Improving Direct Operating Cost (DOC) help please

[Bearcat F8F]

Hi guys,

I need to improve the DOC of the Fokker F27 specifically in terms of the avionics and control system (if applicable). Searching google for an exact definition of aircraft DOC is proving a bit difficult as most sites just give some formula to calculate it but don't really mention anything specifically in terms of time-scales involved.

We are told that modifications have to be cheap because of DOC. So how do I justify a new avionics suite for the F27 to improve DOC? Does it need to pay for itself in a week, a month, a year?

And the second thing is, would it be feasible to change the control system to something else (e.g. FBW) for lower maintenance costs? Again, I am not 100% by which point a modification has to pay for itself.

(P.S. I know its stupid "improving" the F27 as its obviously a century behind modern technology but nonetheless that's the little assignment I need to do).

Any info and advice welcome.

Thanks

[Linktrained]

" The Operation of Airlines " by J.E.D.Williams, although perhaps dated, is of a similar vintage to the F27. (I think that it may have been digitised.)

Some of the aspects you must know already.

How long do you expect the aircraft to be in service, a week, a year or ten years
How many flying hours or landings can be anticipated in that period. Then add 10%, because you never can tell !
How readily are ordinary routine spares available ?
To get the aircraft airworthy requires a C of A. For a projected service life of one week... or one flight... THAT IS EXPENSIVE.

At one stage in history, aircraft were "Cheap to buy- and dear to fly." Now the pattern is reversed to "Dear to buy-and (relatively) cheap to fly." because of the economies of scale, with many more passenger/miles/day.
( An Empire flying boat cost £37,000, new.)

Good luck
LT

PS I am not an engineer and I have never even boarded an F27, but I suspect that installing FBW and then getting it approved as airworthy... MIGHT BE DIFFICULT, to put it mildly !
Upgrading the avionics sounds easier, a new box with a new dial sounds so much simpler.
RR used to supply some engines on a " Power by the hour" contract.
Do some basic calculations for the various alternatives and then graph them out to see if any look promising. Graph paper and coloured felt tips may be sufficient. ( A computer program will tell one the answer that it has been instructed to give, by the programmer.) LT

[Tinstaafl]

Three things come mind: Avionics ie GPS to allow direct instead of via airways, new interior using lighter materials to improve payload, and new engines with better efficiency.

[Wizofoz]

Bearcat.

SERIOUSLY no offence intended- but to even suggest changing a flight control system in a 50+ YO Turbo Prop to FBW "To save money" shows an incredible lack of knowledge of the basics of running a commercial aircraft operation.

You would be up for- seriously- MILLIONS of dollars (in fact it goes beyond that- it simply wouldn't be possible).

There are many, many faqr modern, fuel efficient types available than the F-27. Why are you even considering the type?

May I ask what, where and by whom you are propossing this operation?

ETA- AH! This is a Uni Project?

Gotcha.

Yes, it will still depend on the actual end-use of the aircraft as to how much modification is actually worth the cost- weight saving interior is easy, avionics less so, FBW- Forget it!!

[Bearcat F8F]

Thanks guys. I am tasked specifically with the avionics and control system if it's applicable. The materials, engines or any stability changes are not my job. But any specific avionics/ GPS you might suggest, I will have a look at. Is there any good place where I could find out the cost of second-hand units?

Three things come mind: Avionics ie GPS to allow direct instead of via airways, new interior using lighter materials to improve payload, and new engines with better efficiency.
So are you saying its better to stick with just the addition of a GPS unit Vs a G1000 suite or something along those lines? I wish I could figure out how much in maintenance this could save :suspect: But good thinking on flying direct. Is this generally allowed in the real world? I am not IFR rated so possess limited knowledge.

ETA- AH! This is a Uni Project?
Yes, correct. Which is why I said its a stupid idea but nonetheless I have to do it lol

[Bearcat F8F]

Is there a possibility to install some sort of FMC that would tailor all the a/p and throttle responses to a lower operating cost? Or am I talking out of my ass now... :rolleyes:

I'm guessing the F27 doesn't have any sort of FMC, so could this possibly be a good option to install one?

But most importantly, is there any relatively easy formula to calculate DOC? I googled it but all the ones I have come across so far seem complex in that I wouldn't know the value of some of the variables.

Is there a way of doing this without touching a complex equation? i.e just say that maintenance savings = something and more efficient operation can be estimated as = something, hence the saving over X amount of hours = something? Or is this a bit daft?

[fantom]

I may be being simplistic here but, having flown the F27 and the Airbus family, we are talking apples and pears.

Savings on DOCs for an F27 cannot involve changing the basics of the thing - far, far too expensive to develop. Anyway, which F27 are we talking about; a basic one or a curly-prop one?

You are down to crew costs (first option), airfield fees, fuel price and engineering costs. OK, you can mix these up with FOCs a bit but we're talking costs here.

Will the local authority permit only one cabin-crew? I am assuming you have about 44 seats.

What is the local equivalent of Eurocharges (ATC fees)? Any room there?

It never ends...

[Wizofoz]

Actually, with modern electronics, something as simple as a class one EFB- nothing but a Windows lap-top and tailored software- could allow you to optimise feild calculations (including Flex thrust which has a substantial effect on DOC) and even do a good job of calculating optimum levels and speeds.

Add an RNAV approved GPS (Just a panel mounted GARMIN will do) and you have direct-to capability.

Beyond that, I don't see what a G1000 panel would do for you- they are a great interface, but only give the same info analog instruments do in a nice, user freindly fashion, but at a high cost!

If the exersize in purerly DOC without factoring ROI, I guess you might make a case for lower operating costs.

Similarly, FBW improves handling and saftey, but not DOC unless the airframe is designed for it from inception (e.g reduced drag from relaxed stablility) so EVEN disregarding the prohibitive cost, I can't see that helping DOC.

[Vc10Tail]

Why not just get a Fokker 50?

[Bearcat F8F]

Wizofoz, ok I gocha. The FBW was just a "maybe". Its the avionics or any part of the intellectual brain of the a/c that is of interest to me.

Can you suggest anything besides a Garmin GPS unit and a laptop? Speaking of the laptop, I think we need to "modify" the a/c so I might have to stick an FMC unit into the aircraft or somehow make the laptop part of the flight deck... sort of what Airbus is doing.

Is there anything I can do with the instruments? Even if not a G1000, some smaller King Air-style MFD units maybe? Would they lower maintenance costs?


Vc10, because the project is to modify an F27, not an F50. There is nothing I can do about that. Personally I would much rather be modifying a 767 or an old 747 but I don't have a choice :ok:

[Empty Cruise]

Ok - any limitation on where the aircraft must operate?

If you can accept daylight VMC only - take the aircraft off IFR capability and tear out all instruments but those required for day VFR.

You have saved weight, mx cost and improved dispatch reliability tremendously. OK, you can only fly cargo in N Africa and the ME, but I bet your assignment didn't stipulate anything about that ;-)

[avionimc]

F8F – Forget all the Hollywood stuff such as FBW, A/T, FMC/FMS, etc. Ask your uni professors if they actually know anything about aviation and if they have any common sense! Tell them you cannot take a Ford Model T and convert it into a “would be” late model (2013) Mustang, or Prius.

The F27 was a very fine aircraft. If I had such an aircraft [project], time & money, here is what I would install (or something like):

Dual Garmin G600 SVT (with synthetic vision – e.g., L3 IRIS or Max-Viz 1500, or Max-Viz 600)
Dual GTN 750 (or one GTN 750 and one GTN 650)
L3 TRILOGY ESI-2000
GWX 70
GTX 33ES
GTS 8000 (TCAS II) or GTS 850 (TCAS I)
Sandel ST3400
etc.

This would make a real cool flight deck and, I would fly the bird to the AirVenture!

But, most important is replacing the RR Dart engines with newer, quieter, easy to maintain and more fuel efficient turboprops. You will have to research which “today” turboprop make & model would be appropriate (and which shp is required).

There are probably no STCs, therefore field approval F337s would have to be obtained. All this could probably be done with the FAA; but no chances with EASA! IMHO.

Actually, I would try to get a FAA special airworthiness certificate - Experimental - Exhibition (or Research and Development in your case), no STCs required.

Improving “DOC” of a F27 Friendship is a futile exercise, but again, you will have a real cool airplane, the envy of many museums. Good Luck,

[Linktrained]

Perhaps the cheapest way of reducing the DOC of an aircraft is to operate EMPTY. You could even remove the seats, too !

I lack information on the effect that this would have on the F27. A ball park figure for a B707 was that each extra tonne used 30kg./hour, ie. on a 7 hour flight this one tonne would have used 210 kg. more fuel.

To reduce the total cost, one airline was said to schedule flights to depart Base in the early evening - because otherwise ground staff would have to be paid overtime. Flight crew were not paid extra for night flying !

Can your F27 be operated at night to your destinations ? Night curfews may restrict some operations. Or can reduced landing fees be arranged at times when the traffic would otherwise be slack ? You could increase the profitable utilisation by keeping operating throughout the 24 hours. Passengers may be prepared to travel at 2am for a low enough fare.

Passengers normally return. Freight tends to have a single flight, so a different return load ought to be found, if possible.

Freight can be carried throughout the 24 hours. Not all freight comes under the traditional list of "Urgent, Fragile or Valuable". While a freight door can make turnarounds faster, I carried a lot of 40 gallon oil drums, which had been loaded through an ordinary passenger door, and some garden wheel barrows we carried 3000 nm.!

There is a "Zero Distance Cost" to be considered, somewhere, ie. all those costs without actually moving the aircraft.

LT

[Tinstaafl]

Bearcat, regarding the GPS I certainly was *not* thinking about installing a G1000 nor anything else of that ilk. This is a transport category aircraft so approvals for changes can be expensive. Whatever GPS that supports datacard or USB upgrades (for cost effective database upgrades) that can gain installation approval. If GPS approaches are available in the region of operation then also a GPS that's approved for GPS approaches too.

[dusk2dawn]

What is it uni wants? Isn't this more or less an exercise in defining and controlling DOC?
I mean... there is no universal definition of DOC so go ahead and decide that certification and everything that requires a one-time king-size payment is irrelevant to your definition of DOC. Then load your F27 with whatever equipment that has even a microscopic effect on DOC.

[Bearcat F8F]

Thanks a lot for the help and suggestions guys.

I know its very stupid that our assignment doesn't have a certain criteria for operations. In other words its presumed we can use the aircraft for whatever we want. So with each modification I could perhaps tailor it to a specific type of operation. i.e. for ferrying freight in Africa and no night capability etc.

My bit in particular is to do with systems and avionics. Someone else is considering engines/ materials etc.

I think I have a much clearer picture now of what I can do depending on the operating environment however I still find the available formulas for DOC calculation quite confusing. I can't find anything simple and straight forward that I we can use to calculate DOC but I guess that's the nature of DOC.

[avionimc]

i.e. freight in Africa and no night capability
Usually freight is flown at night, even in Africa. And, night capability is not expensive, basically only a few light bulbs.

[Bearcat F8F]

Ok I see :ok:

But given its all dirt strips I assume no need for IFR equipment? Just an iPad?

And is there anything I could do with the landing gear to improve DOC? Or is it one of those things that is really pretty much the same now in the 21st century as it used to be in the 50s?

[avionimc]

no need for IFR equipment?
YES, you do need the aircraft to be fully IFR capable (in Africa, and anywhere else for that matter)! And that too, is not a big deal, nor is it expensive, compared to being unable to dispatch the aircraft in marginal [VFR] WX, or compared to the cost of fuel burn of such aircraft. Also, many regulators mandate the aircraft to be IFR, and the pilots to be instrument rated, to operate VFR at night. NB: Only small private recreational aircraft such as LSA are strictly VFR.

[barit1]

PAX or freight ops? Does the aircraft fly a time-critical schedule to interface with a daily central package-sort schedule? If so, component reliability might be a major issue, so research in this arena might reveal weak points it its systems.

ABF was flying rehabbed DC-9s in such a operation and had an instrument failure at an outstation. They had to hire a LearJet to deliver a replacement. This was the incentive for them to investigate retrofitting DC-9s with glass cockpit - lower DOC plus reliability.

Engine (maybe prop) upgrade could pay off too in fuel savings; Many carriers liked the CFM56 refit on the DC-8. The airframe had lots of structural life left, but needed modern engines.

[Bearcat F8F]

ABF was flying rehabbed DC-9s in such a operation and had an instrument failure at an outstation. They had to hire a LearJet to deliver a replacement. This was the incentive for them to investigate retrofitting DC-9s with glass cockpit - lower DOC plus reliability.
So you re saying that a glass cockpit might be a good idea? as you can see above, it was suggested that a glass cockpit may be a rather bad choice to lower DOC.

[barit1]

Given the nature of the ABF operation - hub & spoke, daily pkg sorting window, timing is everything - reliability was a major issue. I am not sure if the glass cockpit would drop into the beancounters' DOC bin, but it was apparently a big issue for them. :=

To be honest, I do not know if it was finally adopted; I only know that they had one glass bird (20 yrs ago) flying with an Experimental tag. Even if it were an increased DOC, if it provided greater earnings (lower refund & reputation losses), it might have been seen as an worthwhile upgrade.

[BlogName1a]

Still haven't read the reason, the impetus for changing out the 'system'.

I saw a flight department close because the chief pilot took months to change a GNS XL to a UNS1. He said the GNS was 'dangerous'.

Long before glass and GPS units, planes still went from Point A to B. Big surprise huh?

This thread lives and dies in the world of people wanting new toys in the cockpit and having such a lack of situational awareness that the only way they can fly comfortably is by following a little white airplane on a screen.

[DaveReidUK]

I need to improve the DOC of the Fokker F27 specifically in terms of the avionics and control system (if applicable). Searching google for an exact definition of aircraft DOC is proving a bit difficult as most sites just give some formula to calculate it but don't really mention anything specifically in terms of time-scales involved. You appear to be considering operating costs purely in terms of maintenance cost, whereas that only accounts for a proportion of DOCs.

A good start might be to establish, for typical F-27 operators, what proportion of DOCs is actually represented by maintenance. That will then give you a better idea of the maximum savings that maintainability improvements would produce, which you can then compare with the cost of any such changes.

[Wizofoz]

Bear,

WRT the laptop, simply make it an installed class 2 EFB and that should cover the "Modification" criteria. It could also cover a lot of the functions of an FMC at a much lower cost.

[autoflight]

You mentioned mods cannot be too expensive. Right at the beginning of your assignment it will be necessary to define the chosen F27 model and the limitations of your studies, as it does not sound like this has been done for you. If all those working on the project could agree on a common philosophy, it would be a tiny bit more like the real world where there would be an overall project manager for such considerations.

You might just need to show innovative thought, not just a rehash of what some VIP operator did to one aircraft 20 years ago.

F27 had water injection available for take-off. This provided a respectable amount of extra power for more difficult conditions or for high weight take-off. If these conditions did not exist, water injection is not needed, meaning there was less power and quite a bit less wear on the engine. Reduced wear is a DOC advantage. That is an existing procedure, but could be further refined by "reduced thrust take-off", common on modern jets.

Using a Dry Take-off with further reduction in power would further reduce engine wear. A laptop (avionics) program for each planned airfield could provide the further refined take-off power settings. You would need to co-operate with those who are responsible for engines. Maybe such co-operation is an intended feature of your studies?

Improved navigation would be relatively inexpensive. Even the type of GPS fitted to light aircraft would be usefull. One navigation advantage is more direct tracking can be authorised by ATC with this equipment. A less obvious advantage is that fast and accurate recording of head and tailwinds can help in selection of efficient flight levels. Lower cruising levels are less efficient, but if there is a tailwind at 10000 ft and a 50 knot headwind at 20000 ft, a lower level should be considered to save time and therefore fuel. Again, co-operation with those responsible for operating procedure DOC would be essential.

Some older electronics might be expensive to maintain. Over a few years, a modern full or partial suite of communication and navigation gear might reduce DOC.

I cannot think of any practical thing that could be done with flight controls. Closest would be a modern autopilot. Expensive to fit, but might also be less expensive to maintain. There would be obvious certification problems that might be very costly. Rather than just not mention controls, there would be scope in your studies to list modifications that were considered but rejected.

[Bearcat F8F]

Still haven't read the reason, the impetus for changing out the 'system'.

I saw a flight department close because the chief pilot took months to change a GNS XL to a UNS1. He said the GNS was 'dangerous'.

Long before glass and GPS units, planes still went from Point A to B. Big surprise huh?

This thread lives and dies in the world of people wanting new toys in the cockpit and having such a lack of situational awareness that the only way they can fly comfortably is by following a little white airplane on a screen.
Relax! Its just a university project. We are not doing anything, we are just proposing mods to improve DOC so I best come in with something as opposed to saying that its a pointless exercise and I should get and A for doing no work on this whatsoever as the F27 is not worthy of being modded at this time in history. http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/evil.gif


You appear to be considering operating costs purely in terms of maintenance cost, whereas that only accounts for a proportion of DOCs.

A good start might be to establish, for typical F-27 operators, what proportion of DOCs is actually represented by maintenance. That will then give you a better idea of the maximum savings that maintainability improvements would produce, which you can then compare with the cost of any such changes.
The DOCsys formula I am using contains "depreciation", "fuel" and "maintenance". I could also facor in delay and cancellation costs but this is outside my scope of knowledge.

My biggest problem is the "fuel" part of the formula. The calculation for this is extremely complex with variables I simply can not fimd out from the public domain so I have no idea how to apply the formula or if I can just use verbal reasoning with respect to a fuel saving for a system.



WRT the laptop, simply make it an installed class 2 EFB and that should cover the "Modification" criteria. It could also cover a lot of the functions of an FMC at a much lower cost.
Awesome, thanks a lot! http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/thumbs.gif



You mentioned mods cannot be too expensive. Right at the beginning of your assignment it will be necessary to define the chosen F27 model and the limitations of your studies, as it does not sound like this has been done for you. If all those working on the project could agree on a commom philosophy, it would be a tiny bit more like the real world where there would be an overall project manager for such considerations.

You might just need to show innovative thought, not just a rehash of what some VIP operator did to one aircraft 20 years ago.

F27 had water injection available for take-off. This provided a respectable amount of extra power for more difficult conditions or for high weight take-off. If these conditions did not exist, water injection is not needed, meaning there was less power and quite a bit less wear on the engine. Reduced wear is a DOC advantage. That is an existing procedure, but could be further refined by "reduced thrust take-off", common on modern jets.

Using a Dry Take-off with further reduction in power would further reduce engine wear. A laptop (avionics) program for each planned airfield could provide the further refined take-off power settings. You would need to co-operate with those who are responsible for engines. Maybe such co-operation is an intended feature of your studies?

Improved navigation would be relatively inexpensive. Even the type of GPS fitted to light aircraft would be usefull. One navigation advantage is more direct tracking can be authorised by ATC with this equipment. A less obvious advantage is that fast and accurate recording of head and tailwinds can help in selection of efficient flight levels. Lower cruising levels are less efficient, but if there is a tailwind at 10000 ft and a 50 knot headwind at 20000 ft, a lower level should be considered to save time and therefore fuel. Again, co-operation with those responsible for operating procedure DOC would be essential.

Some older electronics might be expensive to maintain. Over a few years, a modern full or partial suite of communication and navigation gear might reduce DOC.

I cannot think of any practical thing that could be done with flight controls. Closest would be a modern autopilot. Expensive to fit, but might also be less expensive to maintain. There would be obvious certification problems that might be very costly. Rather than just not mention controls, there would be scope in your studies to list modifications that were considered but rejected.
Thanks for the info. And speaking of the a/p, could it be removed altogether to save weight? Ok so the crew will have to have a decent workout but there's other turboprops out there that fly happily without a/p. Just curious if this is a decent enough weight and maintenance saving?

[avionimc]

Blogname: Long before glass and GPS units, planes still went from Point A to B. Big surprise huh?
Not true, without RNAV (or GPS) you could not, and still cannot, file IFR direct routing, therefore, IFR certified panel-mounted "GPS" is an important savings factor in DOC.

F8F ... speaking of the a/p, could it be removed altogether to save weight? ... fly happily without a/p
Correct, several small PAX commuter airliners and most freight turboprops do NOT have autopilots as standard equipment or, they were removed (e,g., Beech 1900D, etc.). And, as I mention it below, your original A/P will NOT work! Therefore, best to remove it entirely and donate it to a museum, along with the rest of the original avionics.

The real problem with old, obsolete avionics such as the systems you find in a F27 is that they will probably not work for very long, if they do work at all in the first place. The avionics in F27s date from the 1950s (and up to the early 1980s for late models), they cannot be repaired and it is [almost] impossible to find spare parts. Reason why you need entirely new, modern day IFR avionics suite (which, incidentally, are also lighter in weight and offer much more functionality, redundancy and safety).

EFBs (and other gizmos such as iPad, etc.) do not replace panel mounted avionic systems, they are merely tools to improve productivity to some degree within large airlines with large number of flight crew members and well established SOPs. Some airlines use them as an approved way (approved case by case) to store and replace paper documents such as instrument approach plates, airport taxiway diagrams, aircraft POH, MEL, company OPS manuals, etc. EFBs are never approved for navigation, they are usually assigned to a flight crew member, not to the aircraft (NB: if you employ a large number of flight crew members, savings can be substantial). They are not essential in your case, with just one aircraft, just a distraction, IMHO.

Not sure if you have looked into the Garmin suites I mentioned in an earlier post, here are some pics of older turboprops after "affordable" avionics upgrade and, an interesting G1000 video. Glass panel, airport taxiway diagrams and more.

http://kingair.org/wp-content/uploads/2012/08/590937-500x375.jpg
http://www.bartintl.com/sites/default/files/headlines/01_48.jpg
http://www.beechtalk.com/forums/download/file.php?id=29876
Total installed cost less than 200K USD (no A/P included).

pB_NUcBzNwk
Total installed cost slightly more than 300K USD (fully integrated GFC700 A/P included)

[barit1]

As you work through the problem, one aspect you will confront is this: "Is the problem adequately specific? Are there enough constraints to determine if a given 'solution' is appropriate?" Anticipated service life of the mod(s) is an example, in which case you could calculate a break-even point where the mod has its initial cost covered and begins to pay off.

OTOH the problem can be OVERSPECIFIED - one constraint conflicting with another. :=

In either case, point this out to the instructor - backed up of course with an example or two.

[Bearcat F8F]

avionmc, thanks for the opinion, much appreciate it. WRT to EFBs I honestly think its rude not to include one. In the worst case scenario, an iPad can be considered a Class 2 EFB. Although I'm unsure if an iPad can be loaded with the required software for takeoff thrust calculations etc. Maybe it can? If not, I am keen on finding some affordable EFBs as it sounds like it's a pretty easy way to improve engine wear and tear, fuel burn and reduce weight.

With that said, I do very much appreciate the need for a new instrument panel. That King Air pit looks great, which brings me onto the next point where I'm struggling:

Is there a place online that I could find out some of the costs associated with these bits of equipment? i.e. new GPS, avionics suite, EFBs etc? Ideally I would also need to work out the depreciation cost and maintenance cost of the unit for DOCsys calculations. But even just the starting cost of buying one of these either new or 2nd hand would be great.

P.S. Whats the reason for having 2 (identical?) GPS units like in the King Air cockpit above?

And also, which GPS's support direct routing? All of them?

[stallfail]

I think I have a much clearer picture now of what I can do depending on the operating environment however I still find the available formulas for DOC calculation quite confusing. I can't find anything simple and straight forward that I we can use to calculate DOC but I guess that's the nature of DOC.

DOC is per definition operating costs which are directly attributable to the aircraft being operated. The rest are IOC(Indirect Operating Cost), DOC+IOC= TOC (Total Operating Cost)
DOC normally consists of four major cost categories ie. crew cost, fuel and oil cost, depreciation cost (including insurance cost) and maintenance cost.

In your case it might be more transparent to apply the LCC(Life Cycle Cost, the total cost incurred by an item along its entire life / life cycle)concept,instead of the standard Cost Benefit Analysis (CBA) methods. the research is focused on aircraft maintenance and engineering, as the main subject !!!

From LCC point of view, all cost categories resulting from aircraft acquisition and exploitation are included in the LCC, only two cost categories are excluded : Ticketing/Sales/Promotion and General Administration cost !!!

[Bearcat F8F]

Would something like this dual display pay for itself in a year of operation by saving on maintenance costs associated with the original 1950s avionics of the F27?

Garmin G3X System Dual Display (http://www.gps.co.uk/GPS/Garmin-Panel-Mount/Garmin-G3X-System-Dual-Display/p-94-277-802/)

So this G3X is £6594. Sounds pretty expensive. Is there any cheaper 2nd hand units such as this? The thing I don't know is actually how much it costs to maintain the original avionics of the F27 in the 1st place. Any guesses on that? Pretty impossible to find such figures online.

DOC is per definition operating costs which are directly attributable to the aircraft being operated. The rest are IOC(Indirect Operating Cost), DOC+IOC= TOC (Total Operating Cost)
DOC normally consists of four major cost categories ie. crew cost, fuel and oil cost, depreciation cost (including insurance (http://www.pprune.org/newreply.php?do=newreply&noquote=1&p=7677722#) cost) and maintenance cost.

In your case it might be more transparent to apply the LCC(Life Cycle Cost, the total cost incurred by an item along its entire life / life cycle)concept,instead of the standard Cost Benefit Analysis (CBA) methods. the research is focused on aircraft maintenance and engineering, as the main subject !!!

From LCC point of view, all cost categories resulting from aircraft acquisition and exploitation are included in the LCC, only two cost categories are excluded : Ticketing/Sales/Promotion and General Administration cost !!!
The DOCsys formula (for aircraft) has 3 major components. Depreciation + Fuel burn + Maintenance.
We were told as part of the assignment that mods have to pay for themselves within a year or so.

[stallfail]

The DOCsys formula (for aircraft) has 3 major components. Depreciation + Fuel burn + Maintenance.

Well, this might apply to your DOCsys formula.............:suspect:

In the real world, it looks more like that.........

Method for Calculating Direct Operating Cost
The following is an estimation method known as DOC+I (Direct operating cost plus interest). This method is based on the work of Liebeck and has been applied by Ross
for wide body commercial aircraft. By definition the DOC+I method takes into account the following operating expenditures; flight & cabin crew cost, airframe maintenance, engine maintenance, landing fees, depreciation, interest, and insurance.
Flight Crew & Cabin Crew

The flight deck and cabin crew cost are all based on Block Hours (BH), which is equivalent to the number of trips per multiplied by the average flight time per trip. For
the flight crew there salary is a function of the maximum takeoff weight of the aircraft as
seen in Equation 1. The flight attendants or cabin crew cost is based on an assumed pay rate of 60 dollars per hour.
(# ) (440 0.532*( /1000) gross Flight Crew = BH × of flight crew × + W (Eq. 1) Cabin Crew = BH ×(#of flight crew)×60 (Eq. 2)

Airframe Maintenance
Cost of airframe maintenance is broken down into three parts; labor, materials, and
burden or the cost of taking the aircraft out of operation.
Airframe Maintenance Labor:
Notice that for both the labor and material cost, are based on a historical curve fit developed by Liebeck and are dependent of the number of trips per year, average trip time and the airframe weight.

Landing Fee
The landing fee is based on the operational empty weight of the aircraft and an average of
landing fees in the United States. They may heavily vary in Europe, with possible
additional fees such as NOX emissions or community noise. However this is not captured in this method.

Depreciation, Interest & Insurance
For all of the following methods the total airframe cost must be known, which can be
found using methods found in Raymer. Notice that all of the following equations are
dependent on gross weight that will be found by your sizing code.
Depreciation (1 residual ) Airframe Cost Airframe Spares Airframe Cost Engine Spares Airframe Cost

For the interest calculation it is ok to set the future value of the aircraft to zero since it is difficult to predict this value, especially at the very early stages of preliminary design. Finally, from all of these the total direct operating cost of a commercial transport can be
found:
DOC = Flight Crew + Cabin Crew + Airframe Maintenance + Engine Maintenance +Depreciation + Insurance + Interest

[autoflight]

Bearcat, You seem to be on a steep learning curve here on pprune, so it seems like you came to the right place.
Reading between the lines, I think the details of your set F27 project are a bit thin. For instance, is your F27 a clapped out piece of s*** that has had a hard life in some aviation backwoods, or is it a VIP aircraft with low hours and no expense spared sourcing a collection of unused or expertly overhauled avionics spares that came with the aircraft? Your class colleages would be interested to know if it was fitted with low time engines and props and who completed the last major service and when.
In the absense of such information, you might need to make a formal assumption about the state of the aircraft and spares.

[toffeez]

That is the biggest amount of academic bull**** that I've heard in my 40 years in the industry. Only the Lufthansa Cost Method was as ridiculous.

AIRLINES DON'T HAVE "METHODS" THEY HAVE CASH IN AND CASH OUT.

Bearcat F8F: Concentrate on cash, cash, cash, not formulae. Cash in vs cash out is what matters. Forget classic DOC methods which include depreciation. Depreciation is not a cost. That's just accountant's mumbo-jumbo. Think about what you could take to the bank (or out). If the changes don't pay off in a year or two your airline could be bust.

Stallfail: what the fuk has cabin crew cost got to do with the problem in hand? Bearcat has to concentrate on the changes, not worry about what stays the same. Luckily academics don't run airlines. At least not successful ones.

P.S. Bearcat: JUST CONCENTRATE ON WHICH COSTS CHANGE, BEFORE vs AFTER. DON'T TRY TO LIST ALL DOC ITEMS. ITS POINTLESS.
You've been given a task unrelated to the real world. You have to do it, but remember the tosser's name for future reference!

[Bearcat F8F]

toffeez, Yes, completely agree. I am concentrating on the costs involved in the difference between initial purchase cost + maintenance Vs how much it saves. These DOC formulas are driving me mad. We were not given any realistic data to start with so there is no way on Earth any student could get access to all the costs associated with a F27! so yes, I'm doing exactly what you have suggested.




autoflight, Thanks. I would be quite interested in finding out more relevant equipment for the a/c though. What is the cheapest useful GPS taht I can get for example?

And I can not find a good classifieds website to see listings of 2nd hand units so struggling to find out how much these units cost to buy and maintain and install. Any help appreciated.

[Roger Greendeck]

Aircraft modification such as flight control and engine retrofits etc unless they are an existing mod are going to cost too much to consider for any normal size operator. So other than removing anything you don't need, to save weight, there is little you can do on this front.

Avionics mods can save you three thing: maintenance costs, weight, and time (direct tracking and lower minimas so less holding or diversions). The equipment in an original F27 will be pretty old and hard to maintain and weighs lots. Wholesale replacement of avionics is expensive but if you can't maintain it the opportunity costs from missed flights could cover the high cost. If the aircraft has supportable avionics keep what you can and go simple. Integration costs can be very high so adding a stand alone GPS will be better value than trying to fit a fully integrated solution. .

Best bang for buck is likely to be dual TSO C145 or 146 GPS and remove the ADF(s). 145/146 allows you to use the GPS as your only destination nav aid which means you can get into more places more often. The ADF then becomes superfluous. Removing it saves you maintenance costs and weight.

[Roger Greendeck]

Not sure when your assignment is due but if its after Avalon and you can get yourself along to a trade day there will be lots of component companies there who can give you rough order of magnitude costs.

[Bearcat F8F]

Avalon in the UK? Afraid its a bit far for me to go just for a university project. Thanks for the suggestion though.

Is there no good websites where they sell used 2nd hand avionics? All the websites that I come across are limited in the amount of equipment they sell or they don't have a price tag online.

[Bearcat F8F]

Aircraft modification such as flight control and engine retrofits etc unless they are an existing mod are going to cost too much to consider for any normal size operator. So other than removing anything you don't need, to save weight, there is little you can do on this front.

Avionics mods can save you three thing: maintenance costs, weight, and time (direct tracking and lower minimas so less holding or diversions). The equipment in an original F27 will be pretty old and hard to maintain and weighs lots. Wholesale replacement of avionics is expensive but if you can't maintain it the opportunity costs from missed flights could cover the high cost. If the aircraft has supportable avionics keep what you can and go simple. Integration costs can be very high so adding a stand alone GPS will be better value than trying to fit a fully integrated solution. .

Best bang for buck is likely to be dual TSO C145 or 146 GPS and remove the ADF(s). 145/146 allows you to use the GPS as your only destination nav aid which means you can get into more places more often. The ADF then becomes superfluous. Removing it saves you maintenance costs and weight.
So a GNS 430? Any better solutions than that? So far I found a reconditioned 430W for £4674. Would maintenance/ dircet tracking and weight save more than this cost + installation cost? I know it obviously depends on the situation but hypothetically?

[stallfail]

That is the biggest amount of academic bull**** that I've heard in my 40 years in the industry. Only the Lufthansa Cost Method was as ridiculous.


Great, than Bearcat will very probably succeed !!!

You missed the point, mate. It does not matter if the task is related to real life or not, it appears to be a seminar, where some worldly innocent tutor comes up with a ridiculous task which has to be solved by Bearcat.................

Stallfail,what the fuk has cabin crew cost got to do with the problem in hand? Bearcat has to concentrate on the changes, not worry about what stays the same. Luckily academics don't run airlines. At least not successful ones.

Just come down and read my post, I have simply listed the DOC items and did not comment on anything else........:ugh:


Look at Bearcat's inital post:

Hi guys,

I need to improve the DOC of the Fokker F27 specifically in terms of the avionics and control system (if applicable). Searching google for an exact definition of aircraft DOC is proving a bit difficult as most sites just give some formula to calculate it but don't really mention anything specifically in terms of time-scales involved.

We are told that modifications have to be cheap because of DOC. So how do I justify a new avionics suite for the F27 to improve DOC? Does it need to pay for itself in a week, a month, a year?

And the second thing is, would it be feasible to change the control system to something else (e.g. FBW) for lower maintenance costs? Again, I am not 100% by which point a modification has to pay for itself.

(P.S. I know its stupid "improving" the F27 as its obviously a century behind modern technology but nonetheless that's the little assignment I need to do).


In my initial reply, I gave a definition of DOC (academically/ iaw. IATA) and stated that the LCC concept should apply,instead of the standard Cost Benefit Analysis methods.

Simple : Focus on Modification costs, Changes of operating costs, changes of revenue, length of life cycle.

Bearcat, there are defined ways of cost and potential saving estimations for aircraft modifications, although you need to collect a lot of data.
Apparently your pro did not provide relevant information, so you are not able to provide accurate numbers ...............

LCC-OPS model:

1)Modification Cost (Cm)
by calculating Labour costs, Material costs, Tool costs, Downtime costs

2) Changes of operating cost per trip (Co)
by calculating Changes of fuel and oil cost (Cof), Changes of fuel cost due to weight changes (Cofw), Changes of fuel cost due to parasite drag (Cofd), Changes of fuel cost due to (direct) power consumption changes (Cofp), Changes of fuel cost due to changes of fuel up-lift (Cofu), Change of oil cost (Cofo), Change of maintenance cost (Com), Changes of routine maintenance cost (Coms), Changes of none routine maintenance cost(Comn), Changes of unscheduled maintenance cost (Comu), Changes of maintenance dependent cost (Comd), Changes of required spares (Comp), Annual changes of depreciation cost (Cod)

3) Changes of revenue
Changes of revenue due to availability changes (Ra), Annual changes of revenue due to changes of scheduled maintenance time (Ras), Changes of revenue due to Changes of none routine maintenance time (Ran), Changes of revenue due to Changes of unscheduled maintenance time (Rau), Changes of revenue due to Changes of functional performance (Rf), Changes of revenue due to capacity changes (Rfc), Changes of revenue due to speed changes (Rfs) Note:Block speed normally depends on ATC

[Roger Greendeck]

GNS430W is TSO C146a so that will meet your needs. That price is pretty low compared to having to hold for an hour (800 litres of fuel) or divert due weather. Not sure of your installation cost but can run into £1000s. Even then you will save that money pretty quickly.

Higher end FMS's are going to be in the order of £50,000 plus installation. So the savings need to be that much more.

[Bearcat F8F]

stallfail (http://www.pprune.org/members/103407-stallfail), don't worry about opinions here. I read your posts and thanks for the info. I appreciate what evryone has to say and I can then pick out info which I need or dont need.

Roger Greendeck, I see thanks for the info. Any idea on maintenance costs for a GNS 430W? Whats involved in the maintanence of these GPS's?

And, why is it occasionally that aircraft are fitted with 2 identical GPS units?

[DaveReidUK]

we are just proposing mods to improve DOC so I best come in with something as opposed to saying that its a pointless exercise and I should get and A for doing no work on this whatsoever as the F27 is not worthy of being modded at this time in history.I disagree.

If you were to take a selection of the technically-feasible mods that have been mooted here and, after a careful cost/benefit analysis, conclude that none of them generated a positive net value over a reasonable period, then that would (or should) satisfy the aims of your assignment.

If, on the other hand, you are expected to come up with cost-effective mods that would pay back the non-recurring cost with DOC savings, and that no F-27 operator in the last 55 years has though of, then you should be seriously considering changing your tutor or educational institution.

[Bearcat F8F]

I disagree.

If you were to take a selection of the technically-feasible mods that have been mooted here and, after a careful cost/benefit analysis, conclude that none of them generated a positive net value over a reasonable period, then that would (or should) satisfy the aims of your assignment.

If, on the other hand, you are expected to come up with cost-effective mods that would pay back the non-recurring cost with DOC savings, and that no F-27 operator in the last 55 years has though of, then you should be seriously considering changing your tutor or educational institution.
In the last year, in the last semester of my degree changing tutors or institutions? I don't see it, sorry.

I am not trying to justify stupid modifications through BSing. I am looking at realistic ways of doing it. Given the fact that we have so many unknown variables, I can get away with justifying modifications that might in real life be impossible. But don't assume I am not taking it seriously. I'm sure there are things we can do and perhaps things which have not been done by F27 operators as 90% of F27s are no longer in service.

[autoflight]

Dispose of F27 and DOC zero is a possibility.

Your project is an interesting diversion from the usual tech log threads, though not the first of this type.

Care to share with us more of the actual details of the project that you have been set? Does it seriously have to keep flying or can you consider parking it in a tourist area and turn in into a coffee shop, cocktail bar or similar? It could be called "Get Fokkered". Any other names?

[Bearcat F8F]

Ha-ha. We could call the cocktail bar "Fokk This"

There are no outlined rules or details however I assume that for a 4th year Aeronautical Engineering project, the fact that it has to keep flying is kind of a prerequisite.

On the plus side, I spoke the guy that runs this nonsense and he said we are allowed to justify stuff using verbal reasoning, fractions, cost difference etc and do not require the use of a DOC formula alone. At least this makes it slightly more doable now.

WRT the avionics, any upgrades I do should improve DOC just about anywhere unless the plane really does fly only between 2 dirt strips in the middle of nowhere all year long.

But anyway, I would really appreciate some technical knowledge now regarding the following things:

1) Why do aircraft have dual GPS units?

2) What costs (or time) are involved in maintaining something like a GNS 430W

3) Similarly, what amintenance costs would be involved in maintaining a dual flight display unit such as a Garmin G3X

4) How much could it (very roughly) cost to maintain the original F27 avionics?

Any help, hugely appreciated as this sort of info just can't be found in google search :{

[autoflight]

Bearcat,
Dual GPS that I have used averaged the position and over time, updated the already very accurate inertial position. I expect a new panel mounted dual GPS would just average the two positions and present you with enough nav info to follow the selected tracking. If the position difference of the GPSs was too great it would be another matter and there should be a wealth of experience out there for you to call on.
A question you have not asked, is the actual DOC savings from GPS use. If you have to assume operation in europe, there will be many small direct tracking efficiencies that when added together would slightly reduce DOC. It is the significant direct tracks that can really help and you might only get one of these in a full day of operating.
The tracking distance reduction is not the end of the matter. Your direct track might give a few minutes earlier arrival time that avoids a few times around a holding pattern because of other flights arriving around the same time as your original ETA. If ATC requires passing a certain enroute point at a specific time, your crossing time is more assured with modern navigation gear. Getting something like that wrong is not going to improve the chances of an efficient flight!
Arriving at your destination parking position on time or early usually gives more chance for the subsequent departure to be on time or a little early. There are enough difficulties maintaining a schedule in busy airspace. Every chance should be taken to minimise such difficulties. A good schedule keeping reputation impacts on efficiency. Got to keep those seats filled with happy customers who will go to another operator if your operation is unreliable.
Being late can impact on flight crew duty limitations. If the crew needs an unscheduled rest period where there are no standby crews available, flight has to be cancelled or significantly delayed.
Some of these difficulties can reduced with the accurate navigation available from GPS. From my own experience in Australia, Europe, ME, North Africa and Asia in airline jets (and F27 long ago) the immediate tangible efficiency advantage from modern nav gear can be be about 2%. Your F27 could get about 2%, depending on the routes.
If crew are paid per flying hour, the benefit could be less. My expat crew in one airline could regularly carve 30 minutes flight time from a particular 1 hour 45 minute schedule. We were effectively on a fixed salary. Locals were paid for excess hours. GPS expenditure in your project should therefore be linked to a pilot salary that does not reward greater flight times, meaning the commercial, industrial and operational parts of your project are linked to your avionics part.
Replacing the original nav comms and radar would be based on reliability and maintenance matters and not relate to operational use in the same way as adding GPS.

[DaveReidUK]

Given the fact that we have so many unknown variables, I can get away with justifying modifications that might in real life be impossible.

Fine. Enough said.

[Bearcat F8F]

Bearcat,
Dual GPS that I have used averaged the position and over time, updated the already very accurate inertial position. I expect a new panel mounted dual GPS would just average the two positions and present you with enough nav info to follow the selected tracking. If the position difference of the GPSs was too great it would be another matter and there should be a wealth of experience out there for you to call on.
A question you have not asked, is the actual DOC savings from GPS use. If you have to assume operation in europe, there will be many small direct tracking efficiencies that when added together would slightly reduce DOC. It is the significant direct tracks that can really help and you might only get one of these in a full day of operating.
The tracking distance reduction is not the end of the matter. Your direct track might give a few minutes earlier arrival time that avoids a few times around a holding pattern because of other flights arriving around the same time as your original ETA. If ATC requires passing a certain enroute point at a specific time, your crossing time is more assured with modern navigation gear. Getting something like that wrong is not going to improve the chances of an efficient flight!
Arriving at your destination parking position on time or early usually gives more chance for the subsequent departure to be on time or a little early. There are enough difficulties maintaining a schedule in busy airspace. Every chance should be taken to minimise such difficulties. A good schedule keeping reputation impacts on efficiency. Got to keep those seats filled with happy customers who will go to another operator if your operation is unreliable.
Being late can impact on flight crew duty limitations. If the crew needs an unscheduled rest period where there are no standby crews available, flight has to be cancelled or significantly delayed.
Some of these difficulties can reduced with the accurate navigation available from GPS. From my own experience in Australia, Europe, ME, North Africa and Asia in airline jets (and F27 long ago) the immediate tangible efficiency advantage from modern nav gear can be be about 2%. Your F27 could get about 2%, depending on the routes.
If crew are paid per flying hour, the benefit could be less. My expat crew in one airline could regularly carve 30 minutes flight time from a particular 1 hour 45 minute schedule. We were effectively on a fixed salary. Locals were paid for excess hours. GPS expenditure in your project should therefore be linked to a pilot salary that does not reward greater flight times, meaning the commercial, industrial and operational parts of your project are linked to your avionics part.
Replacing the original nav comms and radar would be based on reliability and maintenance matters and not relate to operational use in the same way as adding GPS.
Thanks, thats helpful. When you say "radar" I assume you mean wether radar? Didn't know the F27 has one? And what's the point in replacing comms? Are the original ones so unreliable/ maintanence-thursty on the F27?

I'm guessing you don't know what's involved in maintaining GPS units? Are they trouble-free for the most part?

Thanks again for the help though, much appreciate it :ok:

[Linktrained]

Look around and see what has been done in the past. On the cross Channel Car Ferry we would do two rotations, there and back, in about 1 hour 20 minutes, carrying three ordinary cars and their passengers in each direction. ( I think that Duty Frees were sold in the rear cabin, too.)
Passengers and cars would take about the same time from arrival at one airport to departure from their destination airport. The chock to chock time was 20 minutes, except on a few longer distance flights. It was usual for a crew to do six trips, 12 landings per day - and it was mostly day flying.
The Company carried a number of export AND import cars to fill the otherwise empty spaces and a certain amount of low priority freight.

I recall that SW Airlines were said to turn a DC3 around in 90 seconds when not refuelling.

It is said that F.W.Smith when at Yale in 1962 got a "C" Grade because when he made a suggestion for an Air Freight Carrier, his professor said the he was supposed to put forward a feasible idea, and so he gave him a "C" Grade. Perhaps the professor was correct - at the time.

Fedex started in 1973...

Few would have anticipated that something like Startrek's Communicator ( of 1966 +) could ever be nearly universal, affordable and in nearly everyone's pocket.

Just wait for the Startrek Transporter Room ! 2024 ?

[Linktrained]

Some maintenance costs may be cyclical like tyres and U/C. Also engines will tend to last longer if they can be treated gently. (I flew with a Captain who liked to hear his Merlins backfire. He left the Company for another reason.)

A Salty atmosphere may tend to corrode, this is more likely in the bits that are harder to get at. ( During the AirLift salt had to be flown to Berlin in flying-boats, which were designed for salt water.)

Some electrical bits do not like being switched ON. Where possible, leave them ON for the "working day". ( The earliest computers HAD to be left on to get any reliability - and it got hot in the summer, they said !)


Condition Monitoring may be possible, perhaps something like Oil Monitoring, to check the engines for their condition, perhaps giving better warning of impending problems.

[autoflight]

The pointy thing right at the front of the F27 is the radome. Inside is the weather radar antenna. Bearcat, it is time for you to arrange to visit a F27 operator to have a good look at one of their aircraft.

[barit1]

Bear
1) Why do aircraft have dual GPS units?

I did a lot of engine testing, and my boss NEVER liked the idea of two samples of data. "Three is the ideal number", he said.

And transoceanic widebodies of the 70s had 3 INS units - so if any two agreed, the third could be disregarded. But if GPS is sufficiently reliable, two seems a good plan.

[Bearcat F8F]

The pointy thing right at the front of the F27 is the radome. Inside is the weather radar antenna. Bearcat, it is time for you to arrange to visit a F27 operator to have a good look at one of their aircraft.
If there was one within a 20 miles radius I might. Otherwise its a bit overkill as no one expects us to travel distancs just to catch a glimpse of this plane.

I have a more relevant question though. Is the weather radar necessary if the EFB can provide immediate weather information?

[avionimc]

4th year Aeronautical Engineering ...
If there was one within a 20 miles radius I might ...
Is the weather radar necessary if the EFB can provide immediate weather information?
... "radar" I assume you mean wether radar?
Any idea on maintenance costs for a GNS 430W?
why is it occasionally that aircraft are fitted with 2 identical GPS units?
£6594. Sounds pretty expensive
no need for IFR equipment? Just an iPad?
anything I could do with the landing gear to improve DOC?

Indeed, if it is too late for you to change school or vocation, I highly recommend you should consider working as a trainee in a reputable aircraft maintenance shop and learn some basics. As it was suggested earlier, you should also make a point to go to some aviation events such as AeroExpo, AirVenture, Avalon or similar. Even if they are more than 20 miles away.

Spend some time in and around airfields and learn at least something about general aviation, avionics, aircraft systems, etc.

Of course, there has to be DESIRE, without some degree of desire, interest and passion, all is pointless.

Now I better understand why some aviation technocrats, out of so called "aeronautical engineering schools," and end up in SMS, maintenance planning, parts purchasing, audits, etc., are creating so much havoc in the industry and, have no clue whatsoever of what they are doing.

PS. To your latest question if you need a WX radar (vs. EFB or MFD uplink weather only): you should know that the mosaic of data displayed on your MFD is far from being "immediate" as it is obtained and processed from multiple NEXRAD sites, the information could be more then 20 minutes old (cf. NTSB safety alert on limitations of cockpit weather displays).

[Bearcat F8F]

Indeed, if it is too late for you to change school or vocation, I highly recommend you should consider working as a trainee in a reputable aircraft maintenance shop and learn some basics. As it was suggested earlier, you should also make a point to go to some aviation events such as AeroExpo, AirVenture, Avalon or similar. Even if they are more than 20 miles away.

Spend some time in and around airfields and learn at least something about general aviation, avionics, aircraft systems, etc.

Of course, there has to be DESIRE, without some degree of desire, interest and passion, all is pointless.
I have a PPL, I have been in hundreds of airports in multiple countries and I have used a Garmin GPS during an engine emergency. I can assure you I have enough passion for this.

I can also see that you have little understanding of what 4th year of Aeronautical Engineering is like. Can you imagine how much time I would spend traveling to places if I had to do research on the scale you are suggesting for every one of my projects? No, I didn't think so. Perhaps you are unaware of the amount of coursework we need to complete for all of our subjects not including the projects this year. No one expects us to go find actual F27 operators a gazillion miles away. And WRT the general avionics questions that I am asking - an internet forum with people who are in the industry and are willing to help is plenty enough.

Now I better understand why some aviation technocrats, out of so called "aeronautical engineering schools," and end up in SMS, maintenance planning, parts purchasing, audits, etc., are creating so much havoc in the industry and, have no clue whatsoever of what they are doing.
A/C maintenance has little to do with Aeronautical Engineering at university level. We are not learning how to fix planes. We are learning about the principles of aircraft aerodynamics, fluid mechanics, aeroelasticity. The only thing even slightly related to maintenance in our course are the structures lectures but again these are more to do with the physical aspects of materials WRT a/c construction. Furthermore, we have nothing to do with avionics... the "systems" people deal with that.

Why exactly you expected us to come out of the box as being great in any of the disciplines you mentioned above, is beyond me. Perhaps you are confusing what we do and what they do in college? We are not learning to be mechanics, we are learning how to be the spear head for future break throughs in aviation.

So you either want to help or you don't. I have a feeling I have squeezed as much as I could out of this thread. And I have no interest in wasting time here any further.

I appreciate the help that was provided previously and I have taken all of it on board. If someone else could contribute something further, that would be greatly appreciates. Especially in terms of costs associated with maintenance of avionics and GPS systems.

PS. To your latest question if you need a WX radar (vs. EFB or MFD uplink weather only): you should know that the mosaic of data displayed on your MFD is far from being "immediate" as it is obtained and processed from multiple NEXRAD sites, the information could be more then 20 minutes old (cf. NTSB safety alert on limitations of cockpit weather displays).
I "should know" it? OK. I'll take your answer as a "no, you don't need the WX radar as the info displayed is not immediate while the EFB's data link provides accurate real time weather".

Thanks.

[MetoPower]

I have a PPL, I have been in hundreds of airports in multiple countries and I have used a Garmin GPS during an engine emergency. I can assure you I have enough passion for this.

Furthermore, we have nothing to do with avionics... the "systems" people deal with that.

I "should know" it? OK. I'll take your answer as a "no, you don't need the WX radar as the info displayed is not immediate while the EFB's data link provides accurate real time weather".

Thanks.


Bearcat,

With all due respect for the carreer you are about to embrace and the rather unrealistic but challenging project you have been assigned, I am not convinced (yet) of the wx info that could be provided through a datalink/EFB while in the air at up to 25000ft (latest F27 max) if my memory serves me right, while circumnavigating storm cells. One on board Wx radar is a must, two independant is best (and rare).
I remember crossing the Gulf of Guinea at night about 25 years ago at about FL330 and loosing my (still monochromatic Wx radar) while circumnavigating CBs. Had no spare one except the full moon high above.
My only option was to deviate quite a lot to the West and keep it in sight.
ITCZ are quite interresting in this part of the world!
Give me a wx radar (or two)!!

As soon as you have time, make the effort of visiting the end users (ie. airline crew) you will learn a lot and make a very usefull links between theory and practice.

All the best and good luck for you project.

[Bearcat F8F]

Thanks for the suggestion. I have a few friends who are airline pilots or just have an ATPL. I'll ask them as well and see what they say.

As mentioned before, I don't have the luxury of time of going and visiting the end users even if I ever get access to speak to the people I need to speak to - i.e the guys who do the maintenance or maybe the pilots. That's why I am using the forum as the next best thing, if not better. :ok:

[Bearcat F8F]

PS. To your latest question if you need a WX radar (vs. EFB or MFD uplink weather only): you should know that the mosaic of data displayed on your MFD is far from being "immediate" as it is obtained and processed from multiple NEXRAD sites, the information could be more then 20 minutes old (cf. NTSB safety alert on limitations of cockpit weather displays).
I just spoke to a friend of mine who flies 737s and he said what I thought previously: the weather display is real time and not lagging in time like you suggested.

Some of the smaller GA aircraft take wx info from a local station. But I assume the wx radar in the F27 uses radio waves that bounce off moisture and hence gives a real-time picture to the crew.

[autoflight]

http://www.iapgroup.com.au/docs/tech%20services.pdf is a company that upgrades F27 aircraft, including avionics. You could do worse than contact them, explaining your project.

[Brian Abraham]

You could look at what savings can be had replacing the steam gauges in the cockpit with updated systems. The engineers replaced the iron gyros on our fleet with AHRS (Attitude and heading reference system) because of failure rates and attendant maintenance/repair/downtime costs. We already had a glass cockpit, but weight savings can be had by modernising the cockpit. Difficult to quote actual $ savings without having access to substantive figures.

[Bearcat F8F]

(http://www.iapgroup.com.au/docs/tech%20services.pdf)http://www.iapgroup.com.au/docs/tech%20services.pdf is a company that upgrades F27 aircraft, including avionics. You could do worse than contact them, explaining your project.
I will shoot them an email. Thanks :ok:

You could look at what savings can be had replacing the steam gauges in the cockpit with updated systems. The engineers replaced the iron gyros on our fleet with AHRS (Attitude and heading reference system) because of failure rates and attendant maintenance/repair/downtime costs. We already had a glass cockpit, but weight (http://www.pprune.org/newreply.php?do=newreply&p=7687799&noquote=1#) savings can be had by modernising the cockpit. Difficult to quote actual $ savings without having access to substantive figures.
Interesting! Never herd of AHRS before! Will definitely investigate further.