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Embraer E170/190/175/195 v3 Steep Approach


LecLightning56

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9 hours ago, Matty260191 said:

No sorry i was wrong but it will stay at vapp with full flaps 

I might be interested in the product if you feel it can stay at Vapp on e.g. an ILS approach to London City (approximately 5 degrees glideslope?), and not deviating above or below the glideslope path. What is your experience?

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Not tried yet but other I spoke too have and it worked out. The EGLC ILS would be a manual job anyway and the come in on VREF for a steep app as it helps the sink without speed gain so much(told by a real pilot). I will get round to trying it you could do it in the old version so i suspect if a fully dirty config it will work. But like I said don't expect autopilot to be able to perform miracle and a 5.5 degree GS is best flown by hand. I would leave the AT managing speed first as I suspect it will be more stable that me at keeping the speed right while i concentrate on flying. If it wont do it the it may have to be manual throttles too. I believe like boeings the A/T is designed to be left on and idle itself on flare.

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  • 2 weeks later...
  • 3 weeks later...

I have done a little experimentation with the steep approach to London City. Clearly the real world aircraft has a ventral speedbrake to facilitate the steep approach which we cannot obviously simulate. So, what I have done is I have modified the aerodynamic coefficients for maximum flap deployment in the .air file for e.g. the 170 to account for the effect of a speedbrake in this configuration. If you initiate a 8nm final to London City at a VAPP of approximately 120 knots, the glideslope is captured by the aircraft with initially speed increasing by a few knots, then speed reducing to VAPP once the glideslope is stabilised correctly (the aircraft is initially high and lags a little in manoeuvring to establish on the glideslope which results in initially a steeper approach path and hence increasing speed: this is corrected later with the speed reducing back to VAPP).

I cannot recommend that anyone fiddles with the .air file for these aircraft, but what I have done only applies to full flap deployment. The use of full flap is presumably more advantageous for the London City approach to achieve the slowest speeds for the shorter runway. The changes to the aerodynamic coefficients do not apply to other flap settings e.g. flaps 5 if the definitions of CL, CD and Cm in the .air file are correct.  If anyone is interested in what changes I have made then please PM me.

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  • 2 months later...

Guys,

With the recent release of the SP1 update I have revisited the steep approach scenario again (London City EGLC) and have made some interesting discoveries.

First and foremost, the A/T maintains constant speed throughout the steep descent once having captured the localizer and glideslope with the SP1 release, whereas previously the speed increased quite dramatically. I do appreciate of course that the FeelThere EJets are not strictly steep-approach compliant on account of an inability to deploy the speedbrakes for such approaches, as is the case for real-world aircraft which have gained such certification. 

Secondly, as an experiment I happened to note that the response of the FeelThere aircraft to capturing the glideslope was slightly sluggish and the aircraft would remain slightly high on the glideslope initially (i.e. above the prescribed flightpath for the approach) and with a consequent higher vertical speed than should be the case if following the glideslope correctly. I then decided to experiment with the Touch Control Steering (TCS) with interesting results. If you arm the localizer and glideslope and wait until the glideslope diamond indicator has dropped to just one notch above its centered position for the correct glideslope then immediately use TCS to drop the aircraft gradually (but not too abruptly) to a flightpath angle of about 4 to 5 degrees pitch down (with autopilot still on), there reaches a point where the glideslope is captured completely and no further TCS inputs have any effect. If you then release the TCS button on your yoke or joystick, the aircraft follows the glideslope exceptionally well. Whereas I am sure that this may not be a correct procedure for glideslope capture in the real-world for very good safety reasons (correct me if I am wrong), but the use of TCS with the FeelThere EJets does seem to be beneficial in maintaining the correct glideslope on a steep approach. For London City there is no certification for autoland, but the approach can be flown safely if you fly to the minimum decision altitude before manually landing the aircraft and with the autothrottle selected throughout by the means described.

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27 minutes ago, LecLightning56 said:

I then decided to experiment with the Touch Control Steering (TCS) with interesting results.

Very interesting. You're doing a great job with your experimentation. Have you tried TCS in other situations? It's something that is rarely commented on. With the v2 Ejets I found it to be a bit hit and miss in use. I'm collecting as much info as I can about version 3, so I can decide if it's worth updating my cockpit,  which is a major operation, and the eye candy is irrelevant.

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