Cross-Country Planning (ACS Task D)

Section 91.103 opens with one sentence: "Each pilot in command shall, before beginning a flight, become familiar with all available information concerning that flight" 1. The section then lists what that information must include. For a flight "not in the vicinity of an airport," the list has four items 2:

• weather reports and forecasts
• fuel requirements
• alternatives available if the planned flight cannot be completed
• any known traffic delays that ATC has advised the pilot of.

For any flight, the list adds "runway lengths at airports of intended use" and takeoff and landing distance data. For an airplane with an approved flight manual that carries distance data, the pilot uses that data. For an airplane without one, the pilot uses "other reliable information appropriate to the aircraft," for the expected airport elevation, runway slope, weight, wind, and temperature 2. The Warrior's manual carries takeoff and landing charts, so the pilot uses those charts.

NOTAMs are part of all available information

A NOTAM carries time-critical information that the chart does not show yet, such as:

• a closed runway
• an unlit tower
• a restricted block of airspace.

The AIM says the NOTAM system "provides pilots with time critical aeronautical information that is temporary, or information to be published on aeronautical charts at a later date" 3. A temporary flight restriction is a NOTAM. The AIM: TFRs "restrict entrance to a certain airspace at a certain time" 4. The NOTAM check, with TFRs, is part of each cross-country preflight. The rule says all available information, and a NOTAM is available.

The briefing is a rehearsal

Advisory Circular 91-92 describes the preflight action as one rehearsal. Each pilot "should review all appropriate sources (including but not limited to Chart Supplements, the AIM, and NOTAMs)" for the traffic patterns, routing, NOTAMs, weather, alternates, "fuel and timing," and takeoff and landing data. The circular's summary: "Preflight actions are a rehearsal of the whole flight with contingencies added" 5. The same circular says "a self-briefing may be compliant with current Federal aviation regulations," with Flight Service available when the pilot needs help 5.

The sectional chart is the planning chart for a private pilot cross-country. The Pilot's Handbook: "Sectional charts are the most common charts used by pilots today. The charts have a scale of 1:500,000 (1 inch = 6.86 nautical miles (NM) or approximately 8 statute miles (SM))" 6. Each sectional covers a named region. The Chart Users' Guide: "Sectionals are named after a major city within its area of coverage" 7. For a route near the edge of a chart, the pilot needs the adjoining chart too 8.

The 56-day cycle

A sectional expires. The Chart Users' Guide: "These charts are updated every 56 days" 7. A pilot who plans on an expired chart can miss:

• a new tower
• a changed frequency
• a changed airspace boundary.

The Pilot's Handbook still says sectionals "are revised semiannually" 6. The Chart Users' Guide is the current source, and its figure is 56 days. The chart carries its effective dates.

The Chart Supplement

The chart shows an airport as a symbol. The Chart Supplement shows the airport as a page. The Pilot's Handbook lists what the pilot reads there for each airport of intended landing: "location, elevation, runway and lighting facilities, available services, availability of aeronautical advisory station frequency (UNICOM), types of fuel available (use to decide on refueling stops), FSS located on the airport, control tower and ground control frequencies, traffic information, remarks, and other pertinent information" 9. When the chart and the Chart Supplement disagree, the Chart Supplement "should be used in preference to the information on the back of the chart" 9.

The pilot picks frequencies on the ground

Frequency selection is part of planning. The nav log for each leg carries:

• the VOR frequencies and radials that will confirm position
• the CTAF or tower frequency at each airport, with ground and ATIS or AWOS
• the approach control or center frequency for flight following.

The sectional's legend carries "air traffic control (ATC) frequencies and information on airspace," and the Chart Supplement carries the tower and ground frequencies 6. The pilot dials a frequency found on the ground with one hand. A search for a frequency in flight takes both hands and the pilot's attention.

Route selection starts with the airspace the course line crosses. The Pilot's Handbook: "The course and areas on either side of the planned route should be checked to determine if there is any type of airspace with which the pilot should be concerned or which has special operational requirements" 10. The handbook's worked example crosses a Class C shelf with a floor of 2,500 feet MSL and a Class D around a towered field 10. Class B requires a clearance. Class C and Class D require two-way communication before entry 11 12 13.

The pilot identifies special use airspace on the chart and checks its hours and status 14. A route that avoids a Class B by ten miles can take less time than a route through it. The pilot on the direct route waits for a clearance.

Emergency options along the route

The shortest line is not always the best route. The Pilot's Handbook, in the PAVE checklist: "Choose the flight route wisely. An engine failure gives the nearby airports supreme importance" 15. The pilot checks the route for three things:

• the terrain under it, and whether a forced landing there is survivable
• the airports along it, and the distance between them
• the glide range from the planned altitude, and whether an airport is inside it for most of the leg.

The handbook's route study names "particularly rugged terrain so it can be avoided" and towers that "may extend to altitudes over 1,500 feet above the surrounding terrain" 16. A dogleg that follows a valley with three airports adds five minutes. A straight line over a ridge with no airport saves those five minutes and has no landing site inside the glide.

An electronic flight bag can replace the paper chart for VFR flight. Advisory Circular 91-78A sets four criteria. The EFB does not replace required equipment. It displays "only information which is functionally equivalent to the paper reference material," and it does not interfere with airplane systems. The fourth criterion is that "the interactive or precomposed information being used for navigation or performance planning is current, up to date, and valid, as verified by the pilot" 17.

The last criterion is the pilot's job before each flight. The pilot checks the chart edition and the database date on the ground.

The EFB can fail, so the plan includes its failure

A tablet has a battery and a temperature limit. Its screen is hard to read in direct sun. The circular's assessment covers "display and lighting issues, system shutdown, and system failures," and its training covers "preflight checks of the system" 18. The plan for a tablet on a cross-country has three parts:

• charge state before flight, and a power source in the airplane
• a backup, which is a second device or a paper chart for the route
• shade and airflow for the device, because a tablet in direct sun on the glareshield shuts itself down when it overheats.

A pilot with the nav log on paper and the frequencies written down finishes the flight when the tablet fails. A pilot with everything on the tablet navigates by memory.

The EFB is an aggregator

The weather and NOTAMs on a tablet come from products with their own limits. Advisory Circular 91-92 says of in-cockpit radar that the NEXRAD mosaic "can be 15 to 20 minutes old by the time they are assembled and displayed in a cockpit" 19. The same circular says the FIS-B feed "may not include all of the weather products or NOTAMs that a preflight briefing includes" 19. When the app's summary and the raw product disagree, the raw product is the authority. The app summarized it. The product is what the forecaster wrote.

The cruising altitude must clear the terrain and the obstacles along the whole route, not only at the ends. The Pilot's Handbook: "Study the terrain and obstructions along the route. This is necessary to determine the highest and lowest elevations, as well as the highest obstruction to be encountered so an appropriate altitude that conforms to 14 CFR part 91 regulations can be selected" 16. The sectional prints a summary of that study in each quadrant, the Maximum Elevation Figure.

The MEF

The MEF is the large blue number in each quadrant of the sectional. The Chart Users' Guide: "The Maximum Elevation Figure (MEF) represents the highest elevation within a quadrant, including terrain and other vertical obstacles (towers, trees, etc.). A quadrant on Sectionals is the area bounded by ticked lines dividing each 30 minutes of latitude and each 30 minutes of longitude. MEF figures are rounded up to the nearest 100' value and the last two digits of the number are not shown" 20. An MEF of 4⁷ means the highest feature in that quadrant is at or below 4,700 feet MSL.

The MEF is not a cruising altitude. The guide's calculation adds only the source's possible vertical error and, over natural terrain, "a 200' allowance for uncharted natural or manmade obstacles" before rounding up, and the guide says its figures "are not verified by field surveys" 20. Those allowances cover the chart's own error, not the airplane's clearance. The pilot adds a clearance margin above it. North Aero's planning margin is 1,000 feet above the highest MEF on the leg by day, and more at night. An MEF of 4⁷ and a day margin of 1,000 feet gives a floor of 5,700 feet. The pilot rounds that floor up to the next legal cruising altitude for the direction of flight.

A higher altitude gives more glide

A higher cruising altitude gives glide distance. The Warrior's glide chart gives about 2 statute miles for each 1,000 feet above the terrain, at 85 mph with the propeller windmilling and no wind 21. Twice the altitude above the terrain is twice the distance to a field after an engine failure. The larger circle covers four times the area, and more airports. The Pilot's Handbook's question for the route is which airports the airplane can reach after an engine failure 15. Altitude determines the answer to that question.

The hemispheric rule

Section 91.159 assigns cruising altitudes by direction. In level VFR cruise "more than 3,000 feet above the surface" and below 18,000 feet MSL, "on a magnetic course of zero degrees through 179 degrees, any odd thousand foot MSL altitude + 500 feet (such as 3,500, 5,500, or 7,500)" and "on a magnetic course of 180 degrees through 359 degrees, any even thousand foot MSL altitude + 500 feet (such as 4,500, 6,500, or 8,500)" 22. The rule does not apply when ATC authorizes another altitude, during a turn, or in a short hold 22.

The rule uses magnetic course, not heading. A course of 175 degrees with a 20-degree wind correction gives a heading of 195 degrees. The legal altitudes are still odd plus 500, because the course is 175. The wind correction the pilot flies never changes which altitudes are legal. The pilot reads the course from the nav log, not the heading from the directional gyro.

Winds aloft

The forecast winds aloft change groundspeed with altitude, and groundspeed changes fuel. A 20-knot headwind at 7,500 feet and a 10-knot headwind at 5,500 feet is a choice. The higher altitude gives more glide and costs 10 knots and the fuel to climb 2,000 more feet. The lower altitude saves the climb and the 10 knots and has less glide.

Advisory Circular 91-92 has the pilot "interpolate wind directions and speeds between levels and stations, noting any large shifts in speeds or direction" 23. The pilot weighs the wind advantage against terrain clearance and the cost of the climb. The nav log shows the result as a groundspeed for each leg.

Time en route for a leg is the leg distance divided by the groundspeed. The Pilot's Handbook: "Estimated time en route (ETE)—total distance divided by GS" 24. Its example: "If the distance measures 220 NM, divide by the GS of 88 knots, which gives 2.5 hours, or 2:30, as the time required" 24. A 65-mile leg at 100 knots takes 39 minutes. The same leg at 80 knots takes 49 minutes. Twenty knots of wind is ten minutes on a 65-mile leg.

Groundspeed is true airspeed corrected for wind

The wind does not change the airspeed. It changes the progress over the ground. The Pilot's Handbook: an airplane "flying eastward at an airspeed of 120 knots in still air has a groundspeed (GS) exactly the same—120 knots. If the mass of air is moving eastward at 20 knots, the airspeed of the aircraft is not affected, but the progress of the aircraft over the ground is 120 plus 20 or a GS of 140 knots" 25. With the air moving westward, the groundspeed "becomes 120 minus 20 or 100 knots" 25.

A headwind component lowers the groundspeed. A tailwind component raises it. A crosswind at an angle gives a component of each, and the flight computer resolves it.

The pilot budgets the climb separately

The climb is slower over the ground, burns more fuel per mile, and covers distance while it does both. The Pilot's Handbook: "you must plan for cruise flight as well as startup and taxi, and higher fuel burn during climb. Remember that ground speed during climb is less than during cruise flight at the same airspeed" 26.

The Warrior's climb chart gives the rate of climb at full throttle, at gross weight, at 87 miles per hour, against density altitude 27. The manual recommends 100 miles per hour for the en route climb 28. The pilot reads the rate at the field's density altitude and at the cruise altitude, averages them, and gets the minutes to top of climb. The minutes give the distance at climb groundspeed and the fuel at climb burn. Those three numbers, time, distance, and fuel, are the first line of the nav log, before cruise begins.

The pilot plans the descent backward

The pilot plans the descent from the destination back toward the airplane. The pilot chooses a descent rate and a groundspeed, then finds the distance the descent needs.

A cruise altitude of 5,500 feet and a pattern altitude of 1,000 feet is 4,500 feet to lose. At 500 feet per minute, 4,500 feet is 9 minutes. At 110 knots groundspeed in the descent, 9 minutes is about 16 miles. The descent begins 16 miles out, plus a mile or two to slow down before the pattern. The arithmetic is the same distance, speed, and time relation as the leg 24. A pilot who starts the descent late arrives high and fast over a pattern full of airplanes.

Times are in UTC

Flight plan times and estimates are in Coordinated Universal Time. The AIM: "FAA uses Coordinated Universal Time (UTC) for all operations. The word 'local' or the time zone equivalent must be used to denote local when local time is given during radio and telephone communications. The term 'Zulu' may be used to denote UTC" 29.

The pilot converts local time to UTC with the zone offset from the AIM's table. Pacific standard time adds 8 hours. Pacific daylight time adds 7. A departure at 6 in the evening Pacific daylight time is 0100 UTC the next day. The date changes with the hour, and the nav log carries the UTC date.

Each weather product is already in UTC. The Aviation Weather Handbook on the METAR: "The date and time group always ends with a Z, indicating Zulu time (or Coordinated Universal Time (UTC))" 30. The TAF and the briefing use the same convention. The pilot converts once, at the start, and the nav log stays in one time system. A log with local departure times and UTC forecast times mixes two time systems, and a mixed log produces errors.

Leg fuel is leg time multiplied by the fuel burn for the power setting. The Pilot's Handbook: "The amount of fuel needed for a given flight can be calculated by multiplying the estimated flight time by the rate of consumption" 26. The Warrior's range chart gives the rates, leaned, at gross weight: "75% POWER 9.2 GPH. 65% POWER 8.0 GPH. 55% POWER 6.7 GPH" 31. A 39-minute leg at 65 percent power is 0.65 hours times 8.0 gallons, which is 5.2 gallons.

Total fuel required

The total is a sum, and each term is on the nav log:

• taxi and runup
• the climb, at climb burn for the climb minutes
• each cruise leg, at cruise burn for the leg minutes
• the descent
• the legal reserve, and the personal reserve above it.

The Pilot's Handbook adds the reserve to that sum: "there should be sufficient fuel for reserve" and "Additional fuel for adequate reserve should also be added as a safety measure" 26. The tanks' usable fuel must cover the whole sum. When the sum is larger than the usable fuel, the pilot adds a fuel stop. The pilot chooses the stop on the ground, from the Chart Supplement's fuel column.

The legal minimum

Section 91.151 sets the floor. The rule: "No person may begin a flight in an airplane under VFR conditions unless (considering wind and forecast weather conditions) there is enough fuel to fly to the first point of intended landing and, assuming normal cruising speed" and then "During the day, to fly after that for at least 30 minutes; or At night, to fly after that for at least 45 minutes" 32. The rule measures the reserve at normal cruising speed. In the Warrior at 65 percent power, 30 minutes is 4 gallons and 45 minutes is 6 gallons. The rule counts the wind and the forecast. A plan that works in still air and fails in the forecast headwind is not legal.

The floor is not the plan

The 30 minutes is a legal floor, not a planning number. The Risk Management Handbook has pilots set personal minimums "more restrictive than the regulatory requirements" and says established minimums "enable the pilot to make a no-go or divert decision rather than departing with a sense of unease" 33. North Aero plans with a one-hour reserve by day and by night, fixed before the flight. The pilot lands before the reserve hour begins. A pilot who lands with the hour intact planned the flight correctly. A pilot who lands with 30 minutes used the legal reserve as trip fuel, and had no margin left for a headwind stronger than forecast.

Usable fuel

The planning number is usable fuel, not total fuel. The Warrior's manual: "Fuel is stored in two twenty-five gallon (24 gallons usable) fuel tanks, giving the airplane a total capacity of fifty U.S. gallons (48 gallons usable)" 34. Two gallons sit in the tanks and cannot reliably reach the engine in flight attitudes. A plan built on 50 gallons has two gallons in it that the engine cannot use, which is 15 minutes at cruise.

The flight of N7682U

On January 15, 2024, at 2:48 in the afternoon, a Cessna 150M lost all engine power in the pattern at Venango Regional Airport, Franklin, Pennsylvania. The pilot, a 27-year-old private pilot with about 110 hours, tried to land on a taxiway. She struck a berm in the flare and suffered serious injuries. She was alone in the airplane with a 50-pound pet pig. The flight was a solo VFR cross-country from Beverly, Massachusetts, toward Detroit, in several legs 35.

The Cessna 150 carries 26 gallons, of which 22.5 are usable, and 3.5 are not. About 90 minutes into the first leg the pilot "diverted to Albany International Airport (ALB), Albany, New York, because the airplane's fuel quantity indicated lower than expected." She added 13 gallons, "for a total fuel load of 22.5 gallons usable fuel," and took off for Youngstown, Ohio, "about 320 miles to the west" 35. That first diversion was a correct decision.

She flew the second leg at 4,000 and 5,000 feet into a wind from 247 degrees at 16 knots, on a track of 255 degrees. The groundspeed averaged 72 knots. The NTSB's fuel calculation from the handbook: "the airplane would have had an endurance of about 3.75 hours with full fuel tanks; however, this endurance was dependent on fuel mixture leaning settings. The data showed that the airplane was airborne about 4 hours" 35.

"About 3 1/2 hours and 255 nm into the flight, she diverted to FKL, about 40 nm closer than YNG." The reason she gave the NTSB was "to get fuel because the fuel was less expensive than at YNG" 35. She began the descent 30 miles out, entered the pattern for runway 21, overshot final, and circled for another try. During the circle the engine stopped responding to the throttle, and then it stopped.

Investigators drained "about 3 1/2 gallons" from the intact tanks, which is the unusable quantity, and found the gascolator empty. The engine had no defect. The probable cause: "The pilots' inadequate preflight fuel planning and in-flight fuel management, which resulted in a total loss of engine power due to fuel exhaustion" 35.

Where the pilot could have prevented the accident

The fuel ran out because the plan did not include enough fuel. Each decision below carries the PAVE category that applied to it.

A VFR flight plan exists for search and rescue. It tells Flight Service where the airplane was going and when it was due, so a search begins where the airplane should be. The AIM: "Activating the flight plan will ensure that you receive VFR Search and Rescue services" 36. The flight plan is not a clearance. It is a record held by the people who will search.

Not required, and still filed

The AIM: "Within the continental U.S., a VFR flight plan is not normally required" 36. A flight into an Air Defense Identification Zone or across the border requires one. For other flights, the AIM says filing "is strongly recommended" 36. Filing takes five minutes on the telephone or in the app. North Aero files one for each solo cross-country.

What the plan carries

The pilot files the plan on FAA Form 7233-4, the international flight plan form 36. Its items are:

• aircraft identification and type
• departure point and proposed departure time
• route and cruising altitude
• destination and estimated time en route
• fuel on board as endurance, in hours and minutes
• persons on board
• the pilot's name and contact information, and the airplane's color.

The last three are Item 19. The AIM: Item 19 "will be retained by the facility/organization that transmits the flight plan to Air Traffic Control (ATC), for Search and Rescue purposes, but it will not be transmitted to ATC as part of the flight plan," and the minimum entries are "Endurance, Persons on Board, Pilot Name and Contact Information, and Color of Aircraft" 37. The color of the airplane is on the form because searchers look for a color.

Filing is not activating

A filed plan is held until the pilot activates it. The pilot opens it after departure. The AIM: "Pilots are encouraged to activate their VFR flight plans with Flight Service by the most expeditious means possible. This may be via radio or other electronic means. VFR flight plan proposals are normally retained for two hours following the proposed time of departure" 36. The means are:

• the radio to Flight Service
• the telephone
• the app's link to Flight Service.

The tower does not activate it: "U.S. air traffic control towers do not routinely activate VFR flight plans" 36. A plan can also open at an assumed departure time, and an unrevised departure time then starts the search at the wrong hour 38.

Closing is the pilot's job

The AIM: "A pilot is responsible for ensuring that his/her VFR or DVFR flight plan is canceled. You should close your flight plan with the nearest FSS, or if one is not available, you may request any ATC facility to relay your cancellation to the FSS. Control towers do not automatically close VFR or DVFR flight plans since they do not know if a particular VFR aircraft is on a flight plan" 39. A tower that clears the airplane to land has not closed the flight plan. The pilot closes it on the ground, by radio, telephone, or app.

Thirty minutes

The AIM: "If you fail to report or cancel your flight plan within 1/2 hour after your ETA, search and rescue procedures are started" 39. The search starts with telephone calls to the destination and the pilot's contact number, and then expands. A pilot who forgets to close a plan must explain the mistake to the searchers. No one searches for a pilot who never filed a plan and crashes in the hills, until someone notices the empty hangar.

A fighter or a helicopter can intercept an airplane in the wrong airspace. International agreement fixes the signals. The AIM's table, Series 1: the interceptor rocks its wings "from a position slightly above and ahead of, and normally to the left of, the intercepted aircraft and, after acknowledgement, a slow level turn, normally to the left, on to the desired heading." The meaning: "You have been intercepted. Follow me." The intercepted airplane answers with "Rocking wings and following" 40. At night the interceptor adds flashing navigation lights.

The intercepted pilot's actions

The AIM's summary of the intercepted pilot's actions, each "without delay":

• "Adhere to instructions relayed through the use of visual devices, visual signals, and radio communications from the intercepting aircraft."
• "Attempt to establish radio communications with the intercepting aircraft or with the appropriate air traffic control facility by making a general call on guard frequencies (121.5 or 243.0 MHz), giving the identity, position, and nature of the flight."
• "If transponder equipped, select Mode 3/A Code 7700 unless otherwise instructed by air traffic control" 41.

The pilot holds a steady course until the interceptor signals a change, and notifies ATC as soon as the pilot has contact. The AIM also asks each airplane to "maintain a listening watch on VHF/UHF guard frequencies" and warns that "Noncompliance may result in the use of force" 41. In an airplane with two radios, the second is set to 121.5 in cruise.

The usual cause is an unchecked TFR

In most cases the reason for an interception of a private pilot is a temporary flight restriction the pilot did not know about. TFRs cover events such as:

• a stadium game
• a presidential visit
• a fire
• a launch.

The mitigation is the preflight NOTAM check, because a TFR is a NOTAM and the rule requires all available information 4 1. Advisory Circular 91-92 lists "NOTAMs (e.g., airport/runway closures, air traffic delays, and TFRs)" in the adverse conditions of each briefing 23. A TFR found on the ground is a line on the chart. A TFR found in the air is an interception.

The PAVE checklist from Module 1-1 applies to each flight. A cross-country applies each letter over more hours and more miles 42. The Pilot's Handbook asks the pilot, for the P, "Am I ready for this trip?" in terms of experience, recency, currency, physical, and emotional condition 43. On a cross-country the trip is four hours of flying, not one. The duration adds:

• fatigue, which begins in the third hour and not the first
• food and water, carried, because the headache starts in the third hour
• currency for the length and the conditions of the trip, the night landings for a night arrival, the recent cross-country time for a long one.

The Aircraft letter on this route

The A covers whether this airplane is equipped and legal for this route. The handbook's questions: "Is this aircraft equipped for the flight? Instruments? Lights? Navigation and communication equipment adequate?" and "Does this aircraft have sufficient fuel capacity, with reserves, for trip legs planned?" 44. For a cross-country the list is:

• avionics for the route, a working VOR receiver and a transponder for the airspace
• lighting, when the arrival time is after sunset
• inspections current through the return, including the days away
• performance adequate for each runway, from the manual's charts.

The enVironment letter, leg by leg

The pilot checks the V along the whole route. The weather at the endpoints is not the weather at the ridge between them. The handbook's environment questions include the NOTAMs, "nearby towers," the route chosen for its airports, "the airspace and any temporary flight restriction (TFRs) along the route of flight," and shorter fields at the destination and alternate 15. For each leg the nav log has a column for each of four things: weather, terrain, airspace, obstacles. A leg with a blank in any column is not planned.

The reason you must arrive is a risk

The E is the reason the flight must arrive, and that reason is a hazard. The Pilot's Handbook: "Management of external pressure is the single most important key to risk management because it is the one risk factor category that can cause a pilot to ignore all the other risk factors" 45. The pilot arranges the mitigation before takeoff. The handbook's list includes:

• "Allow time on a trip for an extra fuel stop or to make an unexpected landing because of weather."
• "Have alternate plans for a late arrival or make backup airline reservations for must-be-there trips."
• "Advise those who are waiting at the destination that the arrival may be delayed" 45.

An extra day, a backup ride, and a planned alternate turn "must arrive" into "would like to arrive." A pilot with those three arrangements has no hard decision to make in the air.

VFR flight following is a service, not a guarantee. The AIM on radar traffic information: "Many factors, such as limitations of the radar, volume of traffic, controller workload and communications frequency congestion, could prevent the controller from providing this service. Controllers possess complete discretion for determining whether they are able to provide or continue to provide this service" 46. ATC can refuse it and can end it. Radar and radio coverage have floors, and a Warrior at 3,500 feet in a valley can be below both. The plan does not depend on it.

No service relieves the pilot

The AIM: the service "is not intended to relieve the pilot of the responsibility for continual vigilance to see and avoid other aircraft" 46. Section 91.113(b) puts the duty on the pilot: "vigilance shall be maintained by each person operating an aircraft so as to see and avoid other aircraft" 47. The same holds for terrain and airspace. A controller who says "radar contact" has not taken over the terrain clearance, the Class D ahead, or the traffic scan. Those duties stay with the pilot for the whole flight.

The fuel decision point

A fuel decision point is a named point on the route, chosen before flight, with a fuel number attached. At that point the pilot compares the fuel on board with the plan. Below the planned number, the pilot lands and refuels at the airport chosen for that case. The pilot makes the decision on the ground and only carries it out at the point.

The Pilot's Handbook: "You should always plan to be on the surface before any of the following occur: Your flight time exceeds the amount of flight time you calculated for the consumption of your preflight fuel amount; Your fuel gauge indicates low fuel level" 26. Advisory Circular 91-92 lists "Fuel requirements" and "Alternate airports" on the preflight checklist beside PAVE and personal minimums 48. The pilot of N7682U had no decision point. She chose the airport by price.

Night planning raises the altitude floor. The terrain and obstacles the day pilot avoids by eye are invisible at night, so the clearance margin above the MEF grows. The Airplane Flying Handbook: "Although careful planning of any flight is essential, night flying demands more attention to the details of preflight preparation and planning" 49. North Aero's night margin is 2,000 feet above the highest MEF on the leg, against 1,000 by day. The handbook's night emergency procedure begins "establish the best glide configuration and airspeed. Turn the airplane towards an airport" 50. The extra altitude is the glide to that airport.

Night checkpoints are lighted

A checkpoint the pilot cannot see is not a checkpoint. The Airplane Flying Handbook: "Rotating beacons at airports, lighted obstructions, lights of cities or towns, and lights from major highway traffic all provide excellent visual checkpoints" 51. The day checkpoints that disappear at night are:

• section lines and fence lines
• dry creeks and small rivers
• unlit towers
• small towns with no lights on the highway.

The handbook adds that "night cross-country flights do not present particular problems if pre-planning is adequate," and that the pilot "continuously monitors position, time estimates, fuel consumed" 51. The pilot checks the lighting at the destination before the flight, on the chart, in the Chart Supplement, and in the NOTAMs 52.

Night routes follow the lights

A night route uses lighted corridors and stays within glide of lighted airports, at some cost in distance. A highway with a town at fifteen-mile intervals is a route with a checkpoint at fifteen-mile intervals and a lit road under the airplane. A straight line across dark hills is a shorter route with no checkpoints and no landing options. The handbook's engine-failure procedure at night turns "towards an airport or away from congested areas" and, when the terrain is unknown, toward "an unlighted portion of the area" 50. The route that keeps a lighted airport inside the glide circle makes the first choice available.