Civilian freighters are versions of passenger aircraft. Some of them, are
production built and others, are used passenger aircraft converted to freighters
(P2F). Converting military or passenger aircraft to freighters is going back to the
early era of commercial aviation. In 1919, American Railway Express, used a
converted Handley-Page bomber in an attempt to fly 1,100 pounds of freight
from Washington, D.C., to Chicago. In reality, Air cargo did not pick up
significantly until after WWII. With plenty of ex-military aircraft such as DC-3/C-
47, DC-4/C-54s on the market in the postwar period, it wasn't surprising that
some of them were converted to commercial freighters. Later, other piston
engine aircraft, as the Lockheed Constellation and DC-6 (including the Freddy
Laker Carvair) were also converted to commercial freighters.
The turboprop era was dominated by two P2F aircraft: the Lockheed L-188 and
the Convair 580/5800. Years later, there were also additional turboprop P2F
programs: ATR-42/72, BAe-748/ATP, SAAB 340 and few Bombardier Q400's.
Quite a few jet models were feedstock to a number of P2F programs: B727-
100/-200, B737-200/-300/-400, B707, B747-100/-200/-400, DC-8, C-9, DC-10,
MD-11, MD-80, BAe-146, A-300B4, A-300-600, A-310, and few Bombardier
CRJ's. Nowadays, there are several P2F conversion programs in the pipeline:
A-320/A321, A-330, B737-700/-800.
When an aircraft is almost "reaching its age" and have completed its useful
operational service as passenger jetliner, it can either be scrapped or recreated
again in a different segment. Converting passenger aircraft into a freighter, is a
way to extend the economic life of an aircraft. Quite a number of cargo airlines
choose to operate a first-hand quality converted freighter. The converted
freighters meet the high dispatch reliability required, they are more economical
for the company and they can gain the same amount of revenue without using
an expensive production freighter.
Historically, more than 90% of narrowbody freighters are being converted
aircraft. Mid-size freighters are divided 50:50 between production and converted
freighters. Only one-third of the large widebody freighters are converted
passenger aircraft. From the 2008 crisis, the trend is to increase the portion of
the new production freighters in this segment (converted freighters are
considered less fuel efficient).
Most conversions are to freighters, but few small size jets were converted to
combis (cargo and passengers on the main deck) and fewer to Quick Change
(Dual-use aircraft carrying passengers in daytime and freight at nighttime).
Traditionally, production freighter are designated with the letter F. Converted
passenger aircraft are designated with the letters SF. In recent years, 3
conversion houses use their own designations:
BCF – Boeing Converted Freighter.
BDSF - Bedek Special Freighter.
PCF - Precision Conversions Freighter.
P2F conversion involves:
• Changing the aircraft mission and configuration and adapting it to a new
• Major structural modifications as required for the new configuration.
• Installation of specific systems as required for the new missions.
• Certification - STC (Supplementary Type Certificate) or amendment of a
Type Certificate (TC).
Typical conversion task includes, but are not limited to:
• Removing from the passenger aircraft anything that is not needed
anymore, like interiors equipment and furnishings (seats, galley, toilets,
stowage bins, side and ceiling liners, carpet flooring, oxygen, overhead
consoles, entertainment system act.).
• Removing or deactivating of passenger doors.
• Replacing or reinforcing floor beams as required to meet cargo loads
• Installation of the Main Deck Cargo Door (MDCD) with safety vent doors
and replacing or reinforcing surround structure. If there is no reason that
prevents it, the MDCD is placed on the fuselage left-hand side in front of
• Installation of hydraulic/electric MDCD operation system (usually
hydraulic on narrowbody freighters).
• Installation of 9g rigid barrier / Net.
• Modifying area behind the cockpit for supernumerary seating.
• Modification of the cargo compartment (new cargo lining, ceiling &
lighting, floor, drain system etc.)
• Modification of the cargo compartment to "Class E".
• Installation of one-minute smoke detecting system.
• Installation of non-powered / powered (powered in large widebodies)
Cargo Loading System (CLS), allowing loading of various arrangements
of ULDs cargo within the main deck.
• Modification cockpit equipment and avionics as required.
• Installation of lightweight window plugs.
Aircraft Type Suitability – Some Parameters
- Density (Payload / Volume)
- Fuselage Cross-section
- Weights / structural limitations
- Ground Stabilization
- CG “flexibility"
- Electric / Hydraulic / ECS Provisions<
- High production quantity
- 10 - 20 years old.
- Reliable airframe / engine.
- Low capital cost.
- Noise compliant.
- Compatibility with other freighters (iinterline).
- Production freighter version as a modeel for design could be an advantage.
- Infrastructure commonality
Some Key Considerations for Particular Aircraft Stability for Conversion.
- Aircraft age (barrier in certain counttries), hours/cycles.
- Fleet commonality - sister ship.
- Remaining design life (hours, cycles, age).
- Maintenance condition and “history”.
- Weights / CG / structural limitations.
- SSID Program or other program effects.
- Impact upon existing AD’s and SB’s.
- Relevant STC / Factory Modes.
- Ownership “complications".
P2F Conversions Suppliers
Traditionally, a P2F conversion can be carried out by:
- The aircraft manufacturer (OEM).
- A third-party contractors or independentt companies that enter into
cooperation agreements with the OEM.
- Third-party contractors that develop theeir conversion solutions
In recent years, as a result of Boeing charging "access fees", and the modern
aircraft technical complications (Fly-By-Wire, etc.), more and more conversion
houses work in collaboration with the OEMs or authorized by the OEMs.
Boeing and Airbus, the OEMs, sometimes provide the engineering task for TC
Amendment / STC.
EFW, is Airbus conversions house. In recent years EFW teamed with ST Aero).
Boeing is using a case-by-case model for their conversions. For example, ST
Aero and IAI (757 for DHL), ST Aero (757 for FedEx), Aeronavali and ST Aero
(DC-10, MD-11), TAECO, KAL Aerospace and SIA Engineering (747-400BCF),
and ST Aero (767-300BCF).
Non-OEM companies using different methods, such as IAI, use their strong in-
house engineering capability. Others, as Precision and AEI, are outsourcing the
engineering. IAI, Pemco, and AEI use their facilities for conversions, but also,
outsource conversions touch labor for less expensive sites.
The Non-OEMs use
similar methods for the conversion kit fabrication.
Major Non-OEMs in recent years are: AEI (737-300/-400, MD-80, CRJ),
Aeronavali (MD-11, DC-10 for Boeing), IAI (BDSF-747-400, 767-200/-300, 737-
300/-400), Pemco (737-300/-400, 757-200), Precision (PCP-757), ST Aero (DC-
10, MD-11, 757, 767, for Boeing), TAECO (747-400 for Boeing, 737-300/-400
for Pemco), and PACAVI (A320/A321).
Among the conversion sites ("touch labor") in recent years are: VEM (Brazil),
GAMECO, AMECO, TAECO, STAECO, Boeing Shanghai (China), Flightstar,
HAECO, Dotan, Goodyear/AeroTurbine (USA), COOPESA (Costa Rica), and
KF Aerospace (Canada).
The price of the converted freighter must be attractive in order to compete with
production freighter. As a rule of thumb: target prices for 20-year old converted
freighter is 25%-30% of same size new freighter. Examples:
- Small: US$10-$12 million
- Medium nnarrowbody: US$15-$20 million
- Medium widebody: US$20-$30 million
- Large: US$55-$65 million
(The price of a new production medium widebody is over US$70 million, and a
new production large widebody is over US$150 million).
P2F Conversion Programs
In the jet era of commercial flight, two types of converted freighters
accompanied the development of the Air Cargo industry. The first was the B-727
which was the backbone of small and medium freighters (106 converted B727-
100 and 350 converted B727-200). The second, in the larger size segment, was
DC-8 in which more than 200 (all models) were converted to freighters.
Quite a number of 727s/DC-8s were successfully operated for more than 40
years. When the time comes to phase them out, there were no aircraft with
similar sizes that can replace them and the industry had to move to larger or
Over the years, there were other P2F programs, but none have come to the
727’s/ DC8's figures. Some P2F programs have reached significant numbers: B-
737-300/-400 (more than 220), B-757-200 (more than 190), MD-11 (121), DC-10
A very important factor in the success of a P2F conversion program is timing.
Following are 3 examples of cases that timing had a crucial influence on their
Airbus A300B4– this model was not considered popular as a passenger aircraft
and airlines phased them out relatively young. But it was at the right time to
become a freighter as no other aircraft in its size was available. 74 A300B4s
were converted in two P2F programs (1987-2000) and many of them have flown
as freighters for more than 10 years. The main cause was timing.
Boeing B747-400 – Industry experts predicted that the converted 747-400
would be a success as a favorable replacement for the aged 747-200 freighters.
However, the 2008 aviation down-time, the high fuel price and the low-yield
market made it difficult to compete with the more efficient 777 and 74-8
freighters. A total of 79 747-400s were converted. From 2012, the demand
shrunk to zero. Quite a number of converted 747-400s along with a production
747-400 were stored. It wouldn't be an exaggeration to say that the 747-400
P2F programs died and there is no way they come back to life as they missed
the "conversion window". Again, the main cause is timing.
Boeing B767-300 – Industry experts predicted P2F a rosy future. Two
conversion programs were established. In June 2008, ANA took delivery of the
first 767-300BCF from Boeing, and in Jan. 2010 euroAtlantic airways took
delivery of the first 767-300BDSF from M&B Conversions (a joint venture
company of IAI Bedek and Mitsui & Co. of Japan).
Unexpectedly, only 20 aircraft were converted. The rate of conversions in both programs was very low (some years – zero conversions). A shortage of 767-300 feedstock was the main reason. Long delays in the 787 program caused airlines to continue to fly the 767-300s that had to be phased out and become the feedstock for conversions. The shortage of 767-300s caused high prices for the few proposed for selling. Again – timing. But it seems that the 767-300 is a “late bloomer”. In 2015 the two conversion programs received orders and the conversion lines came back to life.
Jacob Netz is a Senior Consultant at Air Cargo Management Group.
Previously worked for Israel Aerospace Industries - BEDEK Aviation Group as the Analysis & Strategy Director of Freighter Conversions.