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As a passenger on a commercial flight into Essaouira From London Luton a short while ago, I noticed the aircraft made several quite steep banked turns, all to left, very close to landing. When I say close I mean about five minutes before we touched the runway, and I'd estimate 600-1500 feet off the ground at most. It was possible to make out individual bushes in detail in the scrub. What was more concerning was that the terrain became undulating and was rising into rounded hills with a height difference of around 250 feet.

Sky was clear, and I don't remember any turbulence near the airport.

Is it normal to bank that close to the ground? I thought an approach was lined up further out and higher up.

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    $\begingroup$ Essentially all turns in an aircraft are banked, so your question is just "Why did the aircraft turn before landing?" and the answer is "So it was pointing at the runway." $\endgroup$ – David Richerby May 20 '16 at 0:59
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    $\begingroup$ @DavidRicherby I think more realistically it was "Why did the aircraft make such turns so low and so late?" $\endgroup$ – Carey Gregory May 20 '16 at 1:03
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    $\begingroup$ This landing from the South includes reversing course by 180° at about 5 km from the threshold with two 90° left turns. Does that match your observations? Indeed you are close to the Atlas mountains. At 5 km, with a 5% slope, you are 250 m / 800 ft above the ground. $\endgroup$ – mins May 20 '16 at 5:49
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    $\begingroup$ I highly doubt that the airplane was 600-1500 5 minutes before landing. $\endgroup$ – GdD May 20 '16 at 11:09
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    $\begingroup$ I agree with @GdD. 5 minutes and 600-1500 ft AGL don't go together. The descent rate in approach is normally somewhere in range 600-800 ft/min, so either it was 5 minutes, but then more like 3000-4000 ft, or it was 600-1500 ft, but then it was only 1-2 min. The later would be unusual, but the former would be quite normal point for turning to runway heading. $\endgroup$ – Jan Hudec May 20 '16 at 18:52
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As denizhanedeer said, it was a circling approach. There is only one charted IFR approach to ESU. It comes in from the northwest and would line up for a straight-in approach to runway 16.

ESU approach plate

Depending on the wind the pilot may have needed runway 34 (same runway from the opposite end) so they would circle around to line up with it.

This flight did just that. (It might even be your actual flight, Easyjet 2039 on 5/17/2016) It did a short hold at the final approach fix to lose altitude then circled to land on runway 34. It landed at 4:09 UTC. It did the first left turn at 4:06 and 1850 ft. The image here shows it during the second turn at 4:07 and 1475 feet.

U22039 5/17/2016

The altitudes given are MSL. The terrain rises pretty quickly there. I'm guesstimating from some topo maps that at the area of the turns it rises to 175-200 feet. So 1475 ft MSL would be as low as 1275 ft above ground level.

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  • $\begingroup$ Thanks for your detailed answer. That wasn't my particular flight but an approach to runway 34 seems to match my observations. My flight was 30th APR-16 EZY2039. $\endgroup$ – vanmem May 23 '16 at 16:12
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Now, I'm not an ATP, but as a pilot I know that sometimes I (and commercial airlines) will make "S" turns on final for spacing. There are minimum times between an aircraft taking off/landing and another aircraft landing behind them due to wake turbulence. Instead of making the aircraft go-around (which would take quite a bit of time), they may be asked to slow down as much as safely possible and make the s-turns for spacing.

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  • $\begingroup$ making S turns with airliner is not even a subject. Especially in Luton. $\endgroup$ – denizhanedeer May 20 '16 at 18:37
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    $\begingroup$ @denizhanedeer He was departing from Luton, not landing there. But, yes, airliners do sometimes make s-turns for separation if the aircraft landing in front of them is being slow about clearing the runway. Here's an example of a 747 making s-turns for that reason. That said, it doesn't sound like the turns in the OP's question were s-turns to me. Sounds more like they were just flying the approach (and the OP's estimate of height was probably off.) $\endgroup$ – reirab May 20 '16 at 20:09
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Given that the sky was clear and there are no charted visual approaches in the Moroccan Aeronautical Information Publication for Essaouira (GMMI) -- what I suspect happened was that ATC gave your flight a vector or vectors to a visual final approach after having them descend to the area Minimum Vectoring Altitude. (The Minimum Vectoring Altitude for an area can be lower than the published procedure altitudes.)

Also: while "normal" approaches line up early, airspace or terrain constraints mean there are procedures that call for turns much lower and later than the vectoring your flight receieved. Examples include the main instrument approaches to runway 19 at Reagan National (KDCA).

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    $\begingroup$ From some quick Google Earth measurements, there is some terrain to the south of GMMI that would likely call for some vectoring if landing to the north. $\endgroup$ – Zach Lipton May 20 '16 at 1:38
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I don't know the type of aircraft but most probably you were not so close to ground. In normal stabilised approach it would be approximately 1:30 minutes from 1500 ft to ground. In old days we were making timing approaches for defined ground speeds.

So Second part : Airliners don't make step turns unless otherwise there is emergency. Bank limit for turn 33 degrees for airbus and after that you need to push even more to 67 degrees without slip control. If you make a step turn so close to ground you need to apply a lot of thrust due to load factor to achieve level flight. Also you definitely feel the turn due to increased G.

My option, you may have seen a nice circle to land operation, wind condition may not be the best option for approach runway, either pilot or ATC may ask to circle another runway which is close to ground, but again in safe altitude. 500 ft above the ground an airliner must be aligned and stabilised, unless safety issues.

Above requirements are for conducting a safe flight, depends on carrier and pilot they may have push limits more if you think that you were closer than 500 ft.

Especially in Africa, there are many non-precision approaches and you may need to make approach to one runway and circle to land another one.

I could not find official charts of ESU. Never been there but hope it helps.

Cheers,

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