FAA Aviation Mechanic General (AMG)Materials, Hardware and ProcessesHard
A technician recovering a vintage aircraft wing selects Grade A cotton fabric per the original type certificate specification instead of a synthetic polyester fabric such as Ceconite. Compared to synthetic fabric, what is the primary practical disadvantage of Grade A cotton covering?
- AGrade A cotton cannot be used with any dope finishing system
- BGrade A cotton has a higher minimum tensile strength requirement, making it heavier
- CGrade A cotton requires no rib-lacing or reinforcing tape
- DGrade A cotton has a shorter service life and is more susceptible to mildew and rot
Show answer & explanationAnswer & explanation
Correct answer: D. Grade A cotton has a shorter service life and is more susceptible to mildew and rot
Grade A cotton fabric, while meeting the minimum tensile strength requirements of the original TSO/specification, is organic and therefore more prone to mildew, rot, and deterioration from moisture and age compared to synthetic fabrics like polyester, which have significantly longer service life and greater resistance to environmental degradation.
Why the other options are wrong
- A. Grade A cotton is finished using the same nitrate/butyrate dope process as other fabrics.
- B. Tensile strength requirements do not make cotton inherently heavier than polyester in this comparison.
- C. Both cotton and synthetic coverings still require rib-lacing and reinforcing tape during installation.
Grade A Cotton Fabric
An organic cotton fabric historically used for aircraft covering, meeting minimum tensile strength standards but more susceptible to mildew, rot, and shorter service life than modern synthetic fabrics.
- Organic fiber, prone to mildew and rot
- Shorter service life than polyester (Ceconite-type) fabric
- Still requires dope finishing system for protection and tautness
Memory trick: Cotton is organic — it can rot like an old cotton shirt in the rain