ISTAT Jetrader - Winter 2019 - 44

APPRAISAL

CF34-8 Engine
Oliver Stuart-Menteth
ISTAT Certified Senior Appraiser
Fintech Aviation Services
www.fintech.aero

Photo courtesy of GE Aviation

W

hen GE
developed
the high
bypass
CF34
engine
from
the military TF34 variant in the early
1980s for the Canadair (Bombardier)
Challenger 601 business jet, it was not
anticipated that the commercial model
would undergo such a large number of
iterations, resulting in a thrust range
from 8,700 to 18,800 pounds. The
resulting CF34-3, -8 and -10 variants
power the Bombardier CRJ100/200,
CRJ700/900/1000, Embraer E-170
and E-190 family, and COMAC ARJ21 aircraft - of which there are
approximately 3,000 - resulting in
over 6,000 engines in active service.
It is the most popular regional jet
engine, easily surpassing the RollsRoyce Allison AE3007 (Embraer
ERJ-135/145), of which there are
approximately 1,800 in service.
Of all the variants, the CF348 is the most popular with over
4,000 powering the Bombardier
CRJ700/900/1000 and Embraer
E-170/175 fleet. The major -8 variants
and their parent aircraft are listed
in Table A. The larger CF34-10
exclusively powers the E-190/195
family and internally mirrors the design
of the CFM56, breaking the trail of
commonality of previous iterations.

44

* T H E O F F I C I A L P U B L I C AT I O N O F I S TAT

While GE continues to develop permanent
solutions, combustion liner release remains the primary
driver for unscheduled removals.
The largest physical difference in
the -8 model hierarchy lies between
the initial -8C1 and the later -8C5
variants. As a consequence of reduced
hot section durability, the -8C1 exhibits
a vastly reduced average on wing time,
effectively increasing the cost per flight
hour (FH) to an unacceptable level.
In response, GE developed Service
Bulletin 72-0130, which, among other
modifications, installs improved high
pressure turbine blades and nozzle
guide vanes, and provides the engine
with a new data plate confirming -8C5
status. The majority of the original
-8C1 engines are now believed to have
been upgraded to the more reliable
-8C5 variant.
The introduction of the -8C5 engine
into the CRJ700 production line in 2002

presented GE with an opportunity to
permanently resolve two issues that
have plagued this variant since entry
into service in 1999, namely fan blade
vibrations and combustion liner release.
Unfortunately, these two issues remain,
and while GE continues to develop
permanent solutions, combustion liner
release remains the primary driver for
unscheduled removals. Notwithstanding
these two issues, the engine is
considered to be extremely robust and
generally requires minimal unscheduled
on-wing maintenance during A and C
checks. Depending upon utilization and
the operator's profile, most airlines will
complete one midlife shop visit (SV)
at 12-14,000FH with a performance
restoration occurring at approximately
20-22,000FH, at which point all the life

Table A
Model (Thrust lbs)

Aircraft Application

Model (Thrust lbs)

Aircraft Application

-8C1 (12,670)

CRJ700

-8C5A2 (14,050)

CRJ900

-8C5B1 (12,670)

CRJ700

-8C5A1 (13,630)

CRJ1000

-8C5 (13,360)

CRJ900

-8E5 (13,420)

ERJ -170/175

-8C5A1 (13,630)

CRJ900

-8E5A1 (14,050)

ERJ- 170/175

Source: FAA Type Certificate No E00063A
http://www.fintech.aero
ISTAT Jetrader - Winter 2019

Table of Contents for the Digital Edition of ISTAT Jetrader - Winter 2019
