Why would you WANT to...

C150J

Well-Known Member
I just saw that some HUD-equipped Delta 737s allow for a hand-flown, engine-out, CAT II approach. If this IS true (this is second-hand information), why would you WANT to fly such an approach without the aid of an A/P?

Just curious,
J.
 
Cause its ptrobably cheaper than redesigning the 737 to have a fail-operational AFS (i.e. one incantation of this level of redundancy is a minimum of three independent autopilots)
 
I can't find the link but there was an article a few months ago from Dick Karl a few months ago that he wrote after he flew the SWA 737 SIM. If I remember correctly he points out the nice features of the HUD.
 
Our Falcon 900EX's can be certified to fly CAT IIIa approaches with our HGS (HUD) and those approaches must be hand-flown. If we only go for CAT II certification then it is a Coupled Approach (PICMA using Auto-pilot)... The HGS (HUD) system has it's own guidance computer and is not coupled to the auto-pilot. It is a much high resolution computer than the standard FMS system.
 
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why would you WANT to fly such an approach without the aid of an A/P?


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I think on a lot of aircraft, we have restrictions on single-engine approaches. On the -88, we're straight hand-flown category I while single-engine and the autopilot has to be off when we intercept the glidepath.

I guess I'd better look that up since I've got recurrent this weekend.
 
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I guess I'd better look that up since I've got recurrent this weekend.

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It would just be your luck if your sim check pilot were reading this too! Hmmm... guess who's about to lose an engine?

wink.gif

Dave
 
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I guess I'd better look that up since I've got recurrent this weekend.

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It would just be your luck if your sim check pilot were reading this too! Hmmm... guess who's about to lose an engine?

wink.gif

Dave

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Ha! I think the first time I spent more than 5 minutes flying the -88 with two engines was during IOE!
smile.gif
 
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Our Falcon 900EX's can be certified to fly CAT IIIa approaches with our HGS (HUD) and those approaches must be hand-flown. If we only go for CAT II certification then it is a Coupled Approach (PICMA using Auto-pilot)... The HGS (HUD) system has it's own guidance computer and is not coupled to the auto-pilot. It is a much high resolution computer than the standard FMS system.

[/ QUOTE ]FC, are you guys seeking Cat II/III certification for your aircraft? I had read some stuff about the process a while back ... apparently there's not an extensive amount of use for it in the USA (especially since the big GA airports don't have Cat II/III approaches anyway!) but that it can make operating overseas a whole lot easier, especially in Europe.
 
At Delta the 737-800 can actually be handflown to Cat-III with one or both engines running.

Why would you want to (engine out)?

First of all the HUD works great. As part of checking out in the airplane when we first got them we went out and shot touch and goes with the flying pilot's outside vision obstructed. Many takeoffs and landings on a relatively windy day and all were right in the touchdown zone and right on center line, every time. This was a great confidence building exercise.

The HUD allows for much lower minimums for takeoff. So the problem arises, what do you do if you lose an engine during a verly low vis takeoff? The answer WAS you HAD to divert to an airport with CAT 1 minimums. Now with approval to shoot CAT-III with an engine out we at least have the option of landing at airport of departure vs. a long divert on one engine.
This also allows greater dispatch flexibility since you don't absolutely require a take-off alternate during low-vis ops. (As always the captain may require more wiggle room than the absolute letter of the law).

Also, the 737 A/P is two axis. So the pilot must make all rudder inputs. And in any handflown CAT-III approach the auto-throttles can't be engaged. And the A/P flare program is not setup for engine out/ flaps 15 etc. etc. Long story short, it only really works to hand fly an engine out approach, whether it's VFR or CAT-III.

Personally, with 4 years experience with the system, I wouldn't hesitate to shoot a hand-flown CAT-III approach engine out or both running.

BTW the HUD equipped 800 can be dispatched to CAT-III minimums with the A/P inop. The HUD really gives us a lot of operational flexibility.

The crazy thing is in four years on the airplane I haven't even shot as low as a CAT-II approach. The one time I thought I might get to shoot a CAT-III the weather was below CAT-III mins and had to divert. On the MD-88 I shot several CAT-II and CAT-III approaches.
 
Probably the standard 737-200's are two-axis, but on the 737-200 adv's I flew, the aircraft would 'de crab' itself during autoland.
 
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FC, are you guys seeking Cat II/III certification for your aircraft? I had read some stuff about the process a while back ... apparently there's not an extensive amount of use for it in the USA (especially since the big GA airports don't have Cat II/III approaches anyway!) but that it can make operating overseas a whole lot easier, especially in Europe.

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We MIGHT go for CAT II certification only, this way we can use the same procedures for both our 900EX's and 50EX's... The reason we would go for CAT II is simply operating in Europe... a LOT of our travel is International and this would make a difference for us...
 
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Probably the standard 737-200's are two-axis, but on the 737-200 adv's I flew, the aircraft would 'de crab' itself during autoland.

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Really? The 800 has no rudder input from A/P so filot flying de-crabs the airplane. I can't honestly remember whether 200s were that way. (Too many decades ago). Are you taling about the Delta 200s Doug?

Dave
 
I dunno, I can't find a reference, but perhaps MDPilot remembers.
 
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