Where Do Crew Chiefs Come From?
What Do They Do?

by Cpl. Thomas J. "TJ" Miller

Let me start with a little back ground information.  November 1965 I received my draft notice to be inducted into the Army.  Knew it was coming so was just waiting for the day.  At the time my brother was in the Army and I had little interest in it.  Was somewhat undecided what I would do.  Crunch time.    Next day after receiving draft notice went down to the post office in Rochester Minnesota where all of the services had there recruiting offices.  Sat down in the hall in front of the empty Air Force recruiters office.  Looked up and across the hall in the door way stood one of the most impressive figures I had even seen.  A Marine Corps recruiter in his modified dress blues.  "Can I help you", he asked.  "No sir, I'm waiting to see the Air Force recruiter" was my response.  "Why would you want to join the Air Force".  I did not have an answer.  "Come on in,  ever considered the Marine Corps?"   So I entered his office.  A million thoughts were racing through my mind.  A part of me was saying "you could never make it".  Didn't believe I was Marine Corps material.  I was about 100 lbs short of the Charles Atlas physique I thought was required.  As I sat down I noticed a model of a UH-34 helicopter on his desk with Marines painted on the side.  I explained my situation and asked what he knew about helicopters.  "That's my primary MOS, helicopter crew chief."  My mind is numb by now.  This guy (S/Sgt. and can not recall his name) was way off the charts COOL.  My next question, "How do you get to be a helicopter crew chief."  I note a slight smile.  "Have I got a deal for you."  4 year enlistment, aviation guarantee.  I was hooked.

I left his office in seventh heaven.  Now I have a goal.  I am going to be a Marine and on top of that a helicopter crew chief.  Rush home and broke the good news to my mother.  "Mom, guess what I just did.  I joined the Marine Corps for 4 years and I'm going to be a helicopter crew chief."  As I noted the color draining from her face she responded, "That's nothing to joke about, that's not funny."  "Mom, I really did, I have to go the Twin Cities tomorrow, get my physical and be sworn in."  "They have a 120 day delay plan and I don't have to leave until the end of March for basic training in San Diego."  At the time I had worked for IBM for 8 months.  I used 119 days of the delay plan,  left IBM with 1 year and 2 days of employment which gave me some very nice benefits.

March 29, 1966 I stepped off the bus at MCRD and stepped onto those yellow footprints. The thought crossed my mind as to if I really wanted to be a helicopter crew chief all that bad.  I had one focus, "I am as good as that next guy, I can do this."  I do not recall having a single thought of being a helicopter crew chief in boot camp.  Strictly a survival mode and survive the day.

After basic, a couple of weeks of mess duty at Camp Pendleton and ITR I was on my way to NAS Memphis  for basic aviation school.  As I get to know the ropes I find out that "Aviation Guarantee" guarantees me 1 week of basic aviation fundamentals and then I will be placed in a capacity of the Marine Corps choosing.  Hmmmm....   Guess I should have read the fine print.  End up getting assigned to barracks and grounds detail and work in a woodworking shop.  Several months pass and I'm still on my detail.  Getting sick of Memphis so apply for AC/GCA school.  Failed my depth perception test.  Hmmmmm....   Apply for ordinance school in Jacksonville, FL.  I'll be a bomb juggler.  School is filled.  About this time a Gunny Sgt. at my work place asked me what I was supposed to be doing.  Was I waiting for a school?  Yes, Gunny, I'm waiting to my basic zero week school.  "How long have you been here".  3 or 4 months.  "Why aren't you in school."  Beats me Gunny, guess my name just hasn't come up.  (Note:  During my time frame at the wood shop I built that Gunny a gun rack.)  "Miller, we have to get you in school."  The next week I started zero week.  In our conversation the Gunny asked what kind of school did I want.  "Helos Gunny, want to be a crew chief."  "I'll see what I can do."  Next came 4 weeks of mechanical fundamentals (mech fund).  Did well, good grades.  Was called in the Gunny's office during mech fund and he explained Jet school was full but he was going to assign me to Recip school  (Reciprocating Engine).  In that conversation found out the Gunny was in charge of assigning Marines to various schools. Finished top in my class of Marines and a sailor beat me out for class honor man.  Gunny assigned me to helo class.  Was Honor man out of helo class.  Our classes were about 50/50 sailor/Marine ratio.  I will always remember my first day in Helo class.  Instructor said,  "It is a proven scientific fact that a rotating airfoil  can not produce lift, thus it is impossible for a helicopter to fly."  Never grasped that information so basically ignored it.

Spring of 1967 and headed for the fleet at LTA in Santa Ana, CA.  Assigned to a H&MS (Headquarters and Maintenance) shop.  They rebuilt components.  After a couple of weeks, hear there is a squadron forming to go to Vietnam, HMM-364.  Seem to remember I put my name on a clip board and I was #6 on the list.  Few days later I'm transferred to HMM-364.  Very few personnel, no aircraft but somebody established a coffee mess so we had a place to gather.  In a fairly short time frame things began to fall in place and we started receiving aircraft.  Remember the first time I got to go inside a CH-46.  Spent most of the day crawling over it, top to bottom.  Holy, moly, I'm going to be a crew chief on one of these.  I wasn't ever sure what that entailed.  Believe the first work I ever did on a CH-46 was wipe it down with a half mixture of JP (jet fuel) and hydraulic oil.  Stood back and admired my work.  Had a nice shine.  I had always seemed to have a wrench in my hand as a kid but as I examined the intricacies of this monster I was awestruck at its complexities.  It would take me 2 life-times to learn all about it.

Those early days tend to be a blur as I reflect back some 40 years.   Remember Sgt. Bob Lewis was our NATOPS instructor and we spent quite a bit of time in the class room and following him around on the aircraft learning nomenclature and terminology.   Study at night and work during the day.  Seems all those thousands, so it seemed, pieces fit together in some sort of order and all played an important part of the integrity of the aircraft.  In time, it was no longer intimidating, and familiarity lead to confidence.

The one person most instrumental in my quest to become a crew chief was SSgt. Jack Hildebran, my section leader.  Big, barrel chest, deep gravely voice and years of experience on the UH- 34.  Most of our staff NCOs had rotary experience but most were new to the 46 because it had not been in the fleet that long.  So, we were all in the learning mode.  Remember the day SSgt. Hildebran said "Miller, go up to Flight Equipment and check out your flight gear".  Wow, what a rush.  Helmet, flight suit, gloves and that highest of all status symbols, that leather flight jacket.  SSgt. Hildebran was an invaluable mentor.  Firm, no short-cut, attention to detail guy.

And then, that butterfly feeling in your stomach as you lift off for the first time in a CH-46.  It seemed that in a heartbeat my syllabus is completed and Sgt. Lewis is flying with me on my crew chief check ride.   Sgt. Lewis sharing some complimentary words on shut down and mentioned I was now a NATOPS qualified CH-46 crew chief.  That really didn't sink in until I lift off with my pilots on my solo as a crew chief.  Seems most of the thrill was gone by then and  terrified as to what I would do if the pilot asked me a question or something went wrong.

In roughly 15 months from the day I stepped on those yellow foot prints at MCRD  I'm a United States Marine CH-46 helicopter crew chief, responsible for a million and a half dollar aircraft  in a squadron heading for a place called Vietnam.  Does it get any better than that??  June of 1967 I celebrated my 21st birthday.

Late summer, early fall 1967 all CH-46s are grounded.  Some aircraft had suffered catastrophic aft pylon failures , some with deadly results.  HMM-364 is tasked with modifying 32 aircraft.  The modification entailed gutting the aft section of the aircraft of engines, transmission mix box,  rotor head and rotor blades and all related components there in.  The structure is beefed up and aircraft is reassembled.  Believe the modification was at least a couple of hundred man-hours per aircraft.  In short order seemed everyone was an aircraft mechanic.  It pushed the learning curve into warp speed but later would prove to be invaluable in experience gained.  What could be better than tearing an aircraft down to the bear bones and rebuild it from the standpoint of a crew chief, the aircraft mechanic.  Deployment date had been set for Nov. 10, the Marine Corps birthday.  I can proudly state,  HMM-364 pulled it off and all 32 aircraft were aboard the LPH Valley Forge headed West out of Long Beach, CA on Nov. 10th 1967.  That was truly a defining moment for our squadron.  We were now one,  HMM-364, the Purple Foxes.

November 29, 1967 off the coast of South Vietnam near Phu Bai:  This is the real deal.  Our aircraft are loaded with squadron gear and we launch for Phu Bai.  Within minutes we are on foreign soil.  No idea what to expect.  We had no armaments.  Hell of a way to go into combat.  Things were  secure and no danger present actually.  Somewhere I must of missed that in our brief.  After I saw a couple of our advance party people I felt much better.  They were waving and smiling and running around unarmed so I figured things were pretty secure.  By the end of the day most squadron equipment was on dry land.

Upon our arrival at Phu Bai it took mere minutes to realize it didn't seem there was any particular area for us.  We ended up on the north west corner near the runway and parked our aircraft on the grass.  Nearby we lived in tents and had pallets for a floor.  (Pallets offered a great place for rats, huge rats, to hangout also.)  Phu Bai rats were in the size range of small beavers.  Rude, undisciplined buggers also.  Seemed to wander around wherever they  pleased.  Down right arrogant.

Within in a few days we were starting to fly missions and getting a feel for the area.  Seems about this time the sky clouded up and it started to rain.  Our grassy area turn into a sea of mud.  Pilots tried to taxi aircraft and only ended up collapsing nose struts.  Finally, upon landing we would hover and touch down.  That is where the aircraft stayed until you launched again.  We would pull into a hover and air taxi to the runway and launch from there.  Only one problem.  Rotor wash.  The turbulent air was always causing problems.  Tent flaps blown open and anything not nailed down would be a blown about mess.  Personnel tents were blown over, and personal effects tossed about.  Once a bird turned up, everyone in the flight line tent would lay on any lose paperwork or it would fly about and end up in the mud somewhere.  Cold, wet, muddy, miserable.

This situation added extra burdens for everyone.  Cherry pickers, NC5s, hydraulic mules and other types of heavy equipment needed next to aircraft,  were mired in the mud.  It may take an hour or 2 just to get equipment to the aircraft.  Actually spirits remained high.  In most cases we would make some sort of game or joke about the situation and try to find creative ideas on how to go about business.

Believe it was around New Years when we were moved to our new area.  Thought we had died and went to heaven.  Steel Marston matting for our aircraft to park on and a cement floor and a roof that didn't leak over our heads.  Wasn't a Holiday Inn but you could of fooled me.  By now we were falling into a general type of routine and things seemed to be tolerable.

Dec '67, early Jan '68 seemed to be fairly quiet and flew a lot of routine supply missions.  Am beginning to think this is pretty boring.  Our squadron flew quite a few hours which started to add weight to the work load.  Things were soon to take on a whole new dimension as the '68 TET offensive was about to begin.  Khe Sanh was soon to become an all too familiar place.

As a crew chief my responsibility was to maintain my aircraft and keep it in a "up" (ready to fly) status.  Just the complexity of a helicopter lends itself to a lot of maintenance.  Seems I remember something to the effect of 10 hours of maintenance to 1 flight hour.  That maybe a stateside numbers ratio.  OK, lets do some math.  I launch at 0700 and return to base at 1600 having logged 4 hours total flight time.  My pilot gives me a thumbs up and comments, "pretty good aircraft".  No "bitches" on the yellow sheet.  (Note:  Yellow sheet is a log type form that the crew chiefs signs off that aircraft is ready for flight.  He will list any discrepancies the aircraft may have that are not related to flight safety.   Pilot is assigned to A/C.  Signs yellow sheet to accept the A/C for flight.  When pilot returns he notes days activities and any "bitches" he may have with A/C operation, or anything else he may have on his mind and deems the A/C "up" or "down".  A crew chiefs goal is to have the "up" arrow circled on the yellow sheet always.  At times this may take some salesmanship skills on his part.  Pilots love to come out to the flight line and sign for an A/C with the last 10 yellow sheets "clean" and "Great A/C and crew" also noted by the last few pilots.  "Dirty" yellow sheets, with lots of "bitches", tend to make good pilots wary, and tired pilots grumpy.  A good, tired pilot can become wary grumpy.  Crew chiefs hate grumpy pilots.  Grumpy pilots at times seem to hate everybody.  A crew chiefs goal, clean yellow sheets, with the "up" arrow circled.   Back to the math question.  10 to 1, maintenance vs flight hours.  If I flew 4 hours today that means on the maintenance side I'm looking at 40 man-hours of maintenance and they are scheduling me to launch at 0'dark thirty tomorrow morning.  Hmmmmm....  Better get cracking.

Each crew chief is assigned to a particular bird and that bird is his baby.  Only another crew chief fully understands the love you hold for that big, beautiful green machine.  My bird was the best maintained, most reliable, most powerful, could fly longer, carry more troops, accomplish more missions etc., than another bird in the squadron.  Every crew chief felt that way about their bird.  Mess with my "sweetheart" and you are messing with me.

Soooooo... according to my math there is 40 man-hours of maintenance to be done before tomorrow mornings launch.  My aircraft is my responsibility but there is also lots of support people standing by.  There are tin benders (metal smith's) to repair the bullet holes.   Bubble chasers (hydraulics men) to plug up the hydraulic leaks from the bullet holes.  Tweets (aviation electricians)  to tape up sparking wires frayed and broken from bullets.  Plus a few other specialists who may pitch in.  At any one time there maybe several different shops working on one aircraft.  The crew chief oversees the work and is responsible to ensure everything is up to flight safety standards.  Depending on the level of work performed QC (Quality Control) will probably inspect the completed work and sign it off.

In the course of any aircraft work performed many sets of eyes look it over and may have several people "signing off" in some shape or form that all required procedures were followed in the work.  (Proper torque, safety wire, proper operation of component,  proper adjustment,  etc. etc. etc.  Safety, safety, safety.)  You may only get one chance to screw it up.  One screw up, can end many promising careers in a heartbeat.  All of my screw ups were at some lesser level than the "big screw up".  Each is allowed "one big one".  Once you use it (the big one) nothing else matters, those aboard are now fondly remembered by there fellow squadron mates.  No incentive needed here, the crew chief flies every time his bird does.

One single military aircraft has a paper trail a mile long.  Many components are serialized and also have service hour limits.  These components have there own log book and will follow that component for its service life.  The maintenance office is charged with keeping records in order.  The crew chief is notified of components that are approaching "high time".  He will have to schedule component swaps when ever it can be fitted   into the schedule.  The replacement component also has to be available.  In the absence of a readily available "high time" replacement component one may have to resort to "Cannibalization".  Yes, if we must, we eat our own.

Cannibalization:  Aircraft "A" needs a rotor head because of "high time" or battle damage.   Aircraft "B" is down for a transmission change and has a rotor head with only 200 hours on it.  600 hours is the service limit.  The "cannibals" from aircraft "A" descend upon aircraft "B" and remove the rotor head and replace the "high time rotor head on "A".  Now "A" can be put back in the up status.  Total swap-out time,  6-8 hours plus blade tracking and retorque and test hops.  But now we have aircraft "B" that will get a replacement rotor when one is available and many extra hours will be charged against that aircraft because of the "cannibalization" of the rotor head.  Bottom line, more work, but "A" is up and fulfilling a mission assignment.

Parts availability:  The number crunchers and bean counters have a pretty good idea as to the components service life, replacement numbers and failure rates.  In a combat zone you can throw those numbers out the window.  They had better order lots of everything and hope they get some of it.  Parts in normal service there whole service life would be swapped out when flight hours warrant change.  Under combat conditions, premature parts replacement generally happens due to the accuracy of the bad guys hitting said component.  Thus, the cannibilization technique is used to supply the flight line with useable parts.

It seemed at times it was a full time job of the crew chiefs just to hold the cannibals at bay.  Even before you touch down on final for the day a good crew chief has formulated a plan he will explain to the line chief as to why his "downed" aircraft should NOT be cannibalized.  Through his sales skills, if he can convince his pilot, who maybe ready to "down" the aircraft, that the "bitch" is minor, the crew chief will be formulating a plan as to how he can cannibalize  that much needed part  to fix the "bitch" and thus keep his aircraft "up" and also maintain that coveted "clean yellow sheet".  This is somewhat of the dominoe effect you may have read about.  The dominoe affect can apply to may things in life as it can apply to the helicopter crew chief.

I am not sure if there was ever a "typical" day in the life of a crew chief.  Generally he stumbled out to his aircraft in the dark, with the aid of a flashlight, and would preflight his bird.  (A good crew chief always had a few extra batteries stashed in a strategic location.)  20-30 minute pre flight.  Go to the line shack and sign off the "yellow sheet" and find out who his pilots are and what type of mission they will be flying.  Gunners are bringing out the guns and the pilots go about there pre flights.  The crew chief follows along and answers any questions the pilots may have.  "How bad is this oil leak Miller."  "Half a rag or so, sir".  (Note: 1 rag oil leak = leak that can be absorbed with 1 rag after completing a days worth of flying.  Totally honest here:  a crew chief "may" fudge a bit on rag requirements to absorb leak.  See above comments: this is done not to deceive but maintain "up" status and "clean yellow sheets". )

With all players present the pilot calls out "Ready Ape."  "Ready Ape, sir."  The APP, ape, is the auxiliary power plant and provides electric power and hydraulic pressure to the aircraft systems for start up.  The APP has a hydraulic starter and during APP start up you will find the crew chief pumping his brains out trying to add a bit of hydraulic pressure to ensure the APP fires up.  If it doesn't,  he will be pumping the handle for the APP hydraulic system approximately 200 strokes as the pilots sit unimpressed in the cockpit.  Not a good way to start the day.  The old saying "Poop Occurs" applies here and sometimes it did.

APP on line, crew chief out front  and gives the pilot a thumbs up on #1 engine,  cross to other side and thumbs up on #2 engine.  Engines on line, systems look OK.  All clear to engage rotors.  Rotor brake off, rotors turning and brought up to speed.  Miscellaneous system checks,  pilots establish communication with other aircraft in theie flight and start to taxi to active runway.  All clear from tower and we are on our way.  Lord only knows the events of the day and when or if we will taxi back into our revetments.

Flight operations have the crew chief serving in many different capacities.  External loads he'll be on his belly, looking through the hell hole, directing the pilots to the hook-up with the external load.  He'll maintain that position until the cargo is delivered to the LZ.  He is the pilots eyes in these types of operations.  Internal cargo loads tended to be a bitch.  Gear needs to be tied down and secured.  Try unloading rolls of barbed wire and steel fence posts in a hot LZ.  (Actual experience here..)  (Bean counters said they were all out of cargo nets.)  Troop lifts:  ensures passengers are seated, ramp clear, not to many troops aboard.  (Note: crew chief has to make guestimations as to weight of whatever is being hauled.  Many factors play into a 46's lifting capacity on any given day.)  Clears pilot on landing in LZ and ensures troops disembark and clear of aircraft before lifting off again.  Medevacs:  clears pilot into LZ watching for hazards upon landing, if we can land.  Once aboard, assist "Docs" if present or assist medevacs as best you can in the absence of "Docs".  (Many times wished I had some sort of medical training.  Old Boy Scout first aid was put to use at times.  Primitive, not pretty, but hopefully had some effect for efforts extended.)  Emergency Recon Extracts.  Generally total chaos.  Recon team in contact with enemy, may have casualties.  Say quick prayer and head on in.  Always knew how many men on the team.  My greatest fear was we would leave someone out there.  Never happened.  Always took head count twice before calling "clear to launch".   Hoist extractions:  Cable run down belly of aircraft and controlled by crew chief as he directed pilots.  Pilots blind to activities under belly of aircraft.  Had big advantage here for awhile.  Had hoist mounted on platform and arm extended out side door of aircraft.  500% over hoisting through the belly.  Pilot could also see some of the activity.  In some of those incidents needed a few extra hands.  Would have loved voice activated mikes.  All in all, once you launched in the morning the days activities had a tendency to have a life all there own.  Do what ya gotta do.  Get the job done, support our grunt brothers who were fighting the war.

Once mission assignments satisfied we would return to base.    If pilot deemed aircraft "up" you would post flight and check for anything out of the ordinary.  Now, the second part of our work day would begin. Check thoroughly for battle damage if you had received fire.  Easy to miss  hole in big aircraft.  One could easily spend an hour or two putting your bird back in order after a days worth of flying.  Always cleaning "donkey dick" the engine air inlet filter.  Things to grease, oil leaks to clean up, cabin area filthy, clean windshield etc., etc., etc.  There were weekly, bi-weekly, month checks for various systems.  Maybe some of those checks applied, if so, you would complete them.  If your aircraft was up and ready to go you would probably lend a hand to one of the other crew chiefs in your section with some of his tasks.  I don't think there was ever a time there wasn't something to do.

Many times an aircraft would come back with serious problems.  If parts were available, work continued well into the night and maybe have a test pilot come out early and fly a required test hop so aircraft could be put back into the up status.  At times  a test pilot and crew chief would fly a early morning test hop, come back to base and if A/C "up" pick up the rest of the crew and head out on daily mission assignments.  Remember some of our test pilots hanging around most of the night so test could be done and aircraft would be ready the next day.  Rotor blade tracking had to be done at night and at times was very time consuming.  Lift off,  get blade tracking readings, land, shut down make adjustments.  This procedure was repeated until the blades were in proper track.   Could be 6, 7 or 8 launches to get it right.  Attention to detail paid off.  Well tracked bird was smoooooth.  Pilots loved smoooooth birds.  No, "slight one per" on yellow sheet.  Invariably, a "slight one per" would get you a "needs blade track" within the next two pilots, guaranteed.  "Just what I need."  More work.  Sometimes you would get lucky.  Next hop after "slight one per" bitch on yellow sheet you would take a round in a rotor blade.  Replace blade, track and be back up.  "Don't worry about that one per bitch, sir.  Took a round in that blade and it has been replaced."  Was always amazed that the blade that caused the "one per" was the blade that was always hit and had to be replaced.  Seeds planted from past yellow sheets were a real nemesis.  As mentioned earlier, a wary pilot wonders as to  the general health of that aircraft.  Can lend itself too a long day.

Long days??  Remember at times nearly numb from fatigue.  Believe some of our pilots may have wondered  at our demeanor and our competence.  Most of the time we were pretty giddy.  Walked around in a "fog".  Real space cadets.  At times am sure we looked like a pretty motley crew.  Couple of days with no sleep.  Couple days of beard.  Breathe that could stop a train.  (Pilot asked me one day to not breathe in the cockpit.)  Go down to take a shower in the middle of the night and find no water.  Flight suits that should have been "surveyed" last month.  Actually, there was a time the crew chiefs were holding a contest as to who had the goriest flight suit.  Someone stenciled "No Smoking with in 50 feet" on the back of mine.  None were to be had in Flight Equipment.  Seem to remember I wore a tan flight suit for the first couple of months in country because that was all there was to be had.  (Originally, it was tan in color.)   Believe I logged 14.8  (my "Longest Day") hours in one days worth of flying.  When we finally shut down for the day I was on my 3rd set of pilots.  Probably could have been relieved by another crew chief but when my bird lifted off,  I was aboard.  We all felt that way.

The few, the proud??  Not sure where our competitiveness came  from.  Crew chiefs definitely do have a competitive spirit.  (My bird is better than your bird syndrome??)  The goal was always an "up" aircraft.  One may have had to beg, borrow or steal but the final goal was always the same.  An "up" aircraft.  A squadron is divided into 4 sections with each section having 6 aircraft.  Crew chiefs are not only competing with each other but there is a certain camaraderie within each section.  These were the guys you were closest with.  You worked within your section first and then help guys in the other sections if necessary.  Seem to remember, though no official records were kept, everyone knew which section was flying the most hours.  Think I can honestly say my section was generally #1 or #2 in flight hours.  Not sure why, but if people were shuffled around,  the replacements always seemed to fit in and pulled their share of the load.

I could go on and on.  Looking back all of those years sometimes wonder what we were running on.  Felt like empty but kept going.  Least we could do for our grunt brothers whose lives were dependent on us.  Just came with the territory.  Am so proud of the "Purple Foxes" and those I served with.  Remarkable bunch.  What a privilege and honor to be a part of their history.

Semper Fi,


Cpl. Thomas J. Miller's History Index

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