Military

 


The Utility Helicopter Mission Is Still Essential

CSC 1993

SUBJECT AREA - Aviation

EXECUTIVE SUMMARY

Title: The Utility Helicopter Mission is Still Essential

Author: Major Joseph G. Doyle, United States Marine Corps

Thesis: The Marine Corps must replace or upgrade the UH-1N and purchase enough

aircraft to meet operational tempo.

Background: The utility helicopter mission is essential to support MAGTF operations.

The UH-1N has been performing this mission for almost 20 years and because of limited

capabilities and inadequate numbers presently cannot conduct it satisfactorily. The

Huey's replacement, VMAO, is projected to enter the fleet in 2015. Considering the

likelihood of increased reliance on the Marine Corps to conduct operations ranging from

low intensity conflict to humanitarian relief, the demand for a utility helicopter will also

increase. The UH-1N will not be able to support this high operational tempo in the

future.

Recommendations: The Marine Corps should purchase the H-60 Black Hawk and

maintain a T/E of 12 utility helicopters in each HMLA squadron.

OUTLINE

Thesis: Due to limited capabilities and insufficient airframes, the UH-1N cannot

effectively conduct the utility mission for the Marine Air Ground Task Force (MAGTF);

therefore, a new aircraft must be purchased or a mid-life upgrade conducted and

adequate numbers of aircraft purchased.

I. Evolution of the UH-1N

II. Utility mission is essential to MAGTF operations

A. MAGTF aviation assets

B. Validity of the utility mission

C. Missions assigned to UH-1N

Ill. Dwindling assets

A. Out-of-production model

B. Aircraft attrition

IV. Continued high operational tempo

A. MEU deployments

B. Training

V. Aircraft structural deterioration

VI. Limited capabilities

A. Airspeed

B. Payload

C. Endurance

VII. Utility platform options

A. UH-1N mid-life upgrade

B. Purchase a new aircraft, H-60

C. Procurement factors

D. Analysis

VIII. Insufficient aircraft to support demand

IX. The politics of procurement

Due to limited capabilities and insufficient airframes, the UH-1N cannot effectively

conduct the utility mission for the Marine Air Ground Task Force (MAGTF); therefore, a

new aircraft must be purchased or a mid-life upgrade conducted and adequate numbers

of aircraft purchased. The "Huey" has had a distinguished history. A workhorse in

Vietnam, it proved versatile and enduring in a variety of assigned missions. As a mix of

helicopters was added to the Marine Corps inventory, the UH-1 continued to prove

invaluable at "filling the gaps." The Huey performed the crucial mission tasks for which

the other aircraft were neither configured nor suited.

In the early 1970's the Marine Corps received the latest model, the UH-1N, which is

still in service after almost 20 years. In the 1980's the Huey performed well but in

recent years there has been a marked reduction in the quality of its performance. High

utilization with no mid-life upgrade or service-life-extension program (SLEP) has resulted

in airframe fatigue and limited capabilities. Compare the Huey to the capabilities of new

model helicopters in avionics, airspeed, and cargo load and a wide gap is obvious. The

replacement for the UH-1N, the Advanced/Attack/Observation/Utility/Platform (VMAO),

is due to enter the fleet circa 2010-2020.

Considering future budget constraints and project funding competition this date could

be much further out. Several questions must be answered. Is the utility mission still

essential? Can the remaining three Marine helicopters, CH-53, CH-46 and AH-1,

accomplish the utility mission? Can the Huey stay in service until 2010 without an up-

grade? Would it be more cost effective to conduct a mid-life upgrade or purchase a

new type aircraft to perform the utility mission?

Is the utility mission still essential? MAGTF aviation employs a complete assault

support helicopter capability. Heavy logistics is performed by the CH-53 while the bulk

of the troop transport is assigned to the CH-46. Anti-mechanized operations, helicopter

escort and close-in-fire-support (CIFS) are tasked to the AH-1 W. ln any operation there

are numerous tasks which, although simple, are essential to the success of MAGTF

operations. These tasks are assigned to the utility helicopter. The UH-1N's primary

assigned mission is command and control for the helicopter assault element. The Huey

accompanies the helo assault wave to the objective with the assault support coordinator

(airborne) (ASC(A)) and often the heloborne unit commander (HUC) onboard. During the

landing and consolidation phase, if tactically feasible, the UH-1N enables the ground

commander to observe his objective and, when ready, land at his command post. The

ASC(A) ensures the smooth flow of aircraft into the objective area.

The Huey is also assigned several secondary missions that include troop transport,

medical evacuation, search and rescue (SAR), armed escort (ground and airborne), CIFS

and airborne supporting arms coordinator. (3:1) These missions can be performed by

the other Marine helicopters, but the UH-1N provides flexibility and allows the most

economical use of aviation assets. The airframe is relatively cheap to fly and in the

high-demand periods of pre-assault, assault, post-assault the other aircraft can be used

for their primary missions. It is not economical to task a CH-46 to transport the ground

commander around the battlefield when that aircraft could be used to transport essential

troops and supplies.

Another example is armed escort of transport aircraft to the landing zone (LZ). An

AH-1 could be assigned the mission but this would prevent it from being used in an

anti-mechanized role. Considering there are only four AH-1W in a typical deployed

MEU, where would they be best utilized? Tasking UH-1Ns to escort sorties releases the

Cobras for other critical missions. Assigning utility missions to other assault support

aircraft would result in task overload and a significant loss of flexibility. The Huey

ensures no mission gaps occur within the helo assault support element; therefore, the

UH-1N in the utility mission provides necessary versatility and flexibility that is essential

to the MAGTF. Tasking this mission to the UH-1N allows for efficient use of other

helicopters. However, the question is: Can the UH-1N continue to perform the utility

mission until it is replaced in 2010?

The UH-1N is an "out-of-production-model"; therefore, new UH-1Ns cannot be

purchased. Flight time continues to add up on the existing airframes and with an

attrition of so many aircraft per year due to accidents the use of the remaining aircraft

increases. As an example, MEU deployment requirements on the east coast squadrons

(HMLA 167, 269) are demanding. Frequently between chops, which is the assignment

of personnel and aircraft to deploying HMM squadrons, the squadrons are left with only

two to four aircraft for a month or two until the MEU detachment being relieved returns.

This type of demand has started programs like Aircraft Service Period Adjustment

(ASPA), which in simple terms is an inspection to determine if the aircraft must be sent

for rework at its normal interval. However, it is not the detailed inspection and rework

performed at depot level. If an aircraft passes inspection, the minor discrepancies are

corrected and the aircraft remains in the fleet for another year until its next ASPA

inspection. This is good for fleet and MEU demands but it accelerates airframe fatigue.

Many aircraft have now passed ASPA inspections two and in some cases three times.

Not surprisingly, the aircraft have shown significant airframe fatigue such as engine

deck deterioration and liftbeam cracks. The liftbeam is the main attachment point

between the transmission and the airframe. Airframe fatigue may also cause

transmission-to-driveshaft-misalignment which is possibly linked to two recent fatal

mishaps. This being the case, how is this airframe expected to last another 20 years?

When it was introduced in the 1970's, the "N" had increased capabilities over older

models but with little change in maximum airspeed. Entering the 1990's its

performance has fallen far behind modern helicopter technology and, in respect to

current MAGTF helos, it is the least capable. The UH-1N lacks airspeed compatibility

with other assault platforms. Its maximum rated speed is 130 knots (kts) but at

maximum gross weight the velocity-never-to-exceed (VNE) becomes 110 kts at sea

level and decreases rapidly at higher altitudes. (6,1-4-5) ln contrast, the CH-46 has a

cruise airspeed of 130 kts, CH-53 150 kts, and the AH-1W 130 kts. To capitalize on

surprise from over-the-horizon launch positions, 20 to 30 kts makes a significant

difference. The UH-1N's limitations force the helo assault wave to fly at 90 kts vice a

capability of 130 kts. Speed is a tactical advantage that must not be squandered.

The cabin capacity is rated for 13 passengers, 8 combat troops or 6 litters, a useful

capability. This is based on the standard fuel load that equates to approximately 1.5

hrs. To complete a typical command and control mission, the Huey requires a flight

endurance time of roughly 3 hours. To compensate for the fuel shortfall, an auxiliary

fuel bag (aux bag) was developed and is now standard for most missions. The bag is

installed in the interior aft cabin. The fully loaded weight is 1000 lbs. and takes up two

passenger seats. Although this solves the flight endurance problem, it significantly reduces

the cargo-carrying capacity. The maximum gross weight for the aircraft is 10,500 lbs.

The basic weight is approximately 6800 lbs. With full fuel for three hours (2400 lbs would

be internal, 1000 lbs. in the aux bag), and crew of three (600 lbs), a quick calculation

comes 9800 lbs., leaving only 700 lbs for cargo and passengers. (Table I) With the

command and control radio package weighing 100 lbs, there is room for only three

passengers.

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At a maximum air speed of 110 kts this doesn't provide much capability. Then, too,

calculations for an ordnance load also impose restrictions.

Without a comprehensive upgrade, the UH-1N will become insupportable long before

the 2015 planned retirement date. A utility platform, by nature of its multi-mission

capability, the Huey provides increased efficiency and productivity. These mission tasks

are essential to the success of the MAGTF. Therefore, the Marine Corps has two

options: (1) either conduct a mid-life upgrade of the UH-1N or (2) purchase a new

helicopter. A mid-life upgrade must significantly increase the Huey's capabilities to be

compatible with the existing Marine helicopters. As for a new aircraft, there are several

existing "off-the-shelf" helicopters that could satisfy the combat utility role, e.g., the

UH-60 Black Hawk, the Bell 412, or the Sikorsky S-76.

The objective of Bell Helicopter's UH-1N Mid-Life Upgrade (MLU) program is to

extend the service-life of the UH-1N until VMAO introduction, expand mission

capability, reduce vulnerability, lower life-cycle costs, be affordable, and increase safety.

(5) The MLU would increase power to the main rotor by 25%. This would be

accomplished by installing GFE T400-402 engines (1970 SHP from 1800 SHP);

upgrading the transmission (1593 SHP from 1290 SHP); installing a composite four-

blade, manual-folding, main rotor; and installing a new KAFLEX main driveshaft. The

maximum gross wt. would then be increased from 10,500 lbs. to 11 ,900 lbs. with a

decrease in the empty wt. by 150 lbs. The useful cargo load would thus be 2100 lbs.

for the MLU vice 700 lbs. for the UH-1N. This is calculated for a three-hour mission

and is a significant improvement in capability. The installation of the four-blade rotor

would increase maneuverability and safety, reduce vibrations by 40% and lower