The Tower That Looked Fine from the Road
Rust on a lattice tower leg doesn't propagate uniformly. The face visible from the access track — the one the line walker sees from a vehicle — can show no significant corrosion while leg D, facing into the prevailing weather and shaded from direct observation, is losing section thickness at the base plate. The ACD (anti-climbing device) on that leg, corroded through at the lower mounting bracket, falls during the next high-wind event and takes a length of aerial bundled conductor with it.
The four-leg documentation protocol in this template exists precisely because uniform inspections don't find non-uniform failures.
Route and Tower Identification: The Asset Address
The Tower field is a calculated field: it concatenates Route + Tower Number + Number Suffix into a single identifier — for example, "GZLA 147A" for leg-variant towers, or "ZDC 089" for a standard numbered structure. This auto-generated ID matches the tower's tag number on the physical structure and on the line diagram, which means the inspection record can be retrieved by the same identifier used by the design office, the maintenance scheduler, and the operations center.
Route is a choice field (GZLA, ZDC, DEMO) tied to specific transmission corridors. Filtering by Route groups all towers on a single line for a route-level condition assessment — the view the line owner needs to prioritize maintenance resources across the network. Suite and Extension capture secondary location identifiers for towers at sub-stations, compound installations, or branch points where the primary route + number system doesn't resolve to a single structure uniquely.
Legs A, B, C, D: The Inspection That Actually Walks the Structure
Four image fields — leg A, B, C, D — and four corresponding face overview photos (AB, BC, CD, DA) produce a 360-degree photographic record of the tower. The face overviews capture the full panel span between adjacent legs; the leg photos capture the base plate, step bolts, and lower section where corrosion, impact damage, and section loss are most likely to occur first.
Step leg A Comments and Step leg C Conditions (the naming asymmetry suggests iterative template development) provide text fields for observations that photos don't fully capture: loose bolt count, paint failure extent, weld crack location, deflection measurement from vertical. The distinction between a photo that shows rust discoloration and a comment that records "section loss estimated at 15% of flange thickness, recommend ultrasonic thickness measurement at next scheduled access" is the difference between a documentation record and an engineering assessment.
ACD Condition: The Safety Feature That Fails Silently
ACD condition and ACD photo address the anti-climbing device specifically because ACD failures are silent — the device appears present until it's not secured, and a missing or corroded mounting puts the liability for unauthorized climbing incidents entirely on the infrastructure owner. In jurisdictions with strict tower safety requirements, ACD inspection is a regulatory compliance item, not an optional survey category.
An inspection record that documents "ACD present, lower bracket corroded, upper bracket secure, both locking pins in place" with a photo that shows the device in position is the evidence file for the next audit. One that documents "ACD lower bracket missing" with a dated GPS-stamped photo is the work order that triggers emergency repair before the next scheduled maintenance window.
Number plate photo captures the tower's physical identification tag — the riveted or welded plate that carries the tower number, route designation, and often the height and year of erection. When this plate is missing, corroded beyond legibility, or shows a number that doesn't match the route records, that discrepancy needs to be in the inspection database before it becomes a field identification problem during a fault response.