b. With the approval of both the procuring activity and the applicable fuel technical authorities listed below,
up to a total 50 volume percent of the inished fuel may consist of Synthesized Parafinic Kerosene (SPK) derived
from a Fischer-Tropsch (FT) process meeting the requirements of MIL-PRF-83133, Appendix A or SPKs derived
from Hydroprocessed Esters and Fatty Acids (HEFA) meeting the requirements of MIL-PRF-83133, Appendix B.
HEFA-SPK has also been called Hydroprocessed Renewable Jet or Hydrotreated Renewable Jet (HRJ), and for
the purpose of this speciication, the terms are considered interchangeable. Finished fuel containing FT-SPK or
HEFA-SPK shall contain additives in accordance with 2.4. Finished fuel containing FT-SPK shall conform to the
properties of MIL-PRF-83133, Table A-II in addition to those of MIL-PRF-83133, Table I. Finished fuel containing
HEFA-SPK shall conform to the properties of MIL-PRF-83133, Table B-II in addition to those of MIL-PRF-83133,
Table I. During the platform certiication/approval process, permission from both procuring activity and the applicable
fuel technical authority listed below shall be obtained prior to the use of a inished fuel containing SPK. The Army is
currently in the process of certifying/approving their respective aircraft/equipment/vehicles.
Cognizant activities for the US Army:
US Army Ground: Fuels and Lubricants Technology Team, RDECOM-TARDEC, RDTA-DP, Building
210, 6501 E. 11 Mile Road, Warren, MI 48397-5000.
US Army Aviation: US Army RDECOM, Attn: RDMR-AEP, Building 4488, Room C-211, Redstone Ar-
senal, AL 35898-5000.
d. Procuring Activity: Product Technology & Standardization, DLA Energy, Rm 2843, 8725 John J. Kingman
Road, Fort Belvoir, VA 22060.
a. Insure that the approval of the pilot is obtained prior to servicing an aircraft with an emergency fuel. The
aircraft should be placarded in a conspicuous manner indicating the type emergency fuel used.
b. Gasoline fuel may be used in some turbine engines under emergency conditions, however there may be
associated restrictions or special precautions outlined in the operator s manual.
c. The use of straight unleaded gasoline may shorten the operating life of combustion parts; therefore, its
use between scheduled internal inspections is limited. Refer to Table 2-3 notes. When the allowable operating
time has been reached, the use of unleaded gasoline must be discontinued pending result of internal inspection.
Unleaded gasoline leaves combustor parts clean; therefore, no special cleaning is required between scheduled hot
end inspections. Two parts of unleaded gasoline mixed with one part of kerosene produces a fuel which is preferred
above that of straight unleaded gasoline. This mixture should be identiied in the fueling record.
d. Leaded gasoline, either straight or mixed with unleaded fuel in any proportion, will deposit a layer of lead
compounds on combustor parts. These attack the underlying metal and also act as an insulator which reduces
combustion eficiency and causes the formation and deposition of carbon. Therefore, the operating time between
scheduled hot end internal inspections is limited. Refer to Table 2-3 notes. Continued use of leaded aviation gasoline
or jet fuel in excess of 1% of aviation gasoline, may cause failure of the vaporizing tubes and subsequent turbine
blade damage resulting in a safety-of-light hazard. The continued use of jet fuel contaminated with less than 1%
of aviation gasoline is permissible in these aircraft. If the permissible accumulated operating time is exceeded, a
special cleaning and inspection becomes mandatory. The cleaning and inspection may be delayed for 10 operating
hours provided only recommended fuel is used during the delay. A fuel mixture which contains over 10% leaded
gasoline shall be identiied as all-leaded gasoline on DA Form 2408-13, Aircraft Inspection and Maintenance Record.
e. Gasoline containing TCP (Tricresyl Phosphate) in addition to TEL (Tetraethyl Lead) is more detrimental to
combustor parts than gasoline containing TEL only. Deterioration of combustor parts occurs at least twice as fast
when TCP is added to leaded gasoline. Operating time on gasoline with TCP is therefore limited to one-half the time
allowed on leaded gasoline without TCP and shall be clearly indicated in the fueling records. Whenever fuel with
TCP is used, special cleaning and inspection of combustor parts is mandatory.
f. For information concerning the cleaning of combustor parts after the use of emergency fuels, refer to the
applicable maintenance manuals.