System

The {{entity:Kids Remote Control Airplane}} decomposition project ({{hex:DEC81008}}) entered validation this session at 166 requirements across 7 documents: 14 STK, 12 SYS, 29 SUB, 22 IFC, 82 VER, 7 ARC. All six subsystems — {{entity:Propulsion Subsystem}}, {{entity:Flight Control Electronics}}, {{entity:Radio Transmitter}}, {{entity:Power System}}, {{entity:Airframe Subsystem}}, and {{entity:Ground Charging System}} — are marked complete in the spec tree. DECOMP_STATUS was qc-reviewed entering this session.

Verification Audit

Sampling across the 82 existing VER entries confirmed strong coverage of SUB and IFC requirements. VER-REQ-001 through VER-REQ-082 cover all 12 SYS requirements (VER-073 through VER-082 plus scattered earlier entries) and 29 SUB requirements with specific bench test criteria — optical tachometer, oscilloscope, load-cell stand, variable bench supply. VER quality is adequate: quantified pass criteria, listed instrumentation, stated tolerances.

The critical gap: only two of the 14 STK requirements had direct verification entries ({{stk:STK-REQ-001}} via {{ver:VER-REQ-036}}, {{stk:STK-REQ-002}} via {{ver:VER-REQ-037}}). STK-REQ-003 through STK-REQ-014 were verified only through intermediate SYS and SUB requirements — the STK-to-VER trace chain was broken. For regulatory and safety requirements with legal force (EN 71, ASTM F963, FCC Part 15, CE RED, UAS registration), that indirect chain is insufficient for a product safety file.

Scenario Validation

Four ConOps scenarios checked against the STK trace chains:

Scenario 1 — First flight by an 8-year-old. {{stk:STK-REQ-001}} → {{ver:VER-REQ-036}} (user trial, 5 children aged 8-14). {{stk:STK-REQ-002}} → {{ver:VER-REQ-037}} (novice pilot trial, 30-minute learning criterion). Chain complete.

Scenario 2 — Battery charging by a parent. {{stk:STK-REQ-004}} had no direct VER. Gap closed: {{ver:VER-REQ-084}} added (per-cell monitoring, thermal cutoff, fault alarm test). {{stk:STK-REQ-003}} parent pre-flight check gap closed: {{ver:VER-REQ-083}} (parent pre-flight demonstration, 5 trials, 60-second criterion).

Scenario 3 — Control link loss at range. {{stk:STK-REQ-006}} had no direct VER. Gap closed: {{ver:VER-REQ-086}} added (flight demonstration at 20m/50m, motor cut within 500ms, controlled glide trajectory, land within 30m). This complements the bench-test {{ver:VER-REQ-007}} which only validates the 500ms timing.

Scenario 4 — Retail sale and regulatory compliance. {{stk:STK-REQ-009}} (EN 71/ASTM F963), {{stk:STK-REQ-014}} (FCC Part 15/CE RED), and {{stk:STK-REQ-012}} (labelling) had no direct VER entries. These are legal requirements requiring third-party certification evidence. Gaps closed: {{ver:VER-REQ-089}} (accredited lab certificate), {{ver:VER-REQ-094}} (radio type approval certificate), {{ver:VER-REQ-092}} (label inspection against EN 71 Annex A checklist).

Mode Coverage

Normal flight, degraded-wind ({{stk:STK-REQ-013}} → {{ver:VER-REQ-093}} crosswind flight demonstration at 14–16 knots), failsafe ({{stk:STK-REQ-006}} → {{ver:VER-REQ-086}}), charging, and ground-handling modes all now have direct STK verification. Mass compliance ({{stk:STK-REQ-010}} → {{ver:VER-REQ-090}}, three-sample test for 250g UAS exemption threshold) was missing and added.

Safety Argument

H-001 (uncontrolled flight): covered by {{sys:SYS-REQ-004}} → {{sub:SUB-REQ-027}} → {{ver:VER-REQ-076}} (bench failsafe test) and {{stk:STK-REQ-006}} → {{ver:VER-REQ-086}} (flight demonstration). SIL 1 tag consistent through chain. Safe state (motor cut, glide descent) is reachable and verified.

H-002 (LiPo thermal runaway): covered by {{sys:SYS-REQ-005}} → {{sub:SUB-REQ-015}} → {{ver:VER-REQ-077}} (charger over-voltage and thermal test) and {{stk:STK-REQ-004}} → {{ver:VER-REQ-084}} (direct stakeholder-level charging safety test). SIL 2 tag consistent. Safe state (charge termination, audible alarm) now has both system-level and stakeholder-level VER.

flowchart TB
  RP[Propulsion Subsystem]
  FC[Flight Control Electronics]
  RT[Radio Transmitter]
  PS[Power System]
  AF[Airframe Subsystem]
  GC[Ground Charging System]
  RT -->|CPPM/PWM control| FC
  FC -->|Throttle PWM| RP
  FC -->|Servo PWM| AF
  PS -->|7.4V LiPo| RP
  PS -->|5V BEC| FC
  GC -->|Balance charge| PS

Cross-Domain Findings

Semantic search on “motor failsafe cutoff brushless” returned Electromagnetic Brake ({{hex:D6D51018}}) from the elevator domain — spring-applied fail-safe engagement, 150ms response. That design pattern (fail-safe by spring engagement, not by software command) is not applicable to RC aircraft but confirms the ESC motor-cut approach is the correct analogous pattern for powered flight.

Motor Drive Electronics ({{hex:D1F53018}}) from the AUV domain — over-current protection, thermal monitoring. Analog confirms thermal monitoring is covered under the ESC; confirmed by {{ver:VER-REQ-046}} (ESC thermal test at 75% throttle).

The esc entity in the graph had hex code 00000000 — an unclassified abbreviation artifact. Classified proper entity Electronic Speed Controller at {{hex:D4F57218}} ({{trait:Physical Object}}, {{trait:Powered}}, {{trait:Processes Signals/Logic}}, {{trait:System-Integrated}}, {{trait:System-Essential}}). Acknowledged Biological/Biomimetic false-positive on {{entity:Kids Remote Control Airplane}} — aviation corpus artifact, no biocompatibility requirements apply.

Gaps Closed

12 direct STK verification entries added ({{ver:VER-REQ-083}} through {{ver:VER-REQ-094}}), covering every STK requirement with a distinct verification method: user trials for usability (STK-001/002), demonstration tests for safety behaviours (STK-003/005/006/008/013), bench tests for electrical safety (STK-004), mass measurement (STK-010), packaging inspection (STK-011), and third-party certification for regulatory requirements (STK-007/009/012/014). 7 ARC orphans remain — accepted as informational architecture decisions not requiring trace links.

Next

Validation pass complete. All 14 stakeholder requirements are directly verified. All 12 system requirements are verified. VER count is now 94 across 178 requirements. Remaining 7 orphans are ARC entries tagged informational. Lint false positives acknowledged. The project is ready for SE_REVIEW to confirm completeness before marking the system validated.