The Dangers of The Departure - Engine-Out

Overview

Losing an engine in a single or even a twin-engine aircraft has always been something that every new or seasoned pilot dreads to have to face. Accidents in aviation are horrible and tragic, but the good side is that each one screams out to educate those that are left to carry on. Situations such as these do not occur that often and are completely survivable if the pilot keeps a cool head and thinks over the problem before acting.

The Engine out Situation

What are your primary concerns as the pilot of an aircraft that loses engine power? Airspeed and your Angle of attack! The first thing that occurs when you lose an engine is the nose of the aircraft wants to drop due to a couple of factors: 1) Reduction in lift caused by the reduced air flow over the wings, 2) The reduction of air hitting the top of the horizontal stabilizer causing the empenage of the aircraft to rise instead of drop. What would be the initial reaction of the unseasoned pilot? Lift the nose to stay in the air. This will do two things: 1) Airspeed will be reduced because of the reduced thrust and increased induced drag, 2) Angle of attack will be increased getting closer to the aircraft's critical angle of attack – closer to a stall. If the aircraft stalls, the pilot will have to react quickly and decisively to keep the total reduction in altitude to a minimum while also trying to break the stall allowing for enough airspeed to achieve a controlled descent, a very difficult maneuver to say the least, especially at low altitudes.

Option #1 – Straight-Ahead Recovery

The moment an engine becomes inoperative the pilot should do one thing only, level the aircraft out of its climb immediately - PUSH THE NOSE DOWN! This will allow the aircraft to achieve high enough airspeeds to avoid a reduction in altitude and reducing the angle of attack to stay away from a likely stall. Stalling an aircraft at low altitudes with no power is one of the worst situations a pilot can find themselves in. The rapid reduction in altitude will take the aircraft to critical altitudes and the breaking of the stall will require a nose down attitude putting the aircraft in an even more critical position.

So, what were to happen if you had an engine out and did the right thing – lowered the nose to achieve best glide and landed straight ahead, just how much time and distance will you have? The table below shows the numbers involved in just this type of recovery.

No wind, Straight Ahead Descent

With a 10 knot headwind, your ground speed will not be as favorable as if there were no wind at all. Your distance traveled will be less but your ability to stay in the air will increase because of the additional increase in lift caused by this same headwind. Your vertical speed will be reduced so your total distance over the ground will actually go up if you keep the same airspeed as with no headwind.

10 Knot Headwind, Straight Ahead Descent

Option #2 - Recovery by 'Turning Back'

When would you feel turning back to your departing runway would be the correct course of action during an engine out situation? There are are a number of factors to think about here, but some of the more obvious are the loss of lift during a turn, the time it will take to make the turn and the increase in stall speed during the turn.

Let's start out with a standard rate turn. To turn 180 degrees, it will take 1 minute to complete the turn back to the runway. Depending on your altitude above the ground, this just may not be possible depending on your rate of descent. Based on the tables shown above, the minimum altitude to just turn and not hit the ground would be 500/400 feet without and with a headwind respectively. During the turn, you will NOT get any closer to the runway than when you began the turn, so you will need additional altitude to just make up the distance flown after lift-off. Normally, you will depart the runway long before its end, so you may get a bonus distance of 1000 – 2000 feet depending on the length of the runway and at what point you left the ground.

This is all well and good, but the point here is the amount of altitude, time and distance that will be sacrificed in trying to turn back to the runway during an engine out situation. These estimates don't even take into account the loss of lift that will be encountered during the turning maneuver which will reduce your time in the air even more. Lets assume you have enough altitude to accomplish your turn back to the runway. As shown in the table below (row #4), this altitude would have to be at least 1000 feet AGL resulting in a time-remaining-in-the-air of 60 seconds assuming we do NOT take into account the loss of altitude or speed caused by the turn itself.

No wind descent

Assuming that the 1 minute turn took your aircraft down to 500 feet above ground level, you would have 2.2 nautical miles left to get back to the lift off point since the turn didn't get you any closer to your point of departure. This estimate also depends on your vertical speed during the climb-out and your distance away from the runway. For example, if you were climbing at 500 feet per minute and the aircraft was climbing at 75 knots indicated airspeed with no wind, the aircraft will be over 2 miles away once it achieved the altitude of 1000 feet AGL. This means, that during the turn back to the runway, you will lose 500 feet in one minute (the time for the turn) and be no closer to the runway after the turn – 2.2 miles. So, even at that altitude, you still will not make it back to your point of departure as shown in the table below (row #3).

No wind descent

But wait! Things get even worse! Normally, you will be departing the airport on the upwind runway. This means that after you turn back to the runway, you will lose some lift because of the tailwind caused by your course reversal. This will result in a decreased airspeed while at the same time increasing your ground speed. However, to stay in the air as long as possible, you will have to increase your airspeed, and with no power and the only way to do this is to lower your nose and increase your rate of descent. So, if you are 2.2 nm away, you must be 2,000 feet high before beginning your turn back to your point of departure assuming a loss of 500 feet during the turn as shown in the table below (row #5).

10 Knot Tail Wind after Turn

All of this data should convey a couple of thoughts to the reader. 1) Turns are your enemy in an engine out situation unless you have adequate altitude the counteract the effects of the turn. 2) Staying in the air is important but only to the point where a stall will not occur and your airspeed will be adequate to get you the furthest over the ground over time (best glide speed). 3) Studying and understanding the affects of aerodynamics in climbs, descents, turns and straight and level flight will give you the ammunition you need to make informed decisions.

Other Options

Many experts in aviation say that turning thirty (30) degrees off of your course will give you more options than just landing straight ahead without compromising adversely your altitude or speed. This author agrees with this since a thirty degree turn will give you sixty degrees left to right more choices of landing areas than if only looking directly in front. The point here is that this will give you more options, something advantageous in an engine-out situation.

Other factors can be present that will not allow a straight-ahead landing such as structures or other ground obstructions at or before your best glide distance. Since airspeed is your friend during an engine out situation, it won't hurt to push the nose of the aircraft down to lose altitude and thus shortening your glide distance so you can safely land before the observed ground obstructions. The moment you pull the nose back up to level from your rapid descent, the airspeed will quickly reduce. Use of flaps can further enhance the slowing characteristics of your aircraft in situations such as this, so don't be afraid to use them when necessary.

In Conclusion

So, what does all of this mean? Numbers and examples can help to convey the story, but what should the pilot do to make the right decisions during an engine out situation?

1. Review your engine out procedures during run up. What will you do if you lose your engine on the ground or in the air?

• If an engine fails during the ground roll, power back to idle and apply brakes and back elevator pressure to enhance your braking possibilities.

• If an engine fails immediately after lift off, nose down and land immediately with power back to idle. Don't wait!

• Note: If you are flying in a twin engine aircraft, reduce power gradually.

• If an engine fails during climb, lower the nose and land straight ahead with power back to idle. If altitude is adequate (1,500 – 2,000 feet AGL), consider turning back to the runway but ONLY if altitude will allow for it. Plan for this contingency by doing your homework.

2. Know the areas around the airport of departure. Just what landing options do you have once an engine does fail, if this does happen. Take a look at the runway environment as you approach a new airport from the air and review your home airport's environment and know what you can do if an engine failure does occur.

3. Unless you have MORE than enough altitude, do NOT turn back to your point of departure. Be conservative here and only use this option if you have much more altitude than you would think you might need.

© Bill Komanetsky 2007, June