Avia Solutions — Aviation Technology Solutions

Service · Engine Out Procedures

Engine-out departures, proven against the AFM.

Net take-off flight path analysis to FAR 25.115, generated from your own aircraft's certified AFM charts — for the departures where terrain, not thrust, is what limits you.

Discuss a departure

The problem

An obstacle-critical departure is not a table lookup.

When an engine fails after V1 out of an airport ringed by terrain, what clears the ridge is a specific net flight path at a specific flap setting, weight and temperature — flown along a specific track. Producing that path correctly means reading the manufacturer's own charts, not approximating them, and applying the regulation the way the certification basis actually applies it.

Where most analyses quietly go wrong. The third segment is commonly modelled with an assumed acceleration height and distance. Those placeholders decide whether you clear the obstacle. We removed them: the level-off height and the second- and third-segment end distances are read from the AFM's own curves, for each flap setting, and the engine uses those.

What we deliver

The path, the verdict and the working.

01

The net take-off flight path

Segment by segment — first and second to level-off, the third at the five-minute limit, the fourth at the AFM's net en-route gradient — for the flap setting and the weight and temperature of the case.

02

Obstacle clearance along the track

The path flown against the actual departure track, including the turn, and checked against the terrain and obstacles that track passes over. Gross and net paths both reported.

03

The reasoning, in writing

Every input traced to the AFM figure it came from — reference gradient, level-off height, segment distances, flap retraction speed. Work that has to survive a regulator reading it.

Method

FAR 25.115, applied where it actually bites.

The 0.8 % net penalty in the third segment is not a reduction in height. Under FAR 25.115 it is applied as an equivalent reduction in acceleration — so the third segment gets longer, and the gap between gross and net stays constant across it. Getting that backwards makes an analysis look conservative while it is not.

  • Reference gradient interpolated from the AFM figure for the case weight and temperature.
  • Level-off height read from the reference-gradient scale of the flight-path figure, per flap setting — not assumed.
  • Second- and third-segment end distances read from the AFM curves at zero wind, then corrected to ground distance for the reported headwind.
  • Climb flattening with altitude accounted for: thinner air means less thrust, so the level-off sits further out than a constant-gradient projection suggests. We model the climb to level-off conservatively rather than optimistically.
  • Fourth segment at the AFM's net en-route gradient for the level-off altitude.
Screenshotimg/shot-engineout-profile.jpg
net take-off flight path profile

Source data

Your AFM, digitised chart by chart.

The performance figures come out of your aircraft's Airplane Flight Manual using Graphite, our own AFM curve digitiser — each chart captured with its axes, its units and its reading tolerance recorded, so the numbers in the analysis can be traced back to the page they came from.

  • Reference gradient, flight path, gear-up and net en-route figures captured per flap setting.
  • Turn-loss data taken from the AFM's published table where the manufacturer publishes one.
  • Digitised sets are kept and reused — the second departure at the same type costs a fraction of the first.
Screenshotimg/shot-engineout-charts.jpg
digitised AFM figure in Graphite

Validation & coverage

Checked against the manual's own worked example.

Before an aircraft's data goes into service, the engine has to reproduce the example the AFM itself publishes — reference gradient, level-off height, third-segment end distance, fourth-segment net gradient and flap retraction speed, all inside chart reading tolerance. If it cannot, the digitisation is wrong and we go back to the charts.

Send us the departure that worries you.

An airport, a runway, an aircraft type and the weights you dispatch at. We will tell you what it takes to analyse it properly — and whether your current numbers hold.

Discuss a departure