Process Explanation of the Quick Start Auxiliary Power Unit System on the KC-135R Aircraft

Richard Bogdan

TECM 4700.001: Writing in the Sciences

October 9, 2015

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The Quick Start Auxiliary Power Unit System on the KC-135R Aircraft (general audience)

Introduction

Defining the Quick Start Auxiliary Power Unit System

In the early 1980’s, the United States Air Force modified their KC-135R Stratotanker aircraft by installing two quick start auxiliary power unit systems (QSAS). These QSAS act as external

generators which provide electrical and hydraulic power throughout the aircraft. The QSAS was installed in order to provide quick and reliable power to the aircraft in times of need or for emergencies. This document describes in general terms, the process of operating the QSAS on the KC-135R Stratotanker. The only required material for accomplishing this task is the instructions found in technical order (T.O.) 1C-135(K)R-2-16JG-2. There are three major stages in operating the QSAS. These stages include: preliminary checks, turning on the QSAS, and shutting off the QSAS.

Step-by-Step Description

1. Preliminary Checks Operation of the QSAS begins with preliminary and safety checks to prevent harm to both the aircraft and personnel. Carefully read the warning and caution sections of

T.O. 1C-135(K)R-2-16JG-2 to confirm that it is safe to start the QSAS.

2. Start the QSAS The second step of operating the QSAS is turning it on by positioning the START/STOP switch

into the START position. This will increase the exhaust gas temperature (EGT) to 1200°F which will activate the RDY (ready) light allowing you to use electric and hydraulic power throughout

the aircraft.

3. Stop the QSAS After you are finished using the QSAS, position the START/STOP switch to STOP. This will cause the QSAS to go into cooldown mode for thirty seconds before shutting off.

Conclusion

This document has reviewed the normal operations of the QSAS found on the KC-135R

Stratotanker. The stages went over in this document include the preliminary safety checks, the operation of the QSAS, and the shutdown of the QSAS.

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The Quick Start Auxiliary Power Unit System on the KC-135R Aircraft (upper-level audience)

Introduction

In the early 1980’s, the United States Air Force modified their KC-135R Stratotanker aircraft by installing two quick start auxiliary power unit systems (QSAS). These QSAS act as generators

which provide electrical and hydraulic power throughout the aircraft, eliminating the need for ground based power from an external source. The QSAS was installed in order to provide quick

and reliable power to the aircraft in times of urgency (i.e. quick takeoffs when the aircraft needs to be in flight within 30 minutes) or for emergencies (if an engine fails mid-flight.) This document describes the process of operating the QSAS on the KC-135R Stratotanker. The only required material for accomplishing this task is the instructions found in technical order (T.O.) 1C-135(K)R-2-16JG-2. There are three major stages in operating the QSAS. These stages include: preliminary checks, turning on the QSAS, and shutting off the QSAS.

Step-by-Step Description

1. Preliminary Checks

Operation of the QSAS begins with preliminary and safety checks to prevent harm to both the aircraft and personnel. Carefully read the warning and caution sections of T.O. 1C-135(K)R-2-16JG-2 to confirm that it is safe to start the QSAS. Failure in doing so could cause serious injury, death, or up to millions of dollars in damages to both the QSAS and

aircraft. 2. Start the QSAS

The second step of operating the QSAS is turning it on by positioning the START/STOP switch into the START position. This will open both of the QSAS exhaust doors that lead outside of the

aircraft allowing exhaust and excess fuel to be dumped outside of the aircraft. Exhaust gas temperature (EGT) will rapidly increase to 800°F where it will remain that temperature for

about a minute before increasing and stabilizing at 1200°F. When the QSAS EGT reaches 1200°F it will activate the RDY (ready) light on the console allowing you to turn on the generator switch which will provide electric and hydraulic power throughout the aircraft.

Note: In temperatures 40°F or below, a frozen door check must be performed in order to ensure that both exhaust doors of the QSAS can be opened. This check requires the aircraft personnel to carefully rotate the QSAS door actuator by hand, making sure not to cause any damage to the device.

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3. Stop the QSAS

After you are finished using the QSAS, the generator switch will be placed to OFF and the START/STOP switch will be placed in the STOP position. This will cause the QSAS to go into

cooldown mode for approximately thirty seconds as engine rpm begins to drop. After the thirty second cooldown period, the QSAS doors will close, ensuring that the QSAS has successfully

shut down.

Note: There is a QSAS emergency stop, but should only be used when the QSAS is on fire. This will immediately cutoff fuel from being pumped into the QSAS and will set off the two fire bottles located above each QSAS. Setting off the fire bottles in non-emergency situations will cause severe damage to the QSAS, requiring a full replacement of all components.

Conclusion

This document has reviewed the normal operations of the QSAS found on the KC-135R Stratotanker. The stages went over in this document include the preliminary safety checks, the operation of the QSAS, and the shutdown of the QSAS. The Quick Start Auxiliary Power Unit System is an important component of the KC-135R aircraft. It allows all four engines to be

started without the need of an external power source, provides electrical power for lights and radio communications, and handles all components that function hydraulically like rudders,

brakes and the refueling pump. The KC-135R can still be operated in emergency situations without both of its QSAS, however, it is not recommended. That is why the operational

knowledge of the QSAS is necessary for all aircraft mechanics on the KC-135R and not just jet engine specialists.