@oceancrosser: because the PACK OFF/ON drill is very simple, thus for economical reasons it is a very common operating technique. Well documented by the manufacturer.
@Bus Driver Man: Agreed. Moreover, the 2.1% gradient is a certification requirement FAR/CS 25 for approach climb (G/A conf, L/G UP, OEI). The actual REQUIRED performance is 2.5% to keep yourself inside (well, above is a better word
) the premises of PANS-OPS ICAO Doc 8168 - obstacle clearance for the missed approach segment.
Properly done books / EFB should have the QRH table i and EFB application modified to 2.5 per cent. Let's not start about OEI ACC ALT on G/A.
