Sierra Pattern A320 Page

| Feature | Sierra Pattern (A320) | Conventional (e.g., Boeing 737) | | :--- | :--- | :--- | | Initial lateral mode | GA TRK (holds existing track) | TO/GA (wings level or runway heading) | | Initial vertical mode | SRS (maintains V2) | Pitch hold or MCP selected | | Pilot workload | Low (monitoring) | Higher (immediate pitch/thrust setting) | | Obstacle protection | Automatic (via FMGC) | Pilot-managed |

The most famous unpowered glider event was Air Canada Flight 143 (the Gimli Glider), a Boeing 767. The 767 has a superior glide ratio (12:1) and manual reversion (cable controls). The A320 has no manual reversion. Lose all hydraulics (impossible unless RAT fails), and you lose control. sierra pattern a320

The A320's closest near-miss occurred in 1994 over Afghanistan. A Ariana Afghan Airlines A320 ran a tank dry, then the crossfeed failed. The crew descended from FL 330, and the captain manually pumped the fuel by cycling the boost pumps—an ad-hoc Sierra Pattern. They restarted at 12,000 feet. | Feature | Sierra Pattern (A320) | Conventional (e

The "Sierra" designation also finds its way into the aircraft's navigation logic. In the A320’s Flight Management Guidance Computer (FMGC), specific procedure turns are often defined by patterns. A "Standard Instrument Departure" (SID) might require a specific set of twists and turns—a geometric dance designed to thread the needle through noise-sensitive areas or terrain. Lose all hydraulics (impossible unless RAT fails), and

While there isn't a single maneuver officially called "The Sierra Turn," pilots often use "S" turns to bleed off speed or align with the runway, painting a serpentine pattern in the sky that traces the silhouette of the letter itself.