Aviation Safety Letter 1/2005

Beware of the 180° Turn Back to the Runway.

Beware of the 180° Turn Back to the Runway.On September 7, 2002, a float-equipped Cessna 172P aircraft, with an instructor and student on board, departed from Lake St. John near Orillia, Ont. The purpose of the flight was to allow the student to practise takeoffs, landings, and simulated engine failures on departure. During the climb following the second takeoff, the instructor simulated an engine failure by pulling the throttle back to idle. The student executed a 180° degree turn as part of a simulated forced approach back to Lake St. John. During this simulated forced approach the aircraft stalled, pitched nose down and crashed into the swampy area along the shoreline. The aircraft came to rest in an inverted position with its nose embedded in the swamp. Fishermen on the lake were able to rescue both occupants from the partially-submerged aircraft. Neither the instructor nor the student was wearing a shoulder harness, and both received serious injuries. This synopsis is based on the Transportation Safety Board of Canada (TSB) Final Report A02O0287.

The aircraft was equipped and certified in accordance with existing regulations. The instructor pilot held a valid Canadian commercial pilot aeroplane licence and a Class 4 instructor rating. The instructor had accumulated 571 flight hours in powered aircraft, 150 of which were on float-equipped aircraft. The instructor pilot occupied the right seat during the occurrence flight. The student pilot held a valid Canadian student pilot aeroplane permit and was taking ab initio pilot training on float-equipped aircraft. The student had accumulated 30.5 flight hours, of which 19.5 were on float-equipped aircraft. The instructor and student had completed two training flights in the week preceding the accident. Circuits and emergencies were the primary focus of these trips. The accident flight was scheduled to allow for further enhancement of these skills and to determine if the student was ready to fly solo.

The instructor conducted an informal pre-flight briefing with the student at the dock and in the aircraft as it was taxiing before the first takeoff. This was common practice at the flight school, and there was no time set aside between bookings for pre- and post-flight briefings. It was assumed by both the instructor and the student that this lesson would be a continuation of the previous day's lesson, which had encompassed takeoffs and landings combined with simulated engine failures. However, all previous simulated engine failures had been introduced at an altitude of at least 1 000 ft above ground level (AGL).

In this instance, the simulated engine failure was introduced during climb out, and the student was not prepared. Directly ahead of the aircraft, the terrain was forested, and the aircraft altitude was not considered sufficient to turn right and land on an adjacent lake, so the student turned back to land on Lake St. John. As the student completed the turn back toward Lake St. John, control of the aircraft was either transferred to the instructor, or the instructor took control. During or subsequent to the transfer of control, the aircraft stalled and descended into the swamp. At no time during the simulated engine failure scenario did either the student or the instructor apply engine power to abort the simulated forced approach.

In its final report, the TSB said there is insufficient guidance provided in either the Transport Canada (TC) Flight Instructor Guide, the TC Flight Training Manual, 4th Edition (Revised), or the Cessna 172 Pilot Operating Handbook for a pilot to determine the minimum altitude required to safely execute a 180° degree turn following an engine failure after takeoff. Page 128 of the TC Flight Training Manual is quoted in the report and says the following:

"Numerous fatal accidents have resulted from attempting to turn back and land on the runway or aerodrome following an engine failure after take-off. As altitude is at a premium, the tendency is to try to hold the nose of the aircraft up during the turn without consideration for the airspeed and load factor. These actions may induce an abrupt spin entry. Experience and careful consideration of the following factors are essential to making a safe decision to execute a return to the aerodrome:

  1. altitude
  2. the glide ratio of the aircraft
  3. the length of the runway
  4. wind strength/ground speed
  5. experience of the pilot and
  6. pilot currency on type."

The Cessna 172 Pilot Operating Handbook (Section 3, Engine Failures) states the following:

"In most cases, the landing should be planned straight ahead with only small changes in direction to avoid obstructions. Altitude and airspeed are seldom sufficient to execute a 180-degree gliding turn to the runway."

The TSB further states in its report that although these documents recognize the inherent dangers associated with a 180° degree turn following an engine failure, they do not address the process by which a pilot or a student can determine the minimum safe altitude for an engine-out turn back. The TSB quotes the TC civil aviation document TP 13748E, An Evaluation of Stall/Spin Accidents in Canada 1999, which discusses the need for clear and concise information regarding the altitude required before an engine-out 180° degree turn is initiated. TP 13748E states in part:

"Turn Back After Takeoff - Several stalls occurred when the pilot decided to turn back to the runway when the engine failed. Typically, guidance on this topic recommends that the pilot land straight ahead unless the aircraft has enough altitude to make the turn back to the runway. This constitutes a "fuzzy rule." That is, the rule requires interpretation, but the rule provides little or no guidance in making that interpretation. How much altitude is enough? Is it always the same? What variables may affect the requirement? The pilot is better off not having to consider these questions. Lives would be saved if the guidance required no thought or assessment. If an engine failure after takeoff results in an accident, the pilot is at least eight times more likely to be killed or seriously injured turning back than landing straight ahead. The easiest decisions to make are those which are prescriptive. As soon as the situation is known to exist, the procedure to follow is defined. Engine failure after take off should be such a decision."

TSB Analysis - The lack of communication between the instructor and student was problematic. The informal pre-flight briefing did not prepare the student for an engine failure shortly after takeoff and, contrary to the recommendations in the Flight Training Manual, did not provide full consideration of the factors essential to making a successful turn back.

The student pilot was able to complete the 180° degree turn, which put the aircraft in a downwind approach to the lake; however, the aircraft at that point was both low enough and slow enough that a successful forced landing was not assured, and it was necessary for the instructor to take control of the aircraft. Due to the lack of preflight planning for this exercise, the instructor was not prepared for the dangerous situation that had quickly developed and, consequently, tried to salvage the forced landing rather than apply power to execute an effective abort procedure.

TSB findings as to cause and contributing factors

  1. The instructor allowed a dangerous situation to develop and continue until the aircraft stalled at an altitude from which recovery was not possible.

  2. Neither pilot wore the available shoulder harness, which likely contributed to their degree of injury.

TSB findings as to risk

  1. Although the TC Flight Training Manual, 4th Edition (Revised), recognizes the inherent dangers associated with a 180° degree turn following an engine failure, it does not provide sufficient guidance for a student or an instructor to determine the minimum safe altitude for a 180° degree turn back to the take-off area in the event of an engine failure or simulated engine failure after takeoff.

  2. The training flight was conducted without a detailed formal pre-flight briefing. Therefore, the student was not fully aware of the expected actions following a simulated engine failure at low altitude, increasing the risk that errors could be made.

We agree with the finding related to the immediate factor that led to this occurrence, but we are concerned about the TSB's suggestion that there is a need for specific guidance for a student or an instructor to determine the minimum safe altitude for a 180° degree turn back to the take-off area in the event of an engine failure or simulated engine failure after takeoff.

While the statement itself in the TSB finding is correct, the implication is not. TC is well aware of the risk of attempting to make a turn back to the take-off area after an engine failure at low level and notes that all references in TC flight training manuals and manufacturer's training manuals advise against this technique and recommend landing straight ahead. The regulations also clearly state that the Flight Instructor Guide and the Flight Training Manual must be consulted together to deliver a comprehensive training program. The Flight Training Manual provides clear general guidance related to this type of manoeuvre when it states that here are many factors involved in determining a safe altitude for a 180° degree return for landing, and it requires a high degree of skill to attempt such a manoeuvre under what would be considered a high-stress situation. This is an area of training that would be developed progressively over time with a student, taking many factors into account.

It must also be emphasized in the analysis of this and other occurrences that the hazard is not the decision to simulate an engine failure at low altitude, but it is the pilot's attempt to make a 180° degree turn. In this specific case, the instructor pilot allowed the student to commence a turn and delayed taking control of the aircraft. The simulation of an engine failure on takeoff is to test the pilot's decision-making skills and once this is determined, there is no need to attempt or continue a turn at an unsafe altitude. There is no need for a minimum altitude restriction if it is understood that no attempt at a turn under these circumstances is acceptable in a training sequence. Therefore, this accident illustrates more the need for close supervision of the techniques and procedures involved in flying training organizations, rather than establishing arbitrary guidelines for a known unsafe manoeuvre.

Nevertheless, while not mentioned in the TSB Final Report, TC does have additional guidance on this issue. Stall/Spin Awareness - Guidance Notes - Private and Commercial Pilot Training (TP 13747E), details an instructor demonstration, at altitude, of a return to the runway after an engine failure after takeoff. The section "Stall Training" contains the following paragraph:

"Engine Failure after Take-off (followed by an attempt to return to the runway)

This demonstration will show the student how much altitude the aeroplane loses when, following an engine failure after take-off, an attempt is made to return to the departure runway. In order to complete the manoeuvre, the aircraft must be turned to a reciprocal heading AND realigned with the runway. This requires much more than just 180 degrees of turn. For novice pilots, turning back is not an option. An evaluation of stall/spin accidents in Canada showed that the pilot is eight times more likely to be killed or seriously injured turning back than landing straight ahead. For expert pilots who know how much altitude is needed to complete the required manoeuvring, it can be an option but even experts should be looking for landing areas that require less manoeuvring and less risk. Perform this demonstration using either a medium or steep bank in the turn, giving emphasis to stall avoidance.

Instructor and Student Practice

At a safe altitude,

  1. In cruise configuration, establish the best rate of climb speed (Vy). Note your altitude.

  2. Reduce power smoothly to idle to simulate the engine failure.

  3. Lower the nose to maintain the best glide speed and make a 270° turn followed by a 90° turn in the opposite direction to roll out on the reciprocal of the original heading.

  4. Point out the altitude loss and emphasize how rapidly airspeed decreases following a power failure in a climb attitude.

  5. Demonstrate the manoeuvre again and allow the aeroplane to stall during the turn. (This is actually a variation of an approach stall.) Emphasize the possibility of a spin developing from these types of stalls.

Note:  It should be stressed that the successful return to the airport after an actual engine failure on take-off depends on a variety of factors including available landing surfaces, altitude AGL when failure occurs, weather, turbulence, aircraft type and pilot skill and stress level. Point out that the altitude loss incurred during the controlled demonstration will be significantly less than in a real life situation. It is recommended to conduct the demonstration from the cruise configuration to reduce wear on the engine."

In conclusion, we wish the report had focused more on the human and organizational factors that led to the occurrence, rather than the perceived lack of prescriptive guidance on how to perform a known dangerous manoeuvre. - Ed.

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