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ILS in an ATR

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ILS in an ATR

Old 8th Jan 2019, 14:30
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ILS in an ATR

I retired from flying some twenty years ago so am very out of date about modern capabilities. I flew S61 and civilian Chinook helicopters with Cat 1 ILS experience

I recently flew with Aer Lingus from Newquay to Dublin in an ATR, I think, the 600 version. Driving into Newquay I had expected delays or even cancellations due to the weather. I estimated a visibility of 150-200 metres and the cloud close the surface.

However the flight info said the inbound flight was on time and it was. It arrived, turned around and we departed on time.

My questions, does the ATR have IRS, would it be equipped for Cat 3 ILS and how standard are Cat 3 operations today?
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Old 8th Jan 2019, 15:15
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Originally Posted by Boslandew View Post
I retired from flying some twenty years ago so am very out of date about modern capabilities. I flew S61 and civilian Chinook helicopters with Cat 1 ILS experience

I recently flew with Aer Lingus from Newquay to Dublin in an ATR, I think, the 600 version. Driving into Newquay I had expected delays or even cancellations due to the weather. I estimated a visibility of 150-200 metres and the cloud close the surface.

However the flight info said the inbound flight was on time and it was. It arrived, turned around and we departed on time.

My questions, does the ATR have IRS, would it be equipped for Cat 3 ILS and how standard are Cat 3 operations today?
Yes, some ATR are equipped with one IRS, which is required for RNP AR operations.
Air New Zealand was the leading customer for this type of operations.

However, AFAIK ATR are only certified for ILS CAT 2 operations.
Also, some models are not equipped with an IRS.

Currently, ATR is trying to implement EVS and SVS.
On this page you'll see the (former) ATR protoype and a test pilot with the head mounted display from Elbit :
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Old 8th Jan 2019, 15:16
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According to wikipedia the 600 series has CATIII capability: https://en.wikipedia.org/wiki/ATR_42#ATR_42–600

From some googling a video you might like, it is CAT II but still very impressive.

Quite a few airports would need to shut down several days per year without CATIII.
Regional airliners in the US are often only equipped CATI or CATII but seems like Dublin and destinations are foggy enough for Aer Lingus to equip CATIII. (Or maybe it was just CATII hard to know)

Most A320/B737 and bigger aircraft are usually CATIII capable or it is at least a customer option. Not all but most operators qualify their crews to perform CATIII.
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Old 8th Jan 2019, 20:30
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Stobart ATRs aren't equipped with IRS and are only approved down to CAT II minima. The ATR CAT III certification has stalled due to a lack of Autothrottle/thrust (whatever you call it on a power lever aircraft) last I heard. So if that was the runway RVRs your quoting at the time of landing.....not sure.
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Old 8th Jan 2019, 20:57
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The Dash 8's can actually do Cat IIIA down to 200m RVR and 50ft DH using Head-Up-Guidance which requires an extra IRS to be installed. They don't have autothrottles either and the 400s have extremely sensitive power levers which I imagine to be quite tricky to handle on an ILS. AFAIK the HGS system establishes a path in space using the ILS and then blends out the ILS signal on the last few feet to avoid any beam distortions close to the ground. It gives guidance down to the flare. (Same for the Canadair Jets and as an alternative to Autoland on the Embraer 170/190 series).

Are autothrottles actually required to be operative for autoland on other types? It wasn't on the Fokker 70/100.
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Old 8th Jan 2019, 22:18
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Alpine Flyer

I Can only reference the 737, for which as far as I recall a cat 3A autoland can be flown with the auto-throttle inoperative, or at least you can continue and land if the auto-throttle fails, I can't remember if you can commence the approach with it inoperative, but I think you can.

On the 737 with HGS both auto-pilot and auto-throttle are disengaged at or above 1000 ft above the airfield for cat 2 or 3A, and the approach is flown entirely manually. Whether that is sensible at the end of a long night is questionable, but that is the procedure.

As for the Q400, the SOP has obviously changed since I flew it as the Captain used to fly the approach and landing, or maybe the F/O flying is a flybe thing. Most of the time for cat 2 conditions the atmosphere is fairly stable, I don't remember any issues with thrust lever response, and I flew a fair few actual cat 2 approaches in it, and taught them in the simulator.
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Old 8th Jan 2019, 23:27
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Auto thrust is required in the A320 for any Cat3 ops. Only down to Cat2
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Old 9th Jan 2019, 03:58
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The 737 with HUD can do manually flow / manual thrust Cat IIIa in AIII mode.
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Old 22nd Jan 2019, 11:54
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ATR Newquay

Gentlemen

Many thanks for your replies. My estimate of visibility was made initially from the carpark and then during the very short walk to the aircraft. From your replies, it would appear most likely to have been a Cat II approach and departure.
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Old 22nd Jan 2019, 22:21
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On the 737 Classic the autothrottle was not relevant to autoland or LVP at all. Apart from the HGS explanation above, is the NG any different?
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