Airliner World – May 2018

The -200 series proved
popular with a variety of
British carriers including
Air Europe, Air UK Leisure,
Ambassador Airways,
British Airways, Caledonian,
Dan-Air and Inter European.
London Luton-based
Britannia Airways operated
around 45 different
examples, including G-BECG
(c/n 21335), which was
delivered new in April 1977.
KEY COLLECTION

Northern Air Cargo’s Boeing
737-232A freighter N321DL
(c/n 23093) is equipped
with a gravel kit, including
deflectors on the nose and
main landing gear and
vortex dissipaters to protect
the engines from ingesting
debris. The modifications
were popular with carriers
serving remote regions – at
its peak of operation, 737s
were completing more than
2,000 movements a year
from unpaved runways.
AIRTEAMIMAGES.COM/
DARREN HOWIE

32 AIRLINER WORLD JUNE 2018

Key Dates

Family Original Classic Next-Generation MAX

Series 100 200 300 400 500 600 700 800 900 7, 8, 9, 10

First flight Apr 9, 1967 Aug 8, 1967 Feb 24, 1984 Feb 19, 1988 Jun 30, 1989 Jan 22, 1998 Feb 9, 1997 Jul 31, 1997 Aug 3, 2000 Jan 29, 2016

First delivery Dec 28, 1967 Dec 29, 1967 Nov 28, 1984 Sep 15, 1988 Feb 28, 1990 Sep 18, 1998 Dec 17, 1997 Apr 22, 1998 May 15, 2001 May 22, 2017

Launch customer Lufthansa United Airlines US Air Piedmont Airlines Southwest Airlines SAS Southwest Airlines Hapag Lloyd Alaska Airlines Batik Air

Last delivery Nov 2, 1969 Aug 2, 1988 Dec 17, 1999 Feb 25, 2000 Jul 21, 1999 Aug 31, 2006 - - - -

Units produced 30 1,114 1,113 486 389 69 1,280 4,853 510 86

On order - - - - - - 5 321 569 4,230

above normal operational levels.

As a quick fix, engineers reinforced

the rear spar on the first two test aircraft

to increase this figure up to 50%, but

further delays were encountered

after the modified wing had to be put

through another structural overload

cycle. Additional design refinement

enabled the manufacturer to squeeze

even more performance from the wing,

an essential development after the

stronger but heavier spars increased

weight and compromised the 737’s

short-field performance – one of its

major selling points.

Certification for the series -100 was

received from the FAA on December 15,

1967, with approval for the longer -200

following six days later. Remarkably, the

manufacturer met its original certifica-

tion schedule though the first example

was not delivered to Lufthansa until

December 28, too late for Boeing's

planned end-of-year entry into service,

which came the following February.

Growing Appeal

Boeing worked throughout 1968 to

develop a longer-term solution to the

excess drag issue. The additional 500lb

of thrust offered by the more powerful

P&W JT8D-9 turbofan again delivered a

quick fix, but more substantial chang-

es were necessary. After almost a year

of wind tunnel and flight testing, sev-

eral aerodynamic modifications were

made. This included redesigned engine

nacelles and wing fairings, improved

airflow over the lower edge of the wing,

vortex generators on the rear fuselage

and redesigned thrust reversers.

These upgrades were introduced as

standard from aircraft number 135 and

ushered the 737 into a new era – pay-

load and range had been improved

significantly, while cruising speed and

short-field performance were far closer

to the original specifications laid down

by Boeing.

Successful as the changes were, the

small capacity of the 737-100 meant the

variant attracted just 30 orders. The

bigger -200 offered a much more eco-

nomical proposition, and Boeing moved

to maximise the type’s appeal. This

included two special variants, the -200C

convertible and 200QC ‘quick-change’,

both of which were equipped with a

large cargo door in the forward fuse-

lage, specialist handling equipment and

reinforced cabin floors, enabling mixed

passenger and freight operation or rapid

reconfiguration between the two.

Among the more unusual options

offered by Boeing was the ‘Unpaved

Strip Kit’ (or gravel kit). Rolled out in

early 1969, the modification included

installing gravel deflectors on the nose

and main landing gear to protect the

fuselage and wings, reinforcing the

airframe and antennas, applying an

abrasion-resistant Teflon-based paint

on undersurfaces, a retractable lower

anti-collision light and vortex dissipat-

ers to protect the engines from ingest-

ing debris.

The protective equipment added to

the 737’s versatility and, according to

Boeing, limited extra maintenance

costs associated with flying to and from

semi-prepared airstrips (with, for exam-

ple, additional tyre wear and paint loss)

to just $15 per landing. It was certain-

ly popular with carriers serving remote

regions – at its peak of operation, 737s

were completing more than 2,000

movements a year from unpaved

runways.

Advancing the Design

With the 737 established and in

service, Boeing set about a radical

development programme, producing