{
  "slug": "flying-height",
  "term": "Flying height",
  "aliases": [
    "fly height",
    "head-disk clearance"
  ],
  "definition": "Flying height is the physical clearance between a flying HDD head/slider region and the disk surface.",
  "note": "Specify the measurement location: clearance near the read/write element need not equal clearance elsewhere on the slider. Smaller recording spacing and avoidance of unintended contact impose competing constraints [control]. This is a length, not a SMART event count; no universal present-day nanometer value is assigned here.",
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "related": [
    "hdd",
    "head-disk-interface",
    "thermal-flying-height-control",
    "head-slap"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "control",
      "title": "Juang and Bogy: Design and Analysis of a Flying Height Control Slider with Thermal Nanoactuator, CML report 06004, sections 1-2",
      "url": "https://cml.berkeley.edu/wp-content/uploads/blue-reports/06004.pdf",
      "accessed": "2026-10-15"
    },
    {
      "id": "analysis",
      "title": "Hesela: HDD mechanical faults, evidence and diagnostic limits",
      "url": "https://hesela.com/analyses/hdd-mechanical-failure-points/",
      "accessed": "2026-10-15"
    }
  ],
  "updated": "2026-10-15"
}