Can ailerons control a broken cable on 1/3 flaps?

[Ernie Martin]

The just-released Special Airworthiness Information Bulletin CE-13-27 reports of a broken flap cable on approach where the pilot was unable to retract the other flap, and had to control the aircraft using full opposite aileron. Point being that retracting flaps may not help if a cable snaps. For lengthy runways, you may wish to consider a new normal of only 1/3 flaps if you are worried about this issue.

Ernie

[hharney]

400 series Cessna's

Here's the file referenced above

[Ernie Martin]

SAIB CE-13-27 relates to "Flight Controls – Frayed Flap Extend Cables". Its main purpose is "to remind owners and operators of any airplane with cable-driven flight controls of the importance of adhering to existing inspection procedures" (emphasis added by me). While it "focuses" on 400 Series Cessnas, it "applies to the entire flight control system on any airplane model with cable driven flight controls". And its report that a pilot was unable to retract a flap after the uncommanded retraction of the other flap due to a broken cable is worth mentioning.

Ernie

[Skymaster337B]

Also interesting to note that the pilot was able to control the aircraft with an asymmetric flap condition...it is probably required from an engineering perspective to be designed that way.

[JimC]

Originally Posted by Skymaster337B

Also interesting to note that the pilot was able to control the aircraft with an asymmetric flap condition...it is probably required from an engineering perspective to be designed that way.

Nope, see above. It doesn't have to be designed that way, but on most GA aircraft it will naturally be that way as part of the average design that makes the ailerons typically not less than 1/2 the flap span. I imagine as you get into more complex systems like the DHC-7 (very large flaps, small ailerons) or the MU-2 (no ailerons at all) that you may get into uncontrollable conditions with an asymmetric flap deployment.