What is the distance from an airport from which an airliner climbs above 550 m?

Question

Is it possible to determine a common distance from the runway threshold at which an airliner climbs above 300 metres and 550 metres above-ground-level (AGL)?

And for landings? Where do they descend below it?

I need to determine at least an approximate value of common distance. But in the best case I’d like to determine:

• the maximum distance
• the minimum distance
• the average distance or the distance which is used by most airliners.

I am not from aviation, thus I need to ask this question to professional pilots. The aim is related with the “Bird strike problem”. 300 m and 550 m – is respectively the common height and the maximum height of flight of Black vulture - a bird species living in South and North Americas which caused the most strikes with aviation within its range. I’m doing the scientific research and study the risk of collision with this bird and the possible measures to decrease this risk.

Answer 1

For the landing is quite easy.

Airliners usually approach an airport descending along $3^\circ$ slopes. This means that they will be 300m AGL approximately 5.7km before the runway threshold, and they will be at 550m AGL about 10.5km before the same point.

For the take-off the situation is a bit more complicated, as each aircraft will have a different performance. Taking a value of about 1000ft/min for the vertical velocity and 200Kts for the forward velocity (in aviation we use the imperial system, for a bit of background see here) we get similar distances to the above (it is a $2.8^\circ$ slope)

Note that these paths are more or less a straight continuation of the runway, particularly on the landing side (less so on the take off side).

Each airport has approach and departure procedures, you could try to have a look at those. They are usually published by Jeppesen.

Answer 2

There are no pre-set figure for this, as it depends on the airport and surrounding geography, aircraft performance, departure and approach procedures. ATC instructions, etc.

For departures, airports don't publish a standard point where you must reach these altitudes but they sometime publish Obstacle Departure Procedures (ODP) which will specify a minimum climb gradient which the performance capabilities of your aircraft must be able to achieve in order to safely fly the ODP. This gradient is usually listed in hundreds of feet per nautical mile. ODPs assume that you, the pilot will be able to achieve an initial climb of 500 FPNM and an altitude of at least 35 ft above field elevation by the time you clear the departure end of the runway, climb straight ahead to an altitude of at least 400 ft AFE prior to beginning your first turns from runway heading, thence maintain a climb gradient at or above the minimum listed to the waypoint listed on the ODP.

An example is as follows: Glenview Airport (KABC) has a RIVER1 ODP, which requires your aircraft to depart runway 27 thence

"climbing right turn to a heading 307° to intercept the 287° radial from the ABC vortac to CYRAC intersection 16 DME from ABC at or above 4500 feet, thence resume own navigation. Minimum climb gradient of 450 feet per NM to CYRAC."

If you are flying a C-172 and assuming a Vy of 76 KIAS, you must achieve a rate of climb of (450*76)/60 = 570 feet per min from the departure end of runway to CYRAC intersection in order to safely fly this departure procedure.

Descent and landing will usually involve the use of feeder routes from established Juliet (Jet) airways onto Standard Terminal Arrival Routes (STARs) which have established step down fixes at specific waypoints along the STAR or as advised by ATC. The STARs then feed into the specific instrument approaches for the destination airport which also has step down fixes prior to final approach fix which descends from there to either a missed approach point (non-precision app) or a decision altitude (precision app). A pilot must have confirmed visual acquisition of the runway environment from that point and the weather at the airport must be at or above the published minimums in order to continue to approach and land, else the pilot must go missed and fly the missed approach procedures for that plate.