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

 

maintenance costs.  The reduction in vibrations would reduce pilot fatigue and increase

 

the life of critical components.  The cruise airspeed would increase to 130 kts. with a

 

VNE of 140 kts. (5)  This speed improvement would enable the Huey to keep up with

 

the assault helicopter wave allowing utilization of the CH-46's full airspeed potential.

 

     Fuel capacity is increased by 113 gals., giving an endurance of 3.0 hrs. and a

 

combat radius of 170 nm.  An improved auxiliary fuel system designed by the USAF

 

can also be incorporated for specified missions, further increasing the Huey's range and

 

endurance.  New energy attenuating crew and passenger seats will increase survivability

 

in a crash.  Ballistic improvements will be minor but include improved pilot seat armor

 

and main rotor blades that will tolerate a 14.5mm hit.  In addition, the airframe will be

 

strengthened and the liftbeams replaced. (5)

 

     The second option is to replace the UH-1N with a new-type helicopter.  The Vietnam

 

experience changed the Army's requirements for the next generation utility helicopter.

 

High performance, survivability, reliabilty, availability, and maintainability became the

 

goal.  The Huey had performed remarkably but it had many shortcomings.  In 1974

 

Sikorsky was awarded the Army contract to build the H-60A Black Hawk and the first

 

production helo was delivered in 1978.

 

     The Black Hawk is now in all five branches of the US military service.  The USMC

 

flies the VH-60 at HMX-1 for Presidential support.  Besides the missions assigned to

 

USMC utility role, the Army also employs the Black Hawk for electronic warfare, anti-

 

tank warfare and mine-barrier operations, thus proving its versatility.  The Black Hawk

 

has undergone several variations to accommodate different missions within the services.

 

Of particular interest is the Navy's SH-60B Sea Hawk because of its shipboard

 

compatibility which is necessary for all USMC helicopters.  The Sea Hawk is used as a

 

light airborne multi-purpose system (LAMPS) Mark III with primary missions of anti-

 

submarine warfare (ASW), and ship surveillance and targeting (ASST) with secondary

 

missions of SAR and logistics support.  Although the H-60 is larger than the UH-1 its

 

footprint would have minimal effect on LHAs and LHDs.

 

     The Black Hawk variation designed for the USMC is the H-60L.  It is a single-rotor,

 

twin-engine helo large enough to carry 15 troops plus a crew of 3 for normal combat

 

operations.  Up to 20 troops could be carried in a high density configuration.  Empty

 

weight is 13,027 lbs., mission gross weight is 16,600 lbs. (crew and full fuel) with a

 

maximum gross weight of 22,000 lbs.  This allows for 5,400 lbs of cargo load.  The

 

max load that can be carried on the external sling is 8000 lbs., thus lifting a fully loaded

 

HMMWV with its crew. (1:18)

 

     The Black Hawk's endurance is admirable.  With 12 troops and the remaining cargo

 

capacity used for fuel it has a combat radius range of 225 nm.  With the External Stores

 

Support System (ESSS) an additional 2500 lbs. of fuel can be carried giving a total

 

flight of six hours and extending the combat radius to 400 nm. (1:24)  This is a

 

significant advantage over the MLU in the comand and control role.

 

     Cruise airspeed for the H-60L is 145 kts with a VNE of 165 kts.  This speed

 

advantage over the UH-1N will not only allow the utility helo to stay up with the assault

 

helo wave but also will give it a sprint advantage to reconnoiter the landing zone prior to

 

the transports landing.

 

     Another impressive feature of the Black Hawk is its ballistic tolerance.  There are no

 

areas vulnerable to a 7.62mm round.  This is accomplished through strategic placement

 

of redundant systems and protection of all critical components.  No matter where a

 

bullet penetrates the flight controls, it is impossible to cause separation.  The entire

 

four-blade main rotor is also ballistically tolerant.  The hub is invulnerable to 12.7mm

 

hits while the blades will not fail after a single 23mm high explosive incendiary (HEI)

 

round in the spar. (1:21)  The pilot seats are armored and the transmission gear box is

 

designed to operate for 30 minutes without any oil.  The Black Hawk incorporates a

 

suction fuel system on the engines in contrast to the UH-1N which has fuel pumps that

 

feed the fuel into the engine.  If a fuel cell is penetrated by a bullet it will not leak; air

 

would be ingested but fuel would not be sprayed as in a pressure system.  Fuel lines are

 

flexible, self-sealing, and incorporate self-sealing break-away valves.  The fuel tanks are

 

self-sealing to 12.7mm ballistic damage. (1:14)

 

 

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     As shown in the Table II, the Black Hawk provides a significant increase in capability

 

but at a price.   There are some additional costs such as maintenance support

 

equipment, parts, and mechanic and aircrew training that will affect the decision also.

 

Currently the HMLA squadrons have the UH-1N and the AH-1W, both Bell products.

 

This allows the use of many common systems.  By electing the MLU option vice buying

 

the H-60 the support structure remains in place.  Of the 195 pieces of support

 

equipment required for the MLU, 121 are common to the UH-1N.  Likewise, many parts

 

will be common and the distribution system the same. (5)

 

     Mechanic training will only need upgrading with the MLU instead of the complete

 

retraining for a new type aircraft.  Since the HMLA squadrons have two Bell helicopters,

 

many mechanics are qualified on both aircraft because of common systems.  On the

 

other hand, buying a new aircraft might require additional maintenance personnel.  Pilot

 

training for a new type aircraft would also be significant.  Pilots would have to be

 

retrained to become flight qualified and then continue training until combat qualified.

 

This transition would be at a high cost for schools, fuel, parts and maintenance

 

manhours just to combat qualify the aircrews.  Is the increased capability of the Black

 

Hawk over the UH-1N MLU worth the cost?

 

     The tiltrotor concept will bring a significant leap in technology and capability but there

 

is no guarantee when it will arrive.  The V-22 which is to replace the CH-46 must be

 

funded and fully fielded before the VMAO can become a competing priority with other

 

projects.  Is 2015 a good guess or just a shot in the dark?  There is one remaining

 

question:  When can these options be fully fielded?  The current POM cycle is for 1996.

 

If Sikorsky was awarded the contract for POM 1996