Cargair Aztec 18 June 2019

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Donald
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Cargair Aztec 18 June 2019

Post by Donald »

Accidental gear retraction on the takeoff roll

https://tsb.gc.ca/eng/rapports-reports/ ... Q0091.html
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PilotDAR
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Re: Cargair Aztec 18 June 2019

Post by PilotDAR »

Too fast hands.

An Aztec will overshoot just fine with half flaps, and even with full flaps, though less well. If in doubt, leave it alone until there is less criticality.

I hope that the instructor passenger was not intending to retract the gear while on the roll, thinking to myself "Positive rate, gear up.". I hope that the instructor pilot was allowing enough time for the hydraulic system to work as intended. I hope that the pilot instructor did not mix up the knobs.

Since the design of the Aztec, the design requirements have been refined for RG cockpit similarity, the newer requirement reads:
Sec. 23.777

Cockpit controls.

(a) Each cockpit control must be located and (except where its function is obvious) identified to provide convenient operation and to prevent confusion and inadvertent operation.
(b) The controls must be located and arranged so that the pilot, when seated, has full and unrestricted movement of each control without interference from either his clothing or the cockpit structure.
(c) Identical powerplant controls for each engine must be located to prevent confusion as to the engines they control.
(d) Wing flap and auxiliary lift device controls must be located--
(1) Centrally, or to the right of the pedestal or powerplant throttle control centerline; and
(2) Far enough away from the landing gear control to avoid confusion.
(e) The landing gear control must be located to the left of the throttle centerline or pedestal centerline.
But, the Aztec predates that, and for whatever reason, Piper made the Aztec with the flaps and landing gear controls reversed for the pilot's perspective. If the pilot or more to the case, pilot instructor, was more familiar with a more modern RG plane, and not thinking about knob shape, they might have made a hand on control error. It's been a while, but if I recall, the Aztec landing gear selector knob lights up red when the gear is in transit, or otherwise unsafe. With no red indication, and three greens, leave it alone until you're either stopped on the apron, or at least safely airborne!
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rigpiggy
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Re: Cargair Aztec 18 June 2019

Post by rigpiggy »

Same with the beech baron. Came off a month of fire patrol on the beech, got in the navajo, and almost brought the gear up in after landing checks
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pelmet
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Re: Cargair Aztec 18 June 2019

Post by pelmet »

PilotDAR wrote: Thu Mar 04, 2021 3:37 pm Too fast hands.

An Aztec will overshoot just fine with half flaps, and even with full flaps, though less well. If in doubt, leave it alone until there is less criticality.

I hope that the instructor passenger was not intending to retract the gear while on the roll, thinking to myself "Positive rate, gear up.". I hope that the instructor pilot was allowing enough time for the hydraulic system to work as intended. I hope that the pilot instructor did not mix up the knobs.
It almost seems as if the instructor wanted to move the gear handle to neutral so the flaps would retract but accidentally selected the gear up. However, the report starts talking about somotogravic effects making the instructor feel like the pitch attitude was 10° nose-up when in fact, they were still on the runway.

I thought the somotogravic effects were more likely when flying on instruments as compared to when one has the runway lights in view out the window. I have experienced this effect in instrument conditions, not on many takeoffs at night when still on the runway(perhaps someone can tell us if they have ever experienced this effect during the takeoff roll).

In the end....positive rate, then select gear up.

Unfortunately, the TSB is asking the FAA and TC to look into retrofitting thousands of aircraft with expensive modifications.......

"To reduce the number of post-impact fires in impact-survivable accidents
involving existing production aircraft weighing less than 5700 kg, Transport
Canada, the Federal Aviation Administration, and other foreign regulators
conduct risk assessments to determine the feasibility of retrofitting aircraft
with the following:
• selected technology to eliminate hot items as a potential ignition source;
• technology designed to inert the battery and electrical systems at
impact to eliminate high-temperature electrical arcing as a potential
ignition source;
• protective or sacrificial insulating materials in locations that are
vulnerable to friction heating and sparking during accidents to
eliminate friction sparking as a potential ignition source; and
• selected fuel system crashworthiness components that retain fuel.
TSB Recommendation A06-10"


The discussion is here......

https://www.bst-tsb.gc.ca/eng/recommand ... a0610.html

I suspect the modifications would exceed the value of many aircraft.
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