#6: Engine Failure (Cruise Flight)1
- #6: Engine Failure (Cruise Flight)1
This exercise seeks to determine if you can maintain aircraft control after you experience an engine failure during cruising flight; you will also be assessed with respect to your ability to manoeuvre the aircraft with one engine inoperative.
At an operationally safe altitude the Examiner will simulate an engine failure and you will be required to identify the failed engine, attempt to rectify the failure, and then simulate or actually feather the failed engine.2
You will also be required to demonstrate your ability to climb at Vyse, descend, and turn into and away from the failed engine using 30°-bank turns.
Throughout this exercise you will be expected to adhere to the following:
- maintain directional control within ± 20°;
- maintain altitude within ± 100 feet of the assigned altitude if the aircraft is capable;
- maintain airspeed within ± 10 knots of the assigned airspeed;
- complete the necessary checks in accordance with the POH.
The “cruise” engine failure is simply one that occurs at a point in the flight where the pilot has time to perform a systematic procedure, in accordance with the POH, to restart the engine. Limited time is not a factor which dominates the pilot response in this exercise—quite unlike, for example, the very much time-limited response the pilot must produce if an engine failure occurs immediately after departure or on final approach, where success is based on the quick identification and feathering of the bad engine. The pilot response in a cruise engine failure focuses firstly on keeping the aircraft under control, and secondly on attempting to restore power to the troubled engine. The POH (p. 3-11) is short and to the point in this respect:
Note: If circumstances permit, in the event of an actual engine failure, the pilot may elect to attempt to restore power prior to feathering. The following actions are suggested:
- Mixture—As Required
- Fuel Boost Pump—On
- Fuel Selector—Crossfeed
- Magnetos—Select Left or Right only
- Alternate Air—On3
As you can see, the actions are not elaborate here, and they should only take a few seconds to complete. If there is time to undertake these actions, then this may be considered a “cruise engine failure.” We can further collapse these five items into a three-category check, which are really applicable to the restart of any aircraft engine:
The point is, of course, that it will not take a lot of time to get a restart happening if a restart is in fact possible.
Let us now take a look at the pilot response to the cruise engine failure in its entirety. We shall go somewhat beyond Piper’s short list to include the list of crucial actions, which must be accomplished to ensure an adequate response to an engine failure in cruise.
This first response—controlling the aircraft—is crucial. You must keep the aircraft straight and level, and you must maintain pitch and altitude control. Your brain must begin to process visual and physical data immediately, and if you complicate the initial pilot response with jerky and erratic control inputs, then you are simply delaying the time required for the brain to make sense of the situation.
The controlled response to an engine failure entails corrections of all three aircraft movements—yaw, pitch, and roll. To begin with, the aircraft will immediately yaw in the direction of the failed engine—this is simply the result of the asymmetric thrust, as the strong engine overpowers its failed sister. The pilot response need not be “instantaneous” or “immediate”—because, if you do this, your feet quite likely end up struggling with the rudder pedals, which simply complicates the situation with yaw oscillations. Instead, let the nose go where it wants—at least initially—and let it demonstrate to you what corrective inputs are required. If the nose swings to the left, right rudder is required, and visa versa. The rudder response should then be smooth but firm, deflecting the rudder with sufficient pressure to square the nose back to the initial heading that was tracked prior to the failure.4 This smooth but firm rudder pressure is critical in determining which engine is giving the trouble.
The next priority is pitch. The loss of ½ of the thrust, and an estimated 80% increase in drag, will inevitably encourage the aircraft to pitch forward and begin a drift downward from its initial altitude, so clearly an increase in pitch will be required to maintain level flight. How much pitch, of course, is the question, and the answer is to hedge your bets with only slight back-pressure. Then periodically cross-check the altimeter, and it will immediately tell you whether more or less back-pressure is required. If the altimeter starts to ease downward, very smoothly increase the pitch accordingly, and visa versa.5
The third and final priority is roll. Initially, simply concentrate on maintaining a wings-level attitude (while you are busy with yaw and pitch control). Almost immediately you will recognize the direction—left or right—that the aircraft nose wants to go. Once this is realized, simply bank—only about 5° to counter this yaw tendency.6 This bank will immediately and effectively lend support to your feet, and the aircraft will begin to fly through the air in a more efficient state.7
Overall, your response should be efficient and methodical; begin to say the engine-out drill out load—don’t be too rushed (but don’t be slow), and don’t let your language get in way of your actions.
During a cruise engine failure, the “power” response must go from right to left, beginning with the mixtures, then the propellers, then the power. The mixtures must go to full rich to guard against the increased temperature demands that will occur with the good engine. The propellers should then be smoothly and gently set to maximum RPM. Finally the power on both engines should smoothly and slowly set to maximum power.8 Throughout this, you should be cross-checking for any deviations in heading and altitude. Your eyes should also examine your ASI. Deceleration is inevitable, but you should not allow the airspeed to drop below 105 MPH; once needle approaches the blue line, you must begin to concede altitude—your performance will inevitably increase as you either rectify the engine’s problem, or feather its propeller.
Obviously, it is unlikely that the gear or flaps will be extended in the scenario of a cruise engine failure, but it must be entrenched in our minds that we automatically respond to an engine failure with a “drag check” immediately after the power-up phase has been completed.
For the “drag” response, physically touch the flaps lever first and the gear switch second—the flaps are the priority as they produce the most drag.
The standard line here, of course, is “dead foot—dead engine.” If we have done our job and used smooth but firm rudder pressure to keep the aircraft straight, this task will be especially easy—one leg will be inordinately inactive.
Take time during the identification to physically tap your dead leg to drive the point home to brain—the one thing you do not want to do is identify incorrectly which engine has failed. As well, as you will see with engine failure during more critical phases of flight, this is not the time to be trying to interpret the tiny engine and power gauges—we will get to these later when we attempt to rectify the trouble.
Because the risk of shutting down the wrong engine during the heat of engine failure is so great—and the consequences of this mis-action so deadly—the verification required here must be accurate.
There are numerous examples in the accident records of flight crews inadvertently shutting down the wrong engine.10 The verification is simply a smooth retarding of the throttle of the suspect engine. There are two obvious responses you will get. If you have selected the correct engine and that engine is dead, the retarding of the throttle will have no effect on flight characteristics; if you have selected the incorrect engine, you will quickly be made aware of this, as the retarding of the throttle will drastically change the flight characteristics of the aircraft. A third response is possible as well, and this is the case when one of the engines has partially failed, so that the retarded throttle will produce a partial change in flight characteristics—here you will have to decide to what extent the partial failure is degrading performance.
The “verification” of the dead engine should be done with a smooth but complete reduction in power to the bad side—you will immediately know if you have identified the correct engine simply by the response to the lever movement. If partial power is indicated, that this must reckoned into your plan of action.11
The “fire check” is next. An immediate shut down may be required by the appearance of pealing and discoloured paint, flames or smoke. This is the crucial “first step” after the verification of a cruise engine failure (note the subtle differences in the departure engine failure), and if it is burning, get the fire stopped immediately. So after you have correctly identified the failed engine, you must visually inspect the nacelle to look for the smoke trail and/or flames. If a fire is evidenced, Piper’s procedures are explicit (p. 3-18):
- Fuel Selector—OFF
- Mixture—IDLE CUT OFF
- Heater—OFF (In all cases of fire)
- Defroster—OFF (In all cases of fire)
- If terrain permits—Land Immediately
Cause and Restart Check
There are two possibilities here—the problem can be immediately rectified, or it cannot be immediately rectified. If it cannot be immediately rectified, the engine’s propeller must be feathered. If it can be rectified, there are only three possible causes—inadequate fuel, spark, or air. With the causes narrowed to three possibilities, there is, in turn, only a limited number of responses the pilot can perform. Under the category of fuel, the electric pump can be turned on, and the fuel tank from the opposite wing can be selected by cross-feeding. There is the remote possibility that variable throttle setting may at least partially rectify the problem. With respect to “spark,” the only possibility is that one magneto has self-destructed—in an attempt to rectify this possible cause, each magneto should be individually and sequentially selected OFF.
Finally, with respect to “air,” we may have the option of selecting the “alternate air,” although this manual selection is not possible in GURW as the alternate air is automatic as a result of the turbocharger modification.
Pretty straightforward here—if the problem is not rectifiable, pull the blue knob—but remember pulling the incorrect blue knob could be deadly. This is a good time to be reminded of the 800-RPM limit on feathering. If the engine speed is reduced to less than 800 RPM, lock pins will prevent successful feathering. In the case of a lubrication problem—loss of oil, for example—there may be a risk of engine seizure prior to reaching the feathering stage, and quick feathering may be the order of the day.
Take care of the good engine
Re-set the power quadrant to settings that are suitable to your circumstances. Don’t overwork the good engine if it is not necessary. Check the temperature of the cylinders, and make the appropriate changes to mixture and cowl flaps. Look after the good engine’s fuel supply and you may want to begin planning for any requirement to crossfeed the fuel.12 Watch very carefully the electrical demand on that one remaining alternator. An indication of 60 on the load-meter indicates that the alternator is being worked too hard, and you must take action to reduce the electrical load before the only remaining good alternator packs in. This consideration is crucial where navigation is dependent on radio aids.
Take care of the bad engine
Quite simple at this point—fuel and alternator are turned off. Ensure the cowl flap is closed.
During the flight test, the Examiner will fail the engine by simply reducing the throttle to idle. During training, the Instructor will make effort to conceal the affected engine.
Unless otherwise advised, all checks or tasks conducted during this exercise must be simulated only. To indicate the completion of a check or task, the items should be physically touched, and the action verbally stated. To select crossfeed for the left engine, for example, you should physically touch the crossfeed selector and state “left engine crossfeed,” etc. There are exceptions to this—all power quadrant tasks should be physically completed, with the exception of feathering the engine. To indicate that you are feathering a propeller, the propeller control lever should be brought back to the ½-setting (halfway between full forward and full back)—this will set the propeller to approximately 2000 RPM, and this is the simulated feather setting. When you eventually act to simulate feathering, it is the Instructor or Examiner’s job to fine-tune the propeller setting to 2000 RPM; the Instructor or Examiner will then advance the throttle of the affected engine, from idle setting to a setting just above the gear horn13—approximately 12” MP. There are other exceptions to the don’t-change-the-settings rule—the gear should be positioned as you would in a real engine failure, and the same applies to the flaps and cowl flaps.
Throughout this exercise there is the risk of inadvertent “eyes in the cockpit,” so be sure to be conscious of vicinity aircraft. It is important to establish a safe “division of labour” whereby you do some activity in the cockpit, then stop and scan for traffic—do some more activity, then again stop and look for traffic.
1 Includes “Manoeuvring with One Engine Inoperative.”
2 It would be unprecedented for an Examiner to ask you to actually feather an engine, although the flight test suggests that this, technically, could be required.
3 Not applicable to GURW, which has a turbocharger modification—with this, the manual alternate air system is replaced with an automatic system—negative pressure in the intake manifold (that would occur in the event of impact icing) automatically opens alternate air hatches mounted on the air-filter housing.
4 Presumably a prominent visual marker was being used, and this should have certainly be backed-up with the positioning of the heading “bug” that appears on the HSI.
5 An experienced pilot looks for “lead” indications on the VSI.
6 If the aircraft yaws to the left, bank to the right, and visa versa.
7 Prior to the 5°-bank, the aircraft longitudinal axis was misaligned with the airflow, creating unnecessary drag—i.e., the aircraft was flying slightly sideways through the air. In practical terms, the bank alleviates the pressure and strain of having to keep the aircraft straight solely with rudder. Additionally, the requirement to bank 5° into the working engine is a condition of certification for light twins—that is, the aircraft single-engine performance figures were established during the manufacturer’s certification with the assumption that the pilot establishes the 5°of bank.
8 By the way, if you briefly look at the power gauges you will see evidence of the failed engine, but be careful as the MP on a dead engine does vary with throttle changes.
9 “Flaps First.”
10 The most famous of these was the 1989 crash of British Midlands Boeing 737-400. After engine trouble, the crew initiated a long uninterrupted descent for an immediate landing. It was only at the bottom of the glide—on short final—that the need for power arose. When they discovered they had shut down the wrong engine—they had misinterpreted the then newly designed engine instrumentation—it was too late. They tried desperately to restart the engine, but ran out of altitude, with 47 killed in the subsequent crash (Macarthur Job, Air Disaster—Vol. 2 (1996, Fyshwick: Aerospace Publications Pry Ltd, p. 173).
11 An engine with partial power should not be shut down until the cause has been properly assessed—the condition, for example, could be caused by a malfunctioning magneto, and is therefore “fixable.” Conversely, even continued partial power may be of use to you in enhancing your “singe-engine” performance. Caution must be given to the possibility that the engine may fail at any time—as for example would be the case with a chronically damaged cylinder, combined with an oil leak (seizure of the engine may be eminent and the propeller must be feathered before the RPM are significantly reduced—see p. 2-4 of the POH regarding “feathering lock.”)
12 A cross-feeding engine is not permitted during landing.
13 The “gear horn” is the horn that sounds in the cockpit when the throttle is closed, but the gear is extend.