The guide
Runs in your browser. Each defect is drawn in section.
Where the guidance comes from
Defects. FAA-H-8083-31 Figure 4-97 lists the imperfections with cause, remedy and action: cut head (tools not held properly), excessively flat head with cracks (driven too much), sheet separation (work not held together, shank swelled), sloping head (bucking bar not held firmly, or allowed to slide and bounce), buckled shank (improper rivet length). For every one the action is to replace the rivet. AC 43.13-1B Figure 4-6(c) draws the same faults and adds a rivet too short, plates damaged by the tool, and a head cracked because the material was too hard.
Loose and working rivets. The Handbook: chipped or cracked paint around the heads may indicate shifted or loose rivets; tipped or loose rivets show up in groups of several consecutive rivets, probably tipped the same way; a working rivet moves under stress before it is visibly loose, sometimes shown by a dark, greasy residue or deteriorated paint around the head, and calls for an investigation of the substructure.
Flush rivets that show head slippage in the countersink or dimple indicate sheet bearing or rivet shear failure and must be removed for inspection and replacement.
Worked example
On a wing skin, four rivets in a row have shop heads leaning aft, and the paint is cracked round them.
- Sloping heads: bucking fault, replace each rivet.
- But consecutive heads tipped the same way, with cracked paint, are the Handbook's pattern for loose rivets.
Replace them, and look for what is loading that row before closing up.
Limits — when NOT to use this
- Not an inspection programme. What to inspect, and how, comes from the maintenance manual and the inspection programme.
- Dimensions of the shop head are checked with a gauge; see the shop head calculator.
- Damage beyond the rivet, cracks between rivets or tear-outs, is a repair, not a rivet replacement.
Questions people actually ask
Is a smoking rivet a loose rivet?
The dark ring is fretting: AC 43.13-1B calls the smoking rivet the most common example of fretting corrosion, from metal rubbing on metal. It means the rivet is moving, so treat it as working.
Sources
- FAA-H-8083-31, AMT Handbook — Airframe, Volume 1, Chapter 4, Evaluating the Rivet and Figure 4-97; Chapter 4 inspection of damage — defects, causes and remedies; signs of loose and working rivets; joggled shanks and next larger size.
- FAA AC 43.13-1B CHG 1, Figure 4-6 and par. 6-21 — rivet imperfections drawn; the smoking rivet as fretting corrosion.