System

{{entity:Kids Remote Control Airplane}} — QC session 491 on the Kids RC Airplane project (se-kids-remote-control-airplane). Entering this session: 127 requirements across 6 documents, DECOMP_STATUS qc-reviewed, but REVIEW_NOTES flagging a VER coverage gap: 48/95 SUB reqs and 9/42 IFC reqs without verification entries. After several decomposition sessions since that review, the project stood at 29 SUB + 22 IFC = 51 total requirements in those documents, with only 22 carrying verifies trace links. This QC session focused on closing the VER gap completely.

Findings

Verification coverage: 22/51 SUB+IFC requirements (43%) had verifies trace links going into this session. The 29 uncovered requirements included safety-critical items: {{sub:SUB-REQ-013}} (LVC cutoff within 200 ms), {{sub:SUB-REQ-018}} (receiver failsafe within 500 ms), {{sub:SUB-REQ-022}} (battery ejection under 10 m/s crash impact), and {{sub:SUB-REQ-015}} (charger termination at 4.20 V per cell). None of these had test procedures or trace links to verification entries.

IFC coverage was worse — 16/22 IFC requirements (73%) had no VER entries. This included {{ifc:IFC-REQ-003}} (RF compliance), {{ifc:IFC-REQ-014}} (XT30 polarity keying), {{ifc:IFC-REQ-016}} (vibration isolation for FCE PCB), and {{ifc:IFC-REQ-017}} (transmitter joystick ergonomics for child hand size).

Orphan trace links: VER-REQ-036 and VER-REQ-037 (user trial procedures verifying {{stk:STK-REQ-001}} and {{stk:STK-REQ-002}}) were orphaned — no STK→VER linkset exists in this project. Linked via {{sys:SYS-REQ-009}} and {{sys:SYS-REQ-003}} respectively using the SYS→VER linkset.

ARC orphans: 7 architecture decision records (ARC-REQ-001 to ARC-REQ-007) remain orphaned because no ARC linkset exists. Tagged as informational — these are design rationale entries, not traceable requirements.

Lint: 89 findings (5 high, 84 medium). The high-severity findings flag an ontological mismatch: {{entity:kids remote control airplane}} is classified {{hex:DEC81008}} with Biological/Biomimetic trait (bit 3) — a corpus artefact from wing/aerodynamic surface analogy. Addressing this reclassification is out of scope for this QC pass.

Corrections

Created 29 VER requirements ({{sub:VER-REQ-044}} through VER-REQ-072) and 29 verifies trace links to close the SUB+IFC gap. Prioritisation was by safety criticality:

• Safety-critical (SIL-2) SUB procedures: LVC timing bench test ({{sub:SUB-REQ-013}}), receiver failsafe response measurement ({{sub:SUB-REQ-018}}), crash battery retention drop test ({{sub:SUB-REQ-022}}), overcharge termination accuracy ({{sub:SUB-REQ-015}}), failsafe bind configuration ({{sub:SUB-REQ-009}}).
• Performance SUB procedures: thrust measurement on load-cell stand ({{sub:SUB-REQ-002}}), thermal test at 75% throttle ({{sub:SUB-REQ-006}}), 8-minute flight-time endurance ({{sub:SUB-REQ-010}}), stability augmentation 3-axis stand test ({{sub:SUB-REQ-019}}).
• IFC procedures included RF compliance inspection ({{ifc:IFC-REQ-003}}), XT30 polarity keying inspection ({{ifc:IFC-REQ-014}}), VNA antenna VSWR sweep ({{ifc:IFC-REQ-010}}), FCE vibration isolation drop test ({{ifc:IFC-REQ-016}}), and child ergonomics joystick evaluation ({{ifc:IFC-REQ-017}}).

Total project state after corrections: 156 requirements, 72 VER entries. SUB+IFC coverage: 51/51 (100%).

Decomposition

flowchart TB
  n0["Kids Remote Control Airplane"]
  n1["Airframe Subsystem"]
  n2["Propulsion Subsystem"]
  n3["Flight Control Electronics"]
  n4["Radio Transmitter"]
  n5["Power System"]
  n6["Ground Charging System"]
  n7["USB Power Supply"]
  n8["Atmosphere"]
  n9["2.4 GHz ISM Band"]
  n10(["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

Residual

ARC orphans (7): No ARC linkset in this project schema; tagged informational. These remain structurally orphaned but are distinguishable from traceable requirements by tag.

Lint findings (89): The Biological/Biomimetic mismatch on {{entity:kids remote control airplane}} {{hex:DEC81008}} generates 20+ medium findings. This is a Substrate reclassification task, not a requirements fix — requires uht-substrate entities reclassify with corrected context. Deferred.

Coverage gap items flagged by lint (SYS-to-SUB concept gaps, findings 82-89): concepts like “control surface response”, “receiver”, “propeller”, and “2.4 GHz FHSS control link” appear in SYS requirements but lint reports no corresponding SUB requirements. These likely exist but under different wording — a semantic match limitation, not a genuine gap. Deferred to validation session.

Next

VER coverage is now 51/51 for SUB+IFC. The project can advance to validation (SE_VALIDATION) which should audit the SYS→VER chain end-to-end, verify the SIL-2 safety argument for hazards H-001 (signal loss/runaway) and H-002 (LiPo thermal event), and walk the STK→SYS→SUB→VER trace for each ConOps scenario.