PART 61KSNSGROUND SCHOOL
North Aero NORTH AERO

Phase 1 · Module 1-15

Engine Failure Decisions (When the Fan Stops)

After an engine failure, the pilot sets best glide speed before any other action. The Warrior's manual gives the number: "If loss of power occurs at altitude, trim the aircraft for best gliding angle 85 MPH, and look for a suitable field" . The Airplane Flying Handbook gives the technique: "If the simulated power failure occurs while above best glide speed, the pilot allows the airplane to slow (or may even bleed off speed by climbing) until reaching best glide speed. When reaching that speed, the nose can be lowered and the airplane trimmed to maintain that speed. If the failure occurs at or below best glide speed, the nose should be lowered immediately to maintain or accelerate to best glide speed" . Altitude gives the pilot time and distance. The pilot does not use altitude to fly faster than the number, and does not fly slower than it. The handbook says: "A constant gliding speed is usually maintained because variations of gliding speed nullify all attempts at accuracy in judgment of gliding distance and the landing spot" .

The Warrior's two numbers

The Warrior glides at 85 MPH. When the pilot is certain the airplane can reach the field, the manual gives a second number: "When the field can easily be reached, slow up to 76 MPH for the shortest landing" . The pilot flies 85 MPH from the moment the engine stops until the field is certain. The pilot flies 76 MPH on final, when the only remaining question is where on the field the airplane touches down.

Best glide and minimum sink

Best glide speed gives the most distance for each foot of altitude. Minimum sink speed gives the most time in the air, and it is slower. The pilot chooses the speed by what the pilot needs. A pilot gliding toward a field needs distance and flies best glide. A pilot with no field in reach, who waits for a restart over water or wants to be found, needs time and flies slower. The Warrior's manual publishes one number, 85 MPH, and the pilot flies it unless time in the air is the only need.

Wind changes the glide

A headwind steepens the path over the ground. A tailwind extends it. The handbook's approach planning begins with "wind direction and velocity," and the handbook warns against the stretched glide: "A pilot who overestimates the gliding range may be tempted to stretch the glide across obstacles in the approach path" . Between two equal fields, the pilot chooses the downwind field, because the glide reaches it. The pilot lands into the wind on that field, because the landing roll is shorter. The handbook lists the places a pilot reads the wind: "the windsock at the airport, smoke from factories or houses, dust, brush fires, wind farms, or patterns displayed on nearby bodies of water" .

The number of fields within gliding range grows with altitude. The handbook says: "A pilot's choice of emergency landing sites is governed by: the route selected during preflight planning, the height above the ground when the emergency occurs, excess airspeed." The handbook adds: "The only time the pilot has a very limited choice is during the low and slow portion of the takeoff" . A Warrior gliding at 85 MPH from 6,500 feet has minutes of gliding time and a wide area of ground to choose from. The same airplane at pattern altitude can reach the airport and the fields next to it. On climb-out at 300 feet the airplane can reach only the ground ahead of the nose.

A low pass or low cruise leaves the pilot only the ground ahead. Section 91.119(a) sets the minimum altitude everywhere: "an altitude allowing, if a power unit fails, an emergency landing without undue hazard to persons or property on the surface" . The rule assumes the engine will quit.

The Warrior's manual gives the restart in seven items. "Maintain an airspeed of at least 85 MPH, and if altitude permits, proceed as follows: 1. Fuel Selector - Switch to another tank containing fuel. 2. Electric Fuel Pump - On 3. Mixture - Rich 4. Carburetor Heat - On 5. Engine Gauges - Check for indication of the cause of power loss. 6. Primer - Check locked 7. If no fuel pressure is indicated, check tank selector position to be sure it is on a tank containing fuel" . The airspeed comes before the first item. The pilot does the seven items from memory, in order, and reads the checklist afterward if there is time.

The other tank

The most common restart is the other tank. The manual's operating instructions say so: "The most common cause of engine power loss is mismanagement of fuel. Therefore, the first step to take after engine power loss is to move the fuel selector to the tank not being used. This will often restore power even if there is no apparent reason for the engine to stop on the tank being used" . Item seven repeats the check. No fuel pressure after the first six items means the pilot looks at the selector again. A selector between detents or on an empty tank gives the same fuel pressure reading as no pump.

The manual adds a note for a tank that has run dry: "If engine failure was caused by fuel exhaustion, power will not be restored after tanks are switched until empty fuel lines are filled, which may require up to ten seconds" . A pilot who switches tanks and gives up after three seconds stops before the fuel lines are full.

If time permits

With altitude left after the seven items, the manual continues: "1. Ignition Switch - 'L' then 'R' then back to 'BOTH.' 2. Throttle and Mixture - Different settings. 3. Try another fuel tank. (Water in the fuel could take some time to be used up, and allowing the engine to windmill may restore power. If power loss is due to water, fuel pressure indications will be normal.)" . The handbook's list of critical items is the same list: "the position of the fuel tank selector, the quantity of fuel in the tank selected, the fuel pressure gauge to see if the electric fuel pump is needed, the position of the mixture control, the position of the magneto switch, and the use of carburetor heat." The handbook adds the history: "Many actual emergency landings have been made and later found to be the result of the fuel selector valve being positioned to an empty tank while the other tank had plenty of fuel" .

Engines stop for reasons a pilot can name. Fuel starvation is fuel aboard that does not reach the engine. Three causes are:

The Warrior's manual calls fuel mismanagement "the most common cause of engine power loss" . Starvation is nearly always the pilot's error, and the pilot can nearly always prevent it. The pilot keeps the selector on a tank with fuel, moves it by the clock, and confirms the flow on the fuel pressure gauge.

Fuel exhaustion

Fuel exhaustion is no fuel left aboard. It is a planning failure. The failure begins on the ground at the preflight quantity check, and continues in the air, where the pilot reads the gauge against the watch. The handbook lists fuel exhaustion among the situations a pilot allows to become a forced landing: "the pilot facing imminent fuel exhaustion who does not give any thought to the feasibility of a precautionary landing, accepts an extremely hazardous alternative" . A precautionary landing with an hour of fuel is a landing. A forced landing with no fuel is an emergency.

Carburetor ice

The Warrior's engine has a float carburetor, and a float carburetor can form ice. The Pilot's Handbook says: "Carburetor ice occurs due to the effect of fuel vaporization and the decrease in air pressure in the venturi, which causes a sharp temperature drop in the carburetor. If water vapor in the air condenses when the carburetor temperature is at or below freezing, ice may form on internal surfaces of the carburetor, including the throttle valve" .

The handbook's chart puts the high-risk band between about 20°F and 70°F with high humidity. The ice forms most readily at low power. In a fixed-pitch airplane, carburetor ice shows as a slow decay in rpm and roughness. The engine does not stop at once. It loses a hundred rpm, then another hundred. A pilot who does not watch the tachometer adds throttle, and the added throttle conceals the loss.

Carburetor heat stays on

The pilot applies full carburetor heat and leaves it on. The handbook says: "If detected, full carburetor heat should be applied immediately, and it should be left in the ON position until the pilot is certain that all the ice has been removed. If ice is present, applying partial heat or leaving heat on for an insufficient time might aggravate the situation." The roughness is the ice leaving the engine. Applying heat "will further reduce power and may cause engine roughness as melted ice goes through the engine. These symptoms may last from 30 seconds to several minutes, depending on the severity of the icing. During this period, the pilot must resist the temptation to decrease the carburetor heat usage" . The tachometer shows the sequence: "there is a decrease in rpm, followed by a gradual increase in rpm as the ice melts" . The engine runs rough for a moment as the melted ice passes through it. A pilot who turns the heat off at that moment stops the cure at the worst point.

Water and sediment in the fuel show at low power or at the first tank switch. The handbook says: "Accidents attributed to powerplant failure from fuel contamination have often been traced to: inadequate preflight inspection by the pilot, servicing aircraft with improperly filtered fuel from small tanks or drums, storing aircraft with partially filled fuel tanks, lack of proper maintenance." The sump check finds contamination: "Fuel should be drained from the fuel strainer quick drain and from each fuel tank sump into a transparent container and then checked for dirt and water," and "if water or other contaminants are found in the first sample, drain further samples until no trace appears" . A full-power runup check finds what the sump missed. Water in a new tank reaches the engine in the first minute on that tank. For that reason the pilot switches tanks over an airport when the route allows it.

Magnetos

Magneto or ignition failure shows as roughness that changes with the magneto switch. The pilot troubleshoots with the runup check flown in the air. The manual lists that check among the steps if time permits: "Ignition Switch - 'L' then 'R' then back to 'BOTH'" . The manual's operating instructions say the same: "Check ignition switch. Turn to best operating magneto - LEFT, RIGHT, or BOTH" . The result can be one magneto and a precautionary landing. An engine on one magneto runs, but it is not an engine for a flight home.

Rough at altitude: the order

At 6,500 feet the pilot has time, and the order of actions is:

The manual's power-off landing procedure has the same order: trim for 85, "look for a suitable field," then "if measures taken to restore power are not effective, and if time permits, check your charts for airports in the immediate vicinity" . A pilot who runs the checklist first, with no field chosen and the airspeed drifting, uses the altitude on the wrong task.

Rough at 1,000 feet: land

The same symptom at 1,000 feet in the pattern has a different answer. The field is the runway under the wing, and the pilot flies the airplane to it. The manual's fuel management list warns against one item at low altitude: "Fuel tank selection at low altitude is not recommended since adequate recovery time is essential in the event of an error in fuel selection" . At 6,500 feet a selector error costs a few hundred feet, and the pilot finds it. At 1,000 feet the pilot does not have the recovery time that error needs.

The pilot turns on carburetor heat and the electric fuel pump with the free hand. The tank stays where it is. The airplane lands.

The flight of N545PZ

On October 1, 2023, at 4:08 in the afternoon, a Cessna 177RG Cardinal took off from runway 32 at Lake Placid, New York. The airplane lost part of its power and flew about a mile at 300 to 400 feet. It then turned hard back toward the airport and stalled into an embankment 440 feet short of the runway. The pilot was a 70-year-old commercial pilot with about 9,000 hours and 10 in the type. The pilot-rated passenger was a 63-year-old flight instructor. Both died .

The flight was a photo flight. A Beech Bonanza with a photographer aboard took off first. The Cardinal followed about 700 feet behind it to join up. On the taxi out, the Cardinal's engine stopped on its own and restarted five seconds later. On the takeoff roll a witness heard the engine surge. In the initial climb the engine "sounded to the witness as if it were not running at full power."

The Cardinal used about 100 feet more runway than the Bonanza. Just after liftoff, a glider pilot across the field saw "white smoke" from its exhaust for a moment. The airplane turned gently left toward the Bonanza at 300 to 400 feet, "barely going up," and flew that way for about a mile .

The airplane then turned hard right toward the airport. The Bonanza's pilot heard the instructor on the CTAF say "something similar to, 'we have a problem and we're returning to the airport.'" The glider pilot watched the turn. The Cardinal was "always turning right" and never flew a square base leg. The glider pilot reported that "when the airplane's heading was 80° to 90° off the runway heading and it was still 300 to 400 ft agl, the 'nose dropped down' and the airplane continued to turn right heading for the runway threshold" .

The photographs from the Bonanza showed the flaps partly extended. Just before impact, they showed the landing gear possibly in transit and a nose-up pitch input. The airplane hit the embankment right wing down and nose low, 440 feet from the threshold and 250 feet left of the centerline.

The engine ran to the end. A sound analysis of a video put it at about 2,125 rpm in the last seconds. The examination found no failure that would have stopped the engine. The density altitude was about 2,758 feet. The NTSB calculated that this density altitude would have lengthened the takeoff by about 37 percent and cut the climb rate by about 28 percent.

The pilot did no weight and balance calculation. The probable cause: "A partial loss of engine power for undetermined reasons. Contributing to the accident was the pilot's inadequate preflight weight and balance planning and his aggressive low altitude maneuvering, which resulted in an aerodynamic stall and loss of control" .

Where the accident could have been prevented

Two pilots, one with about 9,000 hours, flew a running engine for a mile at 300 feet. Each decision below is listed with its PAVE category and the safe decision the pilot could have made at that point.

A

The engine stopped on the taxiway and restarted itself. On the takeoff roll it surged. The pilot continued the takeoff.

The safe decision: an engine that quits on the ground does not fly until someone knows why. A surge on the takeoff roll is a reason to abort while runway remains, and the pilot briefs the abort point before the roll. The manual's first line for a power loss during takeoff is to land straight ahead if runway remains.

P

Airborne at 300 to 400 feet, not climbing, the airplane turned toward the Bonanza to join up and flew a mile.

The safe decision: partial power at 300 feet is an engine failure that leaves some thrust. The pilot holds the airplane straight ahead, or nearly so, at best glide. The pilot chooses a field in the 60 degrees in front of the nose. A mile of level flight at 300 feet used the only altitude the airplane had for the photo flight.

A

At 300 to 400 feet, a mile out, the airplane turned hard right for the runway. The turn back needed more than 180 degrees, a descent, and a runway threshold 440 feet beyond the point where the airplane stalled.

The safe decision: below the briefed turnback altitude, the pilot lands ahead. The handbook's arithmetic for a 300-foot failure ends more than 1,000 feet below the runway. A steep gliding turn raises the stall speed while the airspeed falls. A landing in the field ahead, at best glide with partial power, was survivable. The turn back to the runway was not.

A

In the turn, 80 to 90 degrees off the runway heading, the nose dropped. The photographs show a nose-up input at the end.

The safe decision: at the stall warning in a gliding turn, the pilot lowers the nose and levels the wings. The distance to the ground does not change that action. An airplane flown into the ground under control at a low speed is survivable. An airplane that stalls at 300 feet is not.

✕

4:08 in the afternoon. Right wing down, nose low, 440 feet short of the threshold. Two dead.

The engine still produced about 2,125 rpm at impact. The airplane could fly to a field. It could not fly through a steep turn at 300 feet.

The pilot chooses the field high and keeps the choice low. The handbook's three factors for the approach are "wind direction and velocity, dimensions and slope of the chosen field, obstacles in the final approach path," and "these three factors are seldom compatible. When compromises have to be made, the pilot should aim for a wind/obstacle/terrain combination that permits a final approach with some margin for error in judgment or technique" . The pilot judges a field in this order:

The last factor matters after the landing. The first four decide whether there is a landing.

Commit to the field

A late change of field is how a survivable forced landing becomes a stall-and-spin accident. The handbook says: "the pilot should not hesitate to discard the original plan for one that is obviously better. However, as a general rule, the pilot should not change his or her mind more than once; a well-executed crash landing in poor terrain can be less hazardous than an uncontrolled touchdown on an established field" . In training the rule is the same. The handbook permits a change only for "a more advantageous field within gliding distance," and the instructor explains "the hazards involved in these last-minute decisions, such as excessive maneuvering at very low altitudes" . The pilot changes fields early, once, and only for a clearly better field. Below a few hundred feet the pilot does not change fields.

The forced-landing pattern

The forced landing is energy management flown as a traffic pattern. The Warrior's manual says: "When you have located a suitable field, establish a spiral pattern around this field. Try to be 1000 feet above the field at the downwind position to make a normal approach" . The handbook says: "The pilot may use any combination of normal gliding maneuvers, from wings level to spirals to eventually arrive at the normal key position at a normal traffic pattern altitude for the selected landing area. From the key point on, the approach is a normal power-off approach" . The pilot arrives abeam the touchdown point at the planned altitude and flies a normal base and final.

The pilot does not extend flaps until the field is assured: "premature use of flap and dissipation of altitude may jeopardize an otherwise sound plan" . The pilot loses excess altitude by "widening your pattern, using flaps or slipping, or a combination of these" . Too much speed is a separate fault: "Eagerness to get down is one of the most common faults," and "too much speed is just as dangerous as too little" .

Conditions change the plan

Four conditions change what a good field is:

At high density altitude the true airspeed is higher for the same 85 on the dial. The glide covers the same ground for each foot, but faster, and the landing roll is longer. Gusts require a margin above 85 on final. A gust that drops the airspeed at 200 feet leaves the pilot no throttle to recover with.

A pilot landing into a low sun cannot see the wires on the field. A landing on water is a ditching, which the handbook lists as its own kind of emergency landing . The pilot reads the conditions before choosing the field, not after.

An engine failure on the takeoff roll means an abort. The manual says: "If sufficient runway remains for a normal landing, land straight ahead" . The handbook says: "In the event a takeoff is rejected, the power is reduced to idle and maximum braking applied while maintaining directional control." The pilot briefs the abort point before each takeoff: "Prior to takeoff, the pilot should identify a point along the runway at which the airplane should be airborne. If that point is reached and the airplane is not airborne, immediate action should be taken to discontinue the takeoff" . The airplane must be at the expected numbers at that point, or the pilot closes the throttle.

After liftoff, low

An engine failure just after liftoff means a landing ahead. The handbook says: "the pilot's first responsibility is to maintain aircraft control. At a climb pitch attitude without power, the airplane is at or near a stalling AOA. At the same time, the pilot may still be holding right rudder. The pilot should immediately lower the nose to prevent a stall while moving the rudder to ensure coordinated flight. The pilot should establish a controlled glide toward a plausible landing area, preferably straight ahead" . The manual's instruction when no runway remains: "maintain a safe airspeed and make only a shallow turn if necessary to avoid obstructions" . The pilot lands within about 30 degrees either side of the nose. The pilot accepts obstacles, and the handbook says why: "a collision with obstacles at the end of a ground roll or slide is much less hazardous than striking an obstacle at flying speed before the touchdown point is reached" . The pilot does not accept a stall.

The impossible turn is a briefed altitude

The turn back to the runway depends on a briefed altitude, not on instinct. The handbook names the turn: "Turning back to an airport after a low-altitude engine failure, also known as 'the impossible turn,' presents many challenges, and a pilot who attempts to turn back without due consideration and training will need considerable luck to prevent disaster" . The FAA's arithmetic for a failure at 300 feet uses:

At the end of that turn "it has descended 1,316 feet placing it 1,016 feet below the runway." A steeper turn loses less altitude and raises the stall speed. The handbook's conclusion: "A turn back at low altitudes presents an unacceptable risk for student pilots, low-time pilots, untrained pilots, pilots without adequate proficiency, and pilots flying airplanes with insufficient glide performance to return to the field," and "the pilot should not attempt a turn back unless a successful turn back will result" .

The pilot briefs a turnback altitude for the airplane, found with an instructor at a safe altitude. Below that altitude the pilot lands ahead. The turn is more than 180 degrees, because the airplane ends up beside the runway and must realign. The turn costs hundreds of feet.

Load factor in the gliding turn

Load factor makes the gliding turn back fatal. The Pilot's Handbook says: "the load factor increases at a terrific rate after a bank has reached 45° or 50°. The load factor for any aircraft in a coordinated level turn at 60° bank is 2 Gs." The handbook adds: "an aircraft's stalling speed increases in proportion to the square root of the load factor. This means that an aircraft with a normal unaccelerated stalling speed of 50 knots can be stalled at 100 knots by inducing a load factor of 4 Gs" . In the turn back the pilot steepens the bank to reach the runway, which raises the stall speed. At the same time the pilot holds the nose up to stretch the glide, and the airspeed falls. The stall speed rises to meet the airspeed, and the airplane stalls in a bank a few hundred feet up.

The handbook's list of consequences of the desire to save the airplane begins with "making a 180° turn back to the runway when available altitude is insufficient" . The Cardinal at Lake Placid followed that arithmetic.

Once the landing is assured, the pilot secures the airplane. The handbook says: "Deactivation of the airplane's electrical system before touchdown reduces the likelihood of a post-crash fire. However, the battery master switch should not be turned off until the pilot no longer has any need for electrical power to operate vital airplane systems." The handbook adds: "it is generally better to switch the engine and fuel off just before touchdown" . The Warrior's manual gives the list: "When committed to landing: 1. Ignition - Off 2. Master Switch - Off 3. Fuel Selector - Off 4. Mixture - Idle CutOff 5. Seat Belt tight and Shoulder Harness in place" . The module flies it as:

The handbook's rule over all of these items: "Positive airplane control during the final part of the approach has priority over all other considerations, including airplane configuration and checklist tasks" .

The call

The pilot makes the call when the workload allows. The manual says: "If possible, notify the FAA by radio of your difficulty and intentions. If another pilot or passenger is aboard, let them help" . The AIM's form is MAYDAY three times, on the frequency in use or the emergency frequency. The pilot sets the transponder to 7700 if not already in contact . The message gives these items, as many as time allows :

A controller who hears the call clears the airspace and starts the rescue. The pilot makes the call at 85 MPH with the field chosen, and stops the call the moment the airplane needs both hands.

After the stop

After the stop, the people have priority. Everyone gets out and clear of the airplane, then the pilot confirms the ELT is on. The AIM says the ELT "is activated when it is subjected to crash-generated forces," and the pilot can check it, because "the ELT may be activated by the pilot" if the impact did not do it . Then the group stays with the airplane. A wreck is easier for searchers to see than people walking among trees.

The emergency authority

Section 91.3(b) applies to each of these actions: "In an in-flight emergency requiring immediate action, the pilot in command may deviate from any rule of this part to the extent required to meet that emergency" . The altitude minimums of 91.119 are Part 91 rules, and 91.3(b) overrides them in an emergency. A pilot who glides over a town at 500 feet to reach the only field has broken no rule. The pilot sends a written report only if the Administrator asks for it.

Sources for this module

You are not asked to read these end to end. Have them, and know where in them this module lives. On the checkride you may open the handbook and you may not open this site. Each one links to where you get it. Reading a full chapter is worth it, and it is not required to pass this module.

Your study guide and quiz

The facts to remember are:

Study guide — Module 1-15 (PDF)

Write the quiz answers in full. On the checkride the examiner pulls the throttle at 6,500 feet and asks what you do first. The answer is a number: 85.