Operations into La Paz - Elevation 13,325ft
A fascinating account of how to operate a 737 into an airfield of such high elevation by Capt Daniel M. Lopes, Varig Airlines, July 2000.
Here at Varig, we have a daily flight (exc. Sun) from
SBGL (Galeão, RJ) to SLLP (La Paz) with stops in SBGR (São Paulo Int'l)
and SLVR (Santa Cruz de La Sierra, Bolivia). It's a routine flight until SLVR.
*** Updated 20 Nov 2018 ***
From SLVR some procedures apply:
Flight time to La Paz is 50 minutes. We have to use a
B737-300 with 22k engines and 225mph tires. Pilots must be qualified by a
Captain, with previous experience for this flight, before a
"solo" flight. It's required to make a full IRS alignment and
check if some specific positions are in data base. For airplanes with CPCS
(pressurization system panel) set SLVR altitude minus 200ft before departure and
after takeoff set cabin altitude to 9000ft. Over position TORAX (about 55nm to
La Paz) adjust cabin to 12900ft for landings on runway 10 or 13100ft for rwy 28.
For digital pressurization control you can use AUTO mode and set LAND ALT to
9000ft. Over TORAX use same altitudes described above. When cabin altitude
reaches 10000ft pilots must wear oxygen masks (Norm position) until shutdown
It's forbidden to make weather deviations during descent,
if necessary, maintain cruise level, make any deviation required and descend
in a holding pattern over La Paz VOR, obviously following a coordination with
ATC. (Unfortunately an Eastern Airlines B727-200 crashed during a
descent, making weather deviations. This airplane hit a 21184ft-high mountain in January
1985). At least, just prior to descend, PNF must set VHF NAV to manual and
EHSI mode in Exp or Full raw data. FL 230 is the minimum altitude until 20nm to
PAZ VOR, after 20nm it's possible to descend to 18000ft and start a VOR/ILS
procedure (No radar vectors). Inhibit GPWS (Flap) because only flap 15 is
approved for landing due to landing climb limits and do not use autobrake
system. Unless any abnormal condition occurs, proper pilot technique is
"Maximum reverse thrust, within engine limits, and minimum brakes",
this is a 4000m-long runway, and this procedure works well and brakes and tires
do not warm and affect turn around (anyway you need to check "Max quick
turnaround weight table" after landing). Go around and max takeoff N1
values must be checked using an special table if required.
Runway 10 should be used even with light tailwind (within
limits and checking tire speed limit, too) because there isn't an instrument
procedure for runway 28 (just circling), and it isn't comfortable to make a
circling approach to runway 28 due to a turbulent air near threshold (it's very
close to a high terrain, and you fly over a valley where city of La Paz is
and downdrafts are very usual). Missed approach for runway 10 is a sharp right
turn to avoid Ilimane Peak, described before (Eastern).
For departure, full alignment and oxygen masks are
also required and "High altitude airport start procedures" must be
followed. Rolling takeoff is not permitted. There are special engine failure
climb patterns, for
runways 10 and 28. Improved climb, flaps 1 takeoff and no
engine bleed must be thoroughly checked to take the best weight and
performance advantage. Performance data is based on AFM Appendix 25 and 37LP.
There are also special enroute procedures and
charts to fly in/out La Paz in case of pressurization failure and engine
inoperative (with FMC on or off) and some additional details.
The most amazing thing is to make this flight during
clear weather. During initial approach you fly over high terrain with a lot
of snow and it's possible to see, not so far, Titicaca lake, but certainly you
become very impressed when turning on final to land on runway 10 and the big
wall (Ilimane peak) is just behind. An outstanding view !!!
The airplane reaction is very slow and you always must be
prepared in advance. Due to the high altitude TAS is higher than usual, but
engine response does not correspond as we are accustomed on a sea level flight.