PPRuNe Forums - View Single Post - DHC Beaver down in Hawkesbury
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Old 10th Jan 2018, 02:05
  #209 (permalink)  
fdr
 
Join Date: Jun 2001
Location: 3rd Rock, #29B
Posts: 2,956
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i strongly recommend you get some training in this, or complete an advanced Aircraft control course.
The Beaver accident will be well analysed by ATSB, and they will come to appropriate conclusions based on the information available. My following comments are not related to the Beaver event, they are specifically related to the comment that turn-back training is "suggested" by a poster

UL, apparently you have an aircraft of some type [unspecified, but presumably not a DHC2 on Edo's] that permits you to do with your skill level, recency and training a low level return to departure. Great. That capability, if so, is very specific to the aircraft type that you are operating, the skill and recency you have, and the conditions that may exist at the time of an event.

History is replete with examples of events that ended badly doing that manoeuvre. Suggesting that someone else should get training on that, against recommendations by the manufacturers, approved training programs, regulators, accident investigation bureau findings, and without knowledge of the aircraft type concerned is "courageous". What is apparently easy enough to be suggested to others with your aircraft will probably not match the capabilities of the aircraft or the pilots that you suggest take such training.

The aircraft characteristics of wing loading, drag polar power off, excess thrust, load, CG, roll rate, HQ, stall recognition etc will determine whether such a manoeuvre is feasible. After that, the level of training, recency, wind vector, obstacles, runway geometry will determine whether such a procedure if feasible, is an acceptable risk on the day. One of my 17 aircraft types I own I have specific operating procedures to permit a turn-back manoeuvre, and that is only acceptable on specific runways, following a specific procedure, and when particular energy levels have been achieved. That comes from flying with cold ejection seats. The same aircraft type I originally trained in 40 years ago, and at least then the seats were hot. My other high performance military aircraft, I would never plan on a turn-back, the aircraft performance cannot achieve one, an engine out landing is only going to work from being at low key or better with appropriate energy state and geometry to the runway. Other pilots talking about a turn-back will be removed from the cockpit. I don't mind losing an aircraft, I do mind losing friends.

The Part 23 aircraft generally do not have characteristics that permit a safe turn-back to be contemplated prior to a turn after takeoff. Most experimental aircraft also have inadequate performance to do so, those with high energy tend to also have high wing loadings, and that gives a high stall speed in the turn, and a high sink-rate engine out. Adding high drag count devices is not making it easier.

There is no certification basis to support a turn-back for a Part 23 Subpart B, or indeed any other Part aircraft. The performance data is not available, so in your procedure, you are a test pilot by choice.

§23.2105 Performance data.
§23.2110 Stall speed.
§23.2115 Takeoff performance.
§23.2135 Controllability.
§23.2145 Stability.
§23.2150 Stall characteristics, stall warning, and spins.


In cruise flight, the ability to manoeuvre is a function of height and speed, and the characteristics of the aircraft concerned. What a pilot does on the day should be as smart as possible, you may not get a chance for repeats. In low energy states, keeping it simple and ensuring control is maintained until the structure starts deforming has historically been a sound tactic.

Good luck.
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