CAT II & III requirements

[FlapsOne]

I found that - not convinced I understand what it's saying though. Need to read it a couple more times. Tend to agree with wtcoffee that it should be less not greater but more examination required.

The bit I was referring to that's not convered in Jar Ops is the manual Cat 3 stuff using HGS. Not a mention.

Maybe it's covered by the phrase

"....Other forms of guidance systems or displays may be certificated and approved."

[Dmax]

Maybe it's covered by the phrase

"....Other forms of guidance systems or displays may be certificated and approved."

I think too.

Davide

[Drop The Dunlops]

Originally Posted by Graybeard

The Flight Dynamics (now RockwellCollins) HGS, Headup Guidance System, was initially certified in about 1977 on the 727-200 at Alaska Airlines to CAT IIIa, 50' DH and 700' rvr. That's hand flown, of course. It has since then been expanded to many airlines and airframes, even those with autoland guidance.

Holy Schmoly, I didn't realise they had been around that long!!!

I thought my Company was progressive when it had them fitted to some 737's in 1998!!!

[ICT_SLB]

Originally Posted by Drop The Dunlops

Holy Schmoly, I didn't realise they had been around that long!!!
I thought my Company was progressive when it had them fitted to some 737's in 1998!!!

You're not really that far out. The original 727 cert was, in reality, a one off. After the authorities took a long hard look at everything, it was back to square one for the next cert - I know because I was part of the team that got hit by the "Proof of Concept" 100 landings to certify the CRJ to CAT IIIa.
One of the biggest things was not the actual approach but how to show TCAS advisories & to have all the data that's crept onto the PFD over the years - so-called "ALL Phases" (sorry didn't mean to shout but it looks too like the AII approach mode otherwise). The Manually-flown HUD approaches have to meet the JAA (EASA?) HUD-3XX requirements IIRC.
BTW I don't have JAR AWO with me but I understood CAT IIIa was for DH less than 100 feet but not less than 50. The real limit is the Minimum Break-off Height - 50% above the min altitude at which you just touch the wheels in a go-around - a hairy thing to fly - I was in the back & it was easy thanks to our project pilot, "Latch". You can fly manually to CAT II w/o HUD guidance in both Canada & the US (if the manufacturer has already certified it) but not JAA-land.

[wheresthecoffee]

The reference to ‘auto-coupled to below DH’ in this table (jar ops) means continued use of the automatic flight control system down to a height which is not greater than 80% of the applicable DH.

Would still really appreciate someone explaining that to me clearly.

It seems to my little brain that 'not greater' should really be 'not less'.

[GlueBall]

It has to do with autoland go-around parameters, which means that the autopilot [or the pilot executing a manual go-around] will actually "dip" below the D/H during the maneuver.