April 30, 2007
Many years ago I flew a turbocharged Beech Bonanza from Wichita, Kan., to Springfield, Mo., and return. The roughly one-hour flight to Springfield was uneventful above a building base of puffy cumulus clouds. I dropped off a passenger at his airplane, the mission for our flight, and took off again for home.
On departure the skies around Springfield were filling in so I filed for and received an instrument clearance. Traffic in the terminal area was busier than usual, too, so my workload was fairly high as I transitioned to instrument flight while maneuvering around the biggest clouds and working with ATC and everyone else on frequency trying to do the same. Soon I settled into cruise at 8000 feet, still deviating a little here and there to stay out of ice and the beginnings of a line of storms.
I was cruising level for about 20 minutes when I noticed I'd forgotten something. The Bonanza's mixture control was still in the full rich position. This was the proper position for climbs in the A36TC I was flying, but in cruise it meant I was burning about 24 gallons per hour -- one-third again more than the flow called out in the Pilot's Operating Handbook. It was not critical on this particular flight; the A36TC I was flying had 74 gallons of usable fuel when I left Wichita and I'd burned about 25 total getting to Springfield (including takeoff and climb) so I still had 49 gallons on board for the second takeoff. Even at full rich in cruise that gave me about two hours' fuel for the one-hour trip home. But if I was flying to Denver or Amarillo or some other point further west, my mistake would have caused me to run out of fuel en route even though the POH said I had plenty to make it with a reserve.
How could I have caught my error sooner? That particular flight caused me to become a big proponent of checklists and flows.
|Instructor and student
Think back to your very first flying lesson. No doubt you walked through a preflight inspection with your instructor, then settled into the left (or front) seat for the first time. Though it seems so simple to you now, you were amazed at the complexity of the controls and instruments and radios in that little trainer. You were probably relieved when your instructor handed you a small book or a laminated card that contained everything you needed to do, in sequential order, to make sense out of this chaos and bring a seemingly complex machine to come to life and then to fly at your command.
Read a step, do a step ... that's probably how you learned to use this checklist. This is an effective way to learn the proper order of actions, but there are two very common errors associated with this type of checklist use:
- Using the checklist as the instigator of your actions makes it very cumbersome to use, especially once in the air.
- The checklist is seen as a temporary crutch to be overcome, then discarded once you "learn to fly".
In short, most instructors teach checklists as a "do list" -- do this, so that happens -- instead of what it really is designed for, to check you haven't forgotten something as a result of inexperience or workload. Using printed cards as a "do" list is a sure fire way to stop using them at all.
Why Checklists are Important
The Boeing B-17 was one of the most successful warplanes in all history. Thousands upon thousands left massive defense factories for combat overseas as well as the vital combat-crew training role in the Zone of the Interior (the Army's WWII term for the continental U.S.). The Flying Fortress carried America's might to its enemies in the only way possible until troops or ships could move in. The B-17 also developed a deserved reputation for saving its crewmembers by absorbing the worst that could be thrown against it and, more often than not, still making it home. But the entire Boeing B-17 project was nearly halted before the war ever began. And it was because of a checklist.
The U.S. military began requiring its pilots to use checklists in the 1930s. Airplanes were becoming very complex and it was difficult for pilots to train quickly enough to keep pace with progress. With a possible war looming, Boeing responded to an Army proposal for a bomber with the Model 299, a four-engine behemoth the Air Corps designated the YB-17 ("Y" for prototype). In isolationist America, the big Boeing was under intense public criticism and scrutiny when one of the YBs crashed on takeoff from Wright Field near Dayton, Ohio, the Army's primary engineering test base. The professional test crew had forgotten to disconnect the tail's gust lock before takeoff. The big, silver ship was uncontrollable, crashed into a hill off the end of the runway, and was completely consumed by fire. The crew was lost but somehow, politically, the B-17 program survived. The Army immediately began requiring the use of checklists for all pilots in all phases of flight.
Why They're Important to You
If a professional flight test crew can fatally forget something as simple as a mechanical gust lock, workload and pressure to "go" also can cause everyday pilots like us to sometimes forget critical items.
Consider that some of the most common accidents result when something simple is forgotten. Pilots run out of fuel because they forget to lean the mixture or switch fuel tanks when needed. They crash on takeoff because the trim is set incorrectly or flaps are used (or not used) as needed, or they forget to latch a door, window or canopy. Altitudes are "busted" and clearances are violated because a pilot does not follow procedure for a departure, level-off or approach. The ultimate "Oops, I forgot" -- simply forgetting to extend retractable landing gear for landing -- is the most common type of accident in retractable-gear airplanes and is absolutely preventable with proper checklist use.
The most common checklist deviations happen when an outside distraction -- weather, a sick passenger, a radio call, another aircraft in the pattern -- interrupts a pilot's checklist actions. If you get distracted while running a checklist, the safest thing to do is to go back to the beginning of that checklist and verify you've not forgotten anything.
Printed checklists can be cumbersome to use in flight. That's one reason most instructors teach us, incorrectly, to use checklists for the start-up and before takeoff checks, then throw the book in the back or shove the laminated card in a sidewall pocket until we've landed and are ready to shut down.
Checklists do, however, have great value in all phases of flight. But we have to use them correctly. Establish a flight condition or attitude from memory, but then as time permits, pull out the printed checklist and check that you didn't forget something. If I had been in this habit when I flew that Springfield trip, I would have leveled off, completed all actions to the best of my memory, and then right away found my forgotten leaning when I verified my actions on the level-off checklist. If I had been trying for Denver that day instead of Wichita, that may have made the difference between making it to the destination and running out of fuel somewhere over western Kansas.
Instead of using printed checklists, some instructors teach diligent use of mnemonics, or memorized checklists. Used consistently these are excellent checklists in their own right. One of the most famous is CIGARTIP as a before-takeoff check:
- Controls free and correct
- Instruments read correctly
- Gas sufficient for flight and proper tank selected for takeoff
- Angle of flaps
- Run-up magneto, carb heat, and propeller checks as appropriate
- Trim set
- Interior set: Seat belts, doors and windows latched
- Pattern checked for other aircraft.
If you're an instrument pilot, you probably remember the four-, five- or six "T"s (depending on your airplane) for crossing a fix:
- Tune (radios)
- Tires (gear down as appropriate)
- Talk (report to ATC)
Another frequently used for landing is GUMPS :
- Gas set to the proper tank for landing
- Undercarriage (landing gear) down and locked
- Mixture set
- Propeller set
- Switches (fuel pumps, etc.) set as appropriate, and safety check (seatbelts, etc)
Some pilots add a "C" to make the mnemonic C-GUMPS, adding "carb heat"
and "cowl flaps" to the pre-landing check. The "S" is often used as a
reminder for basic "safety" checks as well, such as seatbelts, etc.
Do you have a mnemonic you use? Send me an email -- if we collect enough, they may be subject of a future Leading Edge.
A disciplined pilot may use a combination of printed and mnemonic checklists to fly safely. Commercial operators and especially the airlines have taken this a step further, creating a concept that is also extremely useful in a high-workload, single-pilot aircraft. It's called the cockpit flow.
Airlines developed the cockpit flow as a means of quickly accomplishing proper actions in a complex aircraft at times when, even as a crew, there might not be time to run through a printed checklist. Flows are a memory aid, which of course is the goal of all checklists. Cockpit flows also work well to verify what you did from memory is what you think you did, and that the airplane is properly configured for whatever comes next -- a checklist.
I'm reminded of a retired Air Force pilot who, in the early 1960s, took a C-124 Globemaster (a large, four-engine, propeller transport) to Vietnam as part of the U.S.' early build-up. Once in-country, my friend was detailed to fly a high-priority cargo inland. Since the target airstrip could not possibly accommodate the massive C-124, my friend was ordered to take the trip in a C-47 (DC-3). Trouble was he'd never flown that version of the -3. Wartime emergency and all, he got a quick cockpit check from a crew-chief mechanic: "Move all the shiny switches, and leave the dull-colored switches alone." The implication was that anything that needed to be operated frequently would be shiny metal where the paint was rubbed off. And if it wasn't used a lot, the switch would still be painted black. OK, that's a little beyond our topic, but it does highlight the value of a methodical, visual check of the cockpit to confirm you've configured it the way you intend.
In airline terms a flow is a structured habit pattern that mirrors a printed checklist. In other words it's a memorization aid, and can be used for normal, abnormal and emergency procedures. Since we who fly single-pilot have to do all the work ourselves (at times, ably assisted by an autopilot), the idea of a cockpit flow has great promise. Just "look around the cockpit" and make sure you've not missed anything.
|Flow for engine fire in flight in a Baron. Click here for larger version (190 KB).
Of course, without some structure "looking around" has limited value -- you need to make certain you look at everything that's necessary. Professional training organizations develop pictorial flow references for all conceivable maneuvers and tasks. Below is a translation of the flow concept into a single-pilot Beech Baron for the task of Engine Fire in Flight/Precautionary Shutdown, also shown in the figure at right:
- Fuel selector (failed engine): OFF
- Mixture control (failed engine): IDLE CUTOFF
- Propeller (failed engine): FEATHER
- Auxiliary fuel pump (failed engine): OFF
- Ignition and alternator switches (failed engine): OFF
The flow for a normal-procedure task, like configuring for an instrument approach, might look something like this:
|Flow for configuring a Baron for approach. Click here for larger version (185 KB).
- Power: SET
- Flaps: SET FOR APPROACH (within flap operating speed)
- Attitude: ESTABLISH as appropriate for speed and altitude requirements
- Airspeed: ESTABLISH
- Trim: SET
- Avionics: CONFIRM SET FOR THE APPROACH
Using this technique, you'll need to come up with a specific sequence of events for each flight maneuver and task. Another, far simpler, way is to set things the way you think you should and then -- starting at the point of your choice (for instance, the attitude indicator, or the upper left corner of the instrument panel) -- look across the panel from left to right, then across the circuit breakers and lower subpanels from right to left, and then finally along the seats and floorboards from left to right (for things like fuel selectors, etc.). A quick but methodical visual sweep of the cockpit should help you catch anything that was forgotten or misconfigured. It takes but a few seconds, but if you're disciplined to do it every time you change configuration, altitude or attitude, the cockpit flow is a tremendous boost to the safety of a single-pilot airplane.
Checklists and Flows
Have you ever forgotten where you put your car keys, or to pick up some milk on the way home from work? Did you ever start your engine with chocks still under the nosewheel, or (like me in the A36TC) discover you'd missed a seemingly obvious action like leaning the mixture? Then you need to use some form of checklist. If you do things right, a cockpit flow will become as natural to you as rolling into a bank to turn. You'll literally wear out your printed checklists from use. That's OK, because as you learn and experience more, and as equipment is added or removed from the airplane, you'll want to personalize and revise your checklists for the most efficient ways to fly.
Best use of a checklist comes in concert with flows and mnemonics. You should:
- Configure the cockpit for the desired flight activity from experience and memory, including use of mnemonics;
- Cross-check with a practiced flow pattern to confirm everything is where you think it should be; then
- As time permits, reference a printed checklist to make certain you didn't overlook or forget something.
Fly safe, and have fun!
Thomas Turner's Leading Edge columns are collected here.