Vertical Rate Reduction

[renzo.zubi]

Hallo!

How is the ROC/ROD (rate of climb, rate of descent) of jet aircraft handled by different operators when approaching a cleared altitude or FL? Do they stay in "open" flight-guidance modes or do they change the modes to "vertical speed" or "path" to reduce the probability of a level bust or a TCAS resolution advisory when other traffic is close by' What are the ROC/ROD-limitations by different civil aviation authorities?

[maggot738]

Our SOP is to limit the rate of climb or descent in busy TMA's to 2000fpm with 2000 feet to altitude and 1000fpm within 1000 feet of cleared level. In RVSM airspace, if VNAV is doing the right thing and the rate of climb is less than 1500 fpm then the preferred mode is VNAV as this provides all the safety margins that a VS climb does not. This is all related to avoiding unneccesary and unwanted TCAS TA's. (or indeed RA's at high rates of climb or descent). Hope this helps.

Maggot

[TopSwiss 737]

We use the following in the company I work for.

Excerpt from POLICY AND PROCEDURES FOR THE USE OF TCAS/ACAS:
"In order to avoid the generation of erroneous warnings, vertical speed
should be limited to no more than 1 500 fpm when within 2 000 ft of the
assigned altitude and in the close proximity (ca. 2 NM) of other aeroplanes."

RVSM:
"During the last 1 000 ft during climb and descent to the cleared flight
level, the rate of climb or rate of descent should be within 1 000 ft/min.
The overshoot or undershoot of the cleared flight level shall not exceed
150 ft."

TS737

[shortfuel]

What are the ROC/ROD-limitations by different civil aviation authorities?

That's a partial answer: (extract from an old 2007 UK AIC):
For me, it's just good airmanship to apply it everytime/anywhere.

http://nsa18.casimages.com/img/2010/08/15/10081505174727291.jpg (http://www.casimages.com)

[flyby797]

There is also a new amendment 33A to ICAO annex 6, effective july 2009. It is a recommendation:
4.4.10 Aeroplane operating procedures for rates of climb and descent

Recommendation.— Unless otherwise specified in an air traffic control instruction, to avoid unnecessary airborne collision avoidance system (ACAS II) resolution advisories in aircraft at or approaching adjacent altitudes or flight levels, operators should specify procedures by which an aeroplane
climbing or descending to an assigned altitude or flight level, especially with an autopilot engaged, may do so at a rate less than 8 m/sec or 1 500 ft/min (depending on the instrumentation available) throughout the last 300 m (1 000 ft) of climb or descent to the assigned level when the pilot is made aware
of another aircraft at or approaching an adjacent altitude or flight level.