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djpacro

Aerobatics in the Chipmunk

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An excellent set of notes for spinning and aerobatics in the Chipmunk.

 

http://www.waypoints.co.nz/media/pdf/aerobatics-manual-dch-1-chipmunk-master-first-edition.pdf

 

I see that the diagrams at least were extracted from local author Robert Bowring's book "Flying AEROBATICS" (long out of print).

 

 

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The ATSB report on a Chipmunk aerobatic/spin accident has just been released. The pilot and passenger were very lucky to have survived.

 

I can't think of words critical enough of the flying school and the relevant instructors without being libellous.

 

"At the top of the loop, the aircraft stalled while inverted, most likely as the result of excessive elevator input. The aircraft rolled and entered an upright spin, which became flatter as it developed. Later, the pilot reported that attempts to recover were unsuccessful. The spin continued until the aircraft impacted terrain. The pilot and passenger sustained serious injuries and the aircraft was seriously damaged. There was no fire.

 

The pilot reported undertaking training to conduct loops, but there was no record of an endorsement and the instructor did not recall approving the pilot to conduct loops. As a result, at the time of the accident, the pilot likely did not possess the necessary skills and judgement to conduct the manoeuvre safely and consistently.

 

The pilot probably did not apply and maintain the spin recovery control inputs appropriate for a fully-developed spin in a Chipmunk aircraft. Furthermore, the pilot was taught a spin recovery method that was not effective for recovering from such spins in the aircraft.

 

In addition, the accident aircraft’s flight manual had not been approved by the Civil Aviation Safety Authority and did not include advice on spin recovery. The mandatory, Civil Aviation Safety Authority-approved flight manual contained spin recovery advice.

 

The flying school that provided the pilot’s aerobatic training reported that a briefing process was undertaken with all current aerobatic instructors to ensure that consistent terminology is used to describe and teach aerobatic manoeuvres. It also reported that a programme of standardisation flights for all current aerobatic instructors will include the training of spin and unusual attitude recovery for aerobatic students.

 

Safety message,

 

Pilots and instructors, particularly those intending to conduct or teach aerobatic manoeuvres, should be familiar with any special handling requirements for a particular aircraft type as well as recovery from both incipient and developed spins. Furthermore, they should ensure that they hold the appropriate aerobatic endorsement before attempting a manoeuvre."

 

Nope, that should be "must" not "should". CASA only requires spin instructors to know the spin recovery method for the type they are trained in, plus know Beggs-Mueller - and teach the spin recovery method applicable to the type they train in - per the AFM. The instructors did not know the required spin recovery method for the Chipmunk per the AFM.

 

"Contributing factors

 

• The pilot attempted to conduct a loop without the required qualification.

 

• The aircraft entered an upright spin after a stall or flick-roll at the top of an attempted loop.

 

• The pilot probably did not apply and maintain the spin recovery control inputs appropriate for a fully-developed spin in a Chipmunk, and the spin continued until impact with terrain.

 

Other factors that increased risk

 

• The flight instructor who taught the pilot spin recovery did not teach the method to recover from a developed spin that was appropriate for the aircraft type.

 

• The spin recovery methods taught by the flying school were inconsistent across instructors and training material, and were not always appropriate for the Chipmunk aircraft type used by the school. [safety Issue]

 

• The approval for the accident aircraft’s flight manual had been revoked, and the flight manual in use lacked the spin recovery instructions that would have been present in a flight manual issued by the aircraft type design organisation.

 

• The flying school’s Chipmunk aircraft was used for aerobatic instruction and endorsement without having a current, approved flight manual that contained spin recovery instructions."

 

See the full report at:

 

http://www.atsb.gov.au/publications/investigation_reports/2014/aair/ao-2014-114.aspx

 

 

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An excellent set of notes for spinning and aerobatics in the Chipmunk

An excellent document, thank you for sharing.

 

The Chipmunk is a lovely aeroplane to fly, aerobat and spin. You just need to follow the manufacturer's spin recovery technique and should be exposed to miss-handled manoeuvres during aerobatic training / checkout.

 

 

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Recommending the application of FULL forward stick is inconsistent with any concept of a "hands off " recovery (on the stick) that works for most aircraft. Also, Applying full forward stick (to the stop) may result in entering an inverted spin. That point should be emphasized, though I think it does get a mention. You have to be ready to centralise controls at the point recovery has been achieved, fairly quickly, as your speed is increasing fast.

 

Usually the loop is about the first aerobatic manoeuver that was taught. Falling into a spin would have been somewhat unexpected, and probably caused by holding the stick right back. Confusion can easily set in if you haven't mentally prepared yourself in these situations. Deciding whether spin or spiral is determined by AIRSPEED indication. Something you must be clear about, because the recovery is different. You don't have a lot of time to do the right action(s).Nev

 

 

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Recommending the application of FULL forward stick is inconsistent with any concept of a "hands off " recovery (on the stick) that works for most aircraft. Also, Applying full forward stick (to the stop) may result in entering an inverted spin. That point should be emphasized, though I think it does get a mention.

I was taught / teach in an upright spin to "progressively ease the stick forward until the rotation stops, then centre the rudder, level the wings and ease out of the dive". The Piper Tomahawk AFM says something like rapidly apply nose down elevator. The Yak 50/52 will quickly transition into an inverted spin if you maintain forward stick after rotation ceases. The moral of the story is to follow the manufacturers published recovery!

 

 

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It seems to me that the Beggs-Mueller hands-off technique is sometimes promoted without due regard for its limitations. Beggs has provided a fairly short list of types on which he states that it works and a shorter list of types where he states that it does not work in some spin modes. Beggs conducted substantial spin tests on a variety of types with different spin modes and published the information. If anyone promotes the technique for other types I always ask to see the evidence.

 

The AFM for my Decathlon clearly states that the hands off technique is inadequate, Beggs also explains that yet one instructor maintains that it works despite not having flown the type nor otherwise obtaining evidence. One instructor used to teach Begg-Mueller in a Decathlon until one student encountered one of the spin modes where it does not work.

 

The technique originated with Mueller who stated that it "worked with all aircraft whose tail configurations were of a certain type: the low mounted tailplane set forward of the rudder ...". There were many types that Mueller did not test and Beggs filled in some (only some) of the blanks. Interesting that the Chipmunk and Zlin 242 do not fit into Mueller's category for which it works.

 

In particular any type where a push is required to move the stick forward is perhaps an indicator that the hands off technique may not work - so the Chipmunk and Zlin 242 etc as examples - both have full forward as a requirement if necessary. It is fairly easy to get a Decathlon and Cessna Aerobat in a situation where a push is required to move the stick/yoke forward.

 

Extract from one of Beggs'articles:

 

SpinOffsBeggs2extract.png.cc7737b57fcb65e602e9d5463a0a583f.png

 

Decathlon and Pitts S-1/S-2 will happily transition to inverted with brisk simultaneous rudder and full forward stick.

 

(note that I am only referring to fully developed spins here)

 

 

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Confusion can easily set in if you haven't mentally prepared yourself in these situations. Deciding whether spin or spiral is determined by AIRSPEED indication. Something you must be clear about, because the recovery is different. You don't have a lot of time to do the right action(s).Nev

Set in for me alright! Great lesson from Roger Pitt, my instructor.

 

 

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