System-Level Verification Coverage Closed for Kids RC Airplane

System

Kids Remote Control Airplane ({{entity:Kids Remote Control Airplane}}, {{hex:DEC81008}}), session 492. All 6 subsystems are marked complete in the spec tree. Decomposition status: qc-reviewed. This session identified and closed the most significant open gap in the verification plan: 10 of 12 system requirements ({{sys:SYS-REQ-001}} through {{sys:SYS-REQ-010}}) had no verification entries. Project now stands at 166 requirements across 6 documents.

Decomposition

No new subsystems decomposed this session. The work was gap-closure at system level — the decomposition diagram is unchanged.

flowchart TB
  n0["system Kids Remote Control Airplane"]
  n1["subsystem Airframe Subsystem"]
  n2["subsystem Propulsion Subsystem"]
  n3["subsystem Flight Control Electronics"]
  n4["subsystem Radio Transmitter"]
  n5["subsystem Power System"]
  n6["subsystem Ground Charging System"]
  n7["external USB Power Supply"]
  n8["external Atmosphere"]
  n9["external 2.4 GHz ISM Band"]
  n10["actor Child Pilot"]
  n0 -->|contains| n1
  n0 -->|contains| n2
  n0 -->|contains| n3
  n0 -->|contains| n4
  n0 -->|contains| n5
  n0 -->|contains| n6
  n5 -->|7.4V power| n2
  n5 -->|5V BEC| n3
  n3 -->|PWM throttle| n2
  n4 -->|2.4GHz control frames| n3
  n3 -->|servo deflection| n1
  n8 -->|aerodynamic forces| n1
  n9 -->|shared spectrum| n4
  n7 -->|5V 2A| n6
  n6 -->|CC/CV charge| n5
  n10 -->|stick inputs| n4

Analysis

The verification audit showed that subsystem and interface requirements were well-covered (all 29 SUB and all 22 IFC requirements had VER entries), but system requirements were nearly uncovered: only {{sys:SYS-REQ-011}} and {{sys:SYS-REQ-012}} had verification entries from earlier sessions. This is a trace-chain gap — each STK need drives a SYS requirement which drives decomposition, but without VER entries on the SYS requirements there is no acceptance criterion at the system boundary.

Cross-domain search surfaced a strong analog between the {{entity:ESC Microcontroller}} ({{hex:D1F53018}}) and the {{entity:Points and Crossing Drive System}} from railway signalling ({{hex:D7F53018}}, 30 shared traits). Both are real-time embedded controllers driving high-current actuators with deterministic timing requirements and safe-state obligations. The railway domain’s pattern of “de-energise to safe” (points default to straight track) mirrors the ESC’s throttle-cut failsafe. This supports the existing safe-state requirement {{sub:SUB-REQ-025}}.

Lint produced 89 findings (5 high, 84 medium). The 5 high-severity findings were all ontological artifacts: three arose from the lint entity parser extracting fragments of requirement text (“kids remote control airplane shall display”, “esc”) as entity names; one reflected the {{trait:Biological/Biomimetic}} trait being set on {{entity:Kids Remote Control Airplane}} due to aerodynamic wing analogy rather than biological material content; one flagged the {{entity:Flight Control Electronics}} mounting interface as lacking a physical housing entity. All four were acknowledged with engineering rationale stored in the SE namespace.

Requirements

Ten system-level verification entries created ({{ifc:VER-REQ-073}} through {{ifc:VER-REQ-082}}), one for each uncovered SYS requirement:

  • {{ifc:VER-REQ-073}}: Flight envelope test — mass weigh plus 60s level flight at 5–15 m/s
  • {{ifc:VER-REQ-074}}: Control latency bench test — logic analyser from stick ADC to servo output, 50 ms pass criterion
  • {{ifc:VER-REQ-075}}: Stability augmentation — rate table injection plus flight trial bank angle limit
  • {{ifc:VER-REQ-076}}: Failsafe timing and descent rate — transmitter power-off, current probe, barometric descent measurement
  • {{ifc:VER-REQ-077}}: Charger termination — cell voltage and surface temperature test to 4.20 V / 45°C limits
  • {{ifc:VER-REQ-078}}: Propeller frangibility — 1N-increment force gauge test to 15N yield
  • {{ifc:VER-REQ-079}}: RF link range — 150 m field test with three co-channel WiFi APs active
  • {{ifc:VER-REQ-080}}: Crash impact — 5m drop onto grass, battery retention and no sharp edge inspection
  • {{ifc:VER-REQ-081}}: Unboxing trial — 5 children aged 10, printed instructions only, 10 min pass criterion
  • {{ifc:VER-REQ-082}}: LVC progressive cutoff — bench supply stepping 3.5V to 3.0V/cell, RPM and audible warning monitored

Each entry carries a verifies trace link back to its parent SYS requirement. SYS verification coverage is now 100% (12/12).

Next

SYS verification coverage is now complete. STK requirements have lower VER coverage (2/14 with entries) — next session should add VER entries for the remaining 12 STK requirements. Additionally, the lint medium-severity findings (84 remaining) should be triaged to distinguish genuine gaps from classification noise before the project advances to validation.

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