5 Challenges ASAP STAR Enroute Driftdown Helps Resolve
From terrain and obstacle clearance to flight-planning integration and diversion-airport analysis, discover how ASAP STAR supports aircraft-specific engine-out performance planning.
When evaluating aircraft performance, takeoff and landing calculations often receive the most attention. But what happens if an aircraft experiences an engine failure at cruise altitude?
An engine failure can significantly reduce an aircraft's ability to maintain altitude, particularly when operating over mountainous terrain or along routes with challenging obstacle-clearance requirements.
Aircraft weight, atmospheric conditions, terrain elevation, planned routing, and available diversion options all become important considerations.
For flight operations departments, understanding these limitations before departure is essential to effective contingency planning.
ASAP STAR Enroute Driftdown provides aircraft-specific Method 1 and Method 2 analysis, terrain and obstacle evaluations, flight-planning integration, and advanced diversion-airport capabilities to support informed operational decisions.
See ASAP STAR Enroute Driftdown in Action
1. Understanding Aircraft Engine-Out Performance Limitations
When an engine fails during cruise, an aircraft may no longer be capable of maintaining its planned altitude. Its performance depends on several factors, including aircraft weight, atmospheric conditions, and the applicable single-engine performance characteristics.
How ASAP STAR helps:
STAR supports aircraft-specific Method 1 and Method 2 driftdown calculations, allowing operators to evaluate applicable engine-out performance limitations. The analysis incorporates relevant performance data to help determine aircraft capabilities under the planned operating conditions. STAR also supports single-engine service ceiling considerations and engine-out performance assessments throughout the route.
Operational benefit: Greater visibility into aircraft-specific engine-out limitations before departure.
2. Maintaining Required Terrain and Obstacle Clearance
An aircraft's engine-out descent capability becomes especially important when operating over mountainous terrain or other challenging environments. An engine failure may require a descent from cruise altitude, making terrain and obstacle clearance critical considerations along the planned route.
How ASAP STAR helps:
STAR evaluates aircraft driftdown performance against applicable terrain and obstacle-clearance requirements.
Depending on the analysis method and operating conditions, operators can assess:
Engine-out altitude capability.
Applicable terrain and obstacle-clearance requirements.
Performance limitations along the planned route.
Aircraft-specific atmospheric and weight considerations.
These calculations help identify where engine-out performance may restrict the operation.
Operational benefit: Better-informed route planning with visibility into terrain and obstacle limitations.
3. Accounting for Changing Aircraft Weight and Fuel Burn
Aircraft weight has a direct influence on engine-out performance. As fuel is consumed during flight, aircraft weight decreases, potentially changing its driftdown capabilities.
Evaluating engine-out performance without considering these changes may provide an incomplete picture of the operation.
How ASAP STAR helps:
STAR incorporates relevant aircraft weight and fuel burn information into driftdown analysis. This allows operators to evaluate performance with consideration for expected weight changes along the route, rather than relying solely on one fixed aircraft weight.
Operational benefit: A more comprehensive assessment of engine-out performance throughout the flight.
4. Eliminating Disconnected Flight-Planning Workflows
Flight-planning systems already contain valuable operational information, including the planned route, waypoints, altitudes, and fuel data. When this information must be manually entered again into a separate driftdown application, it creates unnecessary workload and additional opportunities for input errors.
How ASAP STAR helps:
STAR can integrate directly with compatible flight-planning systems, automatically receiving relevant information for engine-out performance analysis.
Depending on the integration, this can include:
Planned flight routes.
Route waypoints.
Planned altitudes.
Relevant aircraft weight and fuel information.
This helps connect the operational flight plan with STAR's aircraft-specific driftdown calculations.
Operational benefit: Reduced duplicate data entry, streamlined analysis, and improved consistency between flight planning and performance calculations.
5. Evaluating Diversion Airports, Routing, and Weight Penalties
Understanding an aircraft's engine-out capability is only part of contingency planning.
Operators also need to consider what alternatives may be available if an engine failure occurs along the route. Which airports are applicable for diversion? What routing would be required to reach them? Are there additional aircraft performance limitations that affect those options?
How ASAP STAR helps:
STAR's Method 2 Driftdown Analysis includes the ability to identify applicable diversion airports and evaluate individual diversion options.
For each applicable airport, STAR can incorporate:
Diversion airport identification: Generate a list of applicable airport options.
Diversion routing: Apply the associated route for each airport.
Route waypoints: Include applicable waypoint information for diversion analysis.
Aircraft weight penalties: Calculate the associated weight penalty for each diversion option.
Performance considerations: Evaluate relevant engine-out limitations to support contingency planning.
This functionality provides operators with a more complete picture of potential diversion alternatives and their associated performance implications.
Rather than evaluating engine-out descent capability in isolation, operators can assess how available airport options and their routing affect the aircraft's performance requirements.
Operational benefit: More informed diversion planning and greater visibility into the weight and routing limitations associated with different options.
From Flight Planning to Engine-Out Contingency Analysis
ASAP STAR Enroute Driftdown goes beyond basic single-engine performance calculations. By connecting aircraft-specific performance, terrain and obstacle analysis, changing aircraft weight, flight-planning data, and Method 2 diversion-airport evaluations, STAR helps operators understand the operational limitations that matter throughout the route.
For airlines and flight departments managing complex routes, these capabilities can help streamline preparation and provide valuable information for engine-out contingency planning. With connected Web and iPad workflows, STAR supports coordination between dispatchers and flight crews.
Beyond the Runway. Throughout the Route.
ASAP STAR Enroute Driftdown brings engine-out performance analysis, terrain clearance, flight-planning integration, and diversion-airport evaluations together within one connected platform. Backed by more than 30 years of aircraft performance expertise, ASAP develops solutions designed to help operators fly safer, smarter, and more efficiently.
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