Greetings

 

I read this  somewhere but can no longer find it. 

 

Can someone confirm the maximum descent rate (to be in compliance with regulations) for the B737-800 during a non-precision approach and a precision approach?

 

From memory it is no greater than 1000- fpm for a precision approach and 1300 feet for non-precision approach.

 

Thank you,  WilloW

 

First time I hear about such rates. Maybe company specific.

 

FCTM says that rates over 1000fpm should be avoided and if approach requires higher rate of descent special briefing should be conducted.

Funny you mention this i was reading the FCOM last night and it mentions V/S set at 1000 fpm on a NPA!

 

 

At descent point:

 

V/S thumbwheel .................................... Select desired vertical speed Select approximately 1,000 fpm descent.

 

Verify V/S engaged mode annunciates.

Ahh of course - the FCOM.....   That's where I read it!    I've been reading so much lately that the sources blend.

 

Thanks,   WilloW

Just to clarify:

There is no regulatory requirement (FAA-land) for min/max rates of descent for precision/non-precision.  The only requirements are to remain above the crossing altitudes and/or the glideslope, as appropriate.

 

The FAA also notes that it is acceptable on an NPA to use either a step-down technique (where the FCOM-suggested 1000fpm would be relevant), or you could work it out mathematically such that you descend at a rate that crosses each point at the required altitude without leveling off.

Thank you Scandinavian13 - very helpful   WilloW

Welcome!

Another tip on NPA always arrive at your MDA before your Mapt!

Normally, the only time you would not use VNAV is if there is an ILS with the G/S out of service and the LOC approach is not selectable in the FMC.

 

So...

 

ILS = approach mode.

ILS, G/S out of service and no LOC approach in the FMC = V/S

Everything else = VNAV.

Spin i got this from ryanair FCOM with a loc app!

 

Like you said above only use V/S not vnav.

 

 

Localizer Approach < RYR >

Complete normal approach preparations. The pitch mode will be V/S.

The roll mode may be VOR LOC or LNAV.

When on an intercept heading to the localizer course:

VOR LOC or LNAV switch ........................................................ Push

Verify LNAV or VOR LOC ARM mode annunciates.

A/P automatically captures the approach course.

Verify VOR LOC engaged mode annunciates upon localizer capture when using VOR LOC.

Canadian Charts also include this handy dandy little box on NPA approach plates:

Hi patrick if you fly the 737 ngx you don't need to use timing

 

Timing During Approaches

 

Since FMC use is appropriate for instrument approach navigation, timing is not the primary means to determine the missed approach point. The probability of multiple failures that would result in timing being the only method of determining the missed approach point is remote. However, some regulatory agencies may still require the use of timing for approaches. The timing table, when included, shows the distance from the final approach fix to the MAP.

Timing for instrument approaches is not necessary as long as there is no unable RNP alert displayed.

Hi patrick if you fly the 737 ngx you don't need to use timing

 

Timing During Approaches

 

Since FMC use is appropriate for instrument approach navigation, timing is not the primary means to determine the missed approach point. The probability of multiple failures that would result in timing being the only method of determining the missed approach point is remote. However, some regulatory agencies may still require the use of timing for approaches. The timing table, when included, shows the distance from the final approach fix to the MAP.

Timing for instrument approaches is not necessary as long as there is no unable RNP alert displayed.

 

He was referring to the box providing the rates of descent in the next column over from the one you're fixating on, which is precisely the topic being discussed, is it not?  Come on now... 

Rate of descend, not timing! I see oops.