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Hi

Can anyone please tell me what is involved in a C-Check and a D-Check and at what intervals are they done?

Are there any more checks like a E-check or an A-Check.

Also on a flight last week whilst at the gate an engineer drove up to the A321 opened up the engine side cover and put a can of something in each of the engines.

What would he have put in the engine?

Thanks in advance.

Quoting Captainsimon (Thread starter): Also on a flight last week whilst at the gate an engineer drove up to the A321 opened up the engine side cover and put a can of something in each of the engines. What would he have put in the engine?

Oil, perhaps? Jet engines consume their oil, they don't have a closed lubrication system like a piston engine.

Quoting Captainsimon (Thread starter): opened up the engine side cover and put a can of something in each of the engines.

Redex?   

Not certain, but I have heard of aircraft being scrapped/sold because of the cost of a D-check. If there's a level above that, it must be above the equivalent of what the Navy do to carrier-based aircraft. And I can't see an airline sucking down a cost like that so I don't believe it exists.

I believe that A-Checks are the day-to-day stuff (tyre kicking if you like) and that B-Checks are every few months.

I equate this to the following car analogy;

A-Check: Fluid levels, (oil, coolant) obvious leaks. Maybe tyres.
B-Check: Oil leaks, smokiness, brake pads and discs, light bulbs (that last one is probably on the aircraft A-Check)
C-Check: Steering rack, hoses, filters, aircon if fitted.
D-Check: Cam belt/chain, structural integrity and welds, paintwork, suspension, CV boots, fuel system, airbags, etc, etc, etc...

It's not quite analogous since a car will happily bimble along with faults that a plane would not, but I think that's the idea.

Sir, you may find this of interest;

http://www.aerosphere.com/Magazine/AERONAUTICS/aeronautics.shtml

Quote: However, the best single tool in aircraft maintenance is said to be the human element —sharp eyes and alert minds.

This has been discussed here before. Perform a search.

Basically, maintenance checks and intervals are set by the operator in conjunction with the manufacturer and the regulatory body.

We, for example, have:

Arrival service checks, daily
Periodic service checks, approximately weekly

After that, our requirements diverge by fleet. Some aircraft get A checks, interval determined by aircraft type. Some get Phase checks and some get higher (numerically, PS2, PS3, etc) Periodic Service Checks.

After that, they all kind of converge into 'C' checks. 'C' checks, for us, also incorporate part of the 'D' check package. This eliminates the need for a 'D' check, but keeps the aircraft out of service for a longer time at 'C' check.

In short, the answer to your question is, it depends on the aircraft, the operator and the government.

Quoting Captainsimon (Thread starter): Also on a flight last week whilst at the gate an engineer drove up to the A321 opened up the engine side cover and put a can of something in each of the engines.

Oil. Though modern jet engine do NOT consume their oil, normally, you will have to top them up occasionally, just like you car. Oil consumption, on newer engines, especially ETOPS certified engines, is measured in fractions of a quart per hour.

We perform the following on our fleet.


Daily Check-Performed every day.

Service Check-Performed every 3 days.

A Check-performed every 250 hrs.

C check-performed every 18 months.

D Check-performed every 5 yrs.

This is just a basic summary but their is allot more work that is scheduled along with these checks also we have just completed the transition to MSG3 maint program on the fleet.   

Also, many programs now fold the D-checks into C-checks. So whe you do a C check you also perform parts of a D check. That way you have no D checks and thus no very prolonged time out of service.

Quoting Captainsimon (Thread starter): Also on a flight last week whilst at the gate an engineer drove up to the A321 opened up the engine side cover and put a can of something in each of the engines. What would he have put in the engine

He was topping up the Engine Oil.

About the checks.It depends on the company & Aircraft type.
Check C is a longer check approx 4-5 days depending on Man-hrs utilised.
The biggest being check D,takes 2-3 months.
regds
MEL

The names of the checks can be different for different operators so it can be confusing. At DL we do transit checks at every overnight MTC station. I think a plane needs one at least every three days. Next up the scale is a Layover check. I don't know the frequency, maybe weekly. Next is a service check which I think is on a 250 flight hour interval. After that some get Letter check(MD88) others go to PSV checks which are also hour driven and occur at about 18 month intervals. Some fleets; 738, and 777 have used the PSV system to completely replace the overhaul/ D-check. Our 767 and MD-88/90 fleet still get overahaul at the end of the PSV/Letter check cycle which I think take five years.

Yes, the mechanic was adding oil to the engines. Some engine types use a lot of oil. The CFM56 can use 4-6 quarts in a cross country fllight.

As others have said search this forum for this topic. This question is very common and there are some very detailed answers in the archives.

We have:

Preflight
Daily
Weekly
A Checks (overnight)
C Checks (3 or 4 days up to 2 months)

We have no D checks in our programme. I assume this to be due to it being covered in some of the longer C checks that we carry out.

A couple of operators that we do 3rd party for class their checks as

LMV (Light Maintenance Visit) - LMV1 - LMV4
HMV (Heavy Maintenance Visit) - HMV1 - HMV4 (there may be more levels I do not know, these are what I have seen).

Quoting DALMD88 (Reply 8): At DL we do transit checks at every overnight MTC station.

Shouldn't transit check be the basic check covering a transitting Aircraft.
regds
MEL

Quoting HAWK21M (Reply 10):

I know that would make sense, but that is what our program calls the most basic check. I believe we are required to do one if a plane sits at a MTC base longer than six hours. So every overnight aircraft gets one. It is a real simple check; tires, brakes, fluids, oxygen, clean windsheild, walkaround, and a walk through the cabin. You don't even check emergancy equipment in the cabin. I usually do check for it to all be there and for required safety seals.

Quoting DALMD88 (Reply 11): I know that would make sense, but that is what our program calls the most basic check. I believe we are required to do one if a plane sits at a MTC base longer than six hours

Interesting.
What is your Transitting Aircraft check called.
regds
MEL

Quoting KELPkid (Reply 1): Jet engines consume their oil, they don't have a closed lubrication system like a piston engine

I think you'll find that commercial engines are closed systems. If not, the oil tanks would be gargantuan.
The only open system I can think of was the Bristol Orpheus, which was designed as a target drone engine and therefore had no life and a short flight time. Making it a open system reduced cost and complexity of a scavenge system.
I guess there are several other examples in a similar light.

Quoting HAWK21M (Reply 12): What is your Transitting Aircraft check called

For a nonETOPS aircraft they used to called through flights. There isn't any actual through flight check in our paperwork. A mechanic just goes out and meets the plane to take care of any issues the crew has. I personally don't do many of these, due to my work hours. Maybe once every couple of weeks I get assigned one of our redeye inbounds near the end of our shift.

Quoting DALMD88 (Reply 14): What is your Transitting Aircraft check called

I'd swear, back when I was a widget, these were called Transit Checks. But then again, I was doing a lot of contract work on JFK at the time along with my work on LGA. Might have some operators mixed up.

Quoting DALMD88 (Reply 14): For a nonETOPS aircraft they used to called through flights

There would be an official term.What does the Document signed read.

Quoting Fr8mech (Reply 15): I'd swear, back when I was a widget, these were called Transit Checks

Out here its called Transit check/Preflight check.
regds
MEL

Quoting HAWK21M (Reply 16): Quoting Fr8mech (Reply 15): I'd swear, back when I was a widget, these were called Transit Checks Out here its called Transit check/Preflight check.

Nearly all operators of short haul aircraft in Europe do not have mechanics meeting transit aircraft. The pilots do the walkround and the refuelling. If the pilots need help they call someone and a mechanic shows up.
On ETOPS aircraft a transit check by a mechanic is required, and we do them on B747 as well.
The first required inspection on the shorthaul fleet is a Daily check, which is carried out every nightstop, and at least every two days if the aircraft doesn't nightstop.

Quoting TristarSteve (Reply 17): If the pilots need help they call someone and a mechanic shows up.

POOF! Out of thin air! 

Quoting TristarSteve (Reply 17): Nearly all operators of short haul aircraft in Europe do not have mechanics meeting transit aircraft. The pilots do the walkround and the refuelling. If the pilots need help they call someone and a mechanic shows up.

Out here,Pilots only certify Transit checks for Weather related diverted Aircraft,due non presence of Licenced AME,provided there is no Snag present.Although CAR-145 permits Pilots certifying Transit checks of certain category Aircraft,but most Airlines have not gone along with it.

regds
MEL

PART-145 APPROVAL IS NOT REQUIRED FOR A PRE FLIGHT CHECK, thus a licenesed engineer need not sign. That is a factual statement ! Flight crew are not allowed to sign an ETOPS check, however they can sign a pre-flight check, so , why spend money basing an engineer down route when you dont need one?

Quoting A/c train (Reply 20): PART-145 APPROVAL IS NOT REQUIRED FOR A PRE FLIGHT CHECK, thus a licenesed engineer need not sign

I was talking about Pilots  .True out here Approval holder holding BAMEL can be approved for clearing Transit checks.
regds
MEL

Quoting Starlionblue (Reply 18): Quoting TristarSteve (Reply 17): If the pilots need help they call someone and a mechanic shows up. POOF! Out of thin air!

If you are lucky!
We have company engineers at some stations, contract engineers on call at some, and at stations where there is less than one flight a day, we usually have no-one. The engineer has to be flown out from base!
10 years ago there was an engineer on every transit. Now when I go on board one of our aircraft, usually to pick up some English papers, or get a breakfast, the crew are surprised to see me.

Quoting HAWK21M (Reply 16): There would be an official term.What does the Document signed read

There is no document. We don't have check for through flights. A mechanic is assigned to each inbound flight in case one is needed. If there is no inbound 'I need a mechanic' call you don't have to meet the flight. If your not busy doing another task you do go out and walk around it to try and catch anything the crew might find on a walk around. If you do anything like oils, it goes in the book, otherwise nothing goes on paper.

Now an ETOPS flight would be different. We don't get them at my station, so I'm not familair with the Predeparture Check.

Quoting DALMD88 (Reply 23): If you do anything like oils, it goes in the book, otherwise nothing goes on paper.

What about Refuelling Trch log & Pilots Acceptance record.What is the Paper proof that the Aircraft was cleared for flight,in case of any Investgation.
Where is the Accountability.
regds
MEL

Quoting HAWK21M (Reply 24):

At the end of any work on the plane a qualified mechanic signs the airworthines release. That release is valid until another entry is made in the book. So as an example the 600am LAX inbound comes in. I'm assigned to that flight. I meet the flight at the gate. While the plane is unloading I do a quick walk around. Tires and brakes look good, pax are just about off so I go up into the jetway. Crew is packing up for the hotel and says the plane is good. At this point I can walk away and the plane is still on the last mechanics' airworthiness release.

Now if the crew says, 'We put needs oil and the nbr 2 vcr is inop in the book', the last AR isn't valid anymore. I now have to fix the problem or add it to the Maint Carry Over list per the MEL. Then last I sign a new AR. At our company there is no written pilot acceptance. If Capt'n Over doesn't want to accept the aircraft he calls ops. Of course Maint will also be involved, but the sitck shakers never put anything in the book saying they like the aircraft. Ops also deals with all of the fueling paperwork. As a mechanic the only time I see a fueler is if there is a problem fueling the plane.

Quoting DALMD88 (Reply 25): At our company there is no written pilot acceptance.

What document transfers the Pilots acceptance of the Aircraft from Mx.

Quoting DALMD88 (Reply 25): Ops also deals with all of the fueling paperwork.

Do you mean Flt Ops or Grd ops.
Out here its Mx.
regds
MEL

Mel,

None of the operators I've worked for have a document of acceptance for the flight crew. All they have ever needed is a clean logbook with the appropriate check signed off. In our program, it is possible that the check was done several legs ago.

Quoting Fr8Mech (Reply 27): None of the operators I've worked for have a document of acceptance for the flight crew.

Interesting.Out here there has to be a paper proof of Accountability stating,the Refuelling carried out as per approved procedures,the Check concerned carried out with Signature & no of person responsible.The Pilots signs off the doc with his ALTP no & retains the FSR Book,while the original is kept by Mxz & fwded within 24hrs to QC dept.
regds
MEL