacuation drills once we arrive onsite.  They say when you ditch an aircraft you have 30 seconds between the time you crash and when the cabin has filled with water and panic sets in, so that will be our goal:  Get our arms in and zip up the top half of our immersion suit and evacuate the aircraft in less than thirty seconds.