Tag Archives: C-130


Some of you may have wondered why all aircraft windows and so many other parts in the pictures I showed in previous blog posts about The Boneyard are covered with white paint?

C-130 Hercules covered with spraylat (note that it is fitted with skis for Artic and Antartic operations).

C-130 Hercules covered with spraylat (note that it is fitted with skis for Arctic and Antarctic operations).

To protect heat-sensitive parts from the desert high temperatures these parts are covered with two different coatings: the first layer being a dark paint while the second layer is the characteristic white one, reflecting sunlight and heat. The paint is a vinyl plastic called spraylat after the company that produces it, Spraylat Corporation.

You may check the detail of Aerospace Maintenance and Regeneration Group (AMARG) storage processes in the following two links from the Wikipedia and “AMARC experience” (“AMARC” being the previous name for AMARG).

Leave a comment

Filed under Aerospace & Defence

The Boneyard

The US Air Force’s 309th Aerospace Maintenance and Regeneration Group (AMARG), known as “The Boneyard”, is one of the places that I had wanted to visit since many years ago. Luca and I visited it a couple of weeks ago.

The Boneyard is an aircraft and equipment storage facility located at Davis-Monthan AF Base near Tucson (Arizona). The are over 4,000 military aircraft stored at the place. Most of them come from the USA (not only from the air force, but from other services as well) but there are some aircraft from foreign countries. The aircraft are stored for several reasons and in different conditions.

  • Some of them are maintained waiting for a possible future use of them (be it with US armed forces or through some foreign military sale, that is the case of several old versions of C-130, F-16).
  • Other aircraft are kept so their parts can be used as spare parts for other active flying aircraft (e.g. C-130, KC-135).
  • Finally, there are aircraft which are stored waiting to be scrapped so the metal can be reused somewhere else.
KC-135 partly scrapped.

KC-135 partly scrapped.

Hundreds of C-130.

Hundreds of C-130.

There are whole fleets of retired aircraft: C-141 Starlifter (retired once the C-17 took over their role), half of the C-5 Galaxy fleet (the A versions, due to budget constrains and fleet strategic decisions), the Vietnam-era helicopters Hueys and Cobras

The Boneyard can be visited with a guided tour organised by the Pima Air and Space Museum (I will write about this museum in another post).  The tour is made with a bus which goes through the Boneyard very slowly and making several stops (though guests cannot exit the bus). The guides are veterans from the US armed forces, who have flown or maintained some of those models that you get to see. The wealth of knowledge that they have about them, the anecdotes and stories that they tell during the tour are worth much more than the 7$ that the tour costs.

The place is impressive, overwhelming. Not only there are thousands of aircraft but the seeing of them fully aligned, whole fleets of different models helps you put things into perspective:

  • World commercial airliner fleet (over 100 pax) has about 16,000 aircraft vs. the 4,000 at The Boneyard.
  • The largest airline fleets have about 1,200 aircraft.
  • Spanish AF has 14 C-130 Hercules vs. the hundreds of them you see at The Boneyard.
  • The dozens of retired Lockheed C-5A Galaxy that you can see there have a combined payload capacity of over 5,000 tonnes… which is more than the complete payload capability of any other air force in the world except the US one…

You may want to take a look at satellite images from the Boneyard here:


Filed under Aerospace & Defence, Travelling

Quiz: How loaded do US Air Force transport aircraft operate?

Let me share with you one funny quiz I did for some colleagues at the office:

On average, how loaded do US Air Force transport aircraft, C-130 Hercules and C-17 Globemaster, operate? (as a percentage of their maximum payload capacity: let’s take the figures reported by the US Air Force, ~16.5 tonnes for the C-130 -“maximum normal payload”-and 77.5 tonnes for the C-17)

Before continuing reading below, take your chance in the poll below, where I offer 4 possible responses: 3 from my colleagues’ responses to the quiz plus the correct one:

Background. Before posing the quiz to my colleagues we were commenting on a piece of news of an Antonov 124 which had landed in Spain to load some equipment weighing 1,000 kg. The An-124 reported payload capacity is 150 metric tonnes. For those not being number-crunchers: that means using the one of the biggest cargo aircraft to load it up to 0.7% of its capacity.

After having read this last paragraph you may have changed your opinion as to which is the correct answer to the quiz.

I based the correct result on a news release from the US Air Force dating from the beginning of 2007. At that time I was working in Airbus Military strategy where I would like to pick up any number related to aircraft and play with it (the hobby has stayed). That release offered figures US Central Command air transport operations, including operations Enduring Freedom (Afghanistan) and Iraqi Freedom. Find the results from that short number play:

US Air Force average loads (in tonnes) for C-130 and C-17 during 2005 and 2006.

US Air Force average loads (in tonnes) for C-130 and C-17 during 2005 and 2006.

If you do the math, you will immediately get the right answer: C-130 Hercules, 22% and C-17 Globemaster, 17%.

“What a waste of resources!” you may think. A former senior colleague pointed to that result: “You buy a Mercedes to travel with the family and baggage, then on a Sunday when having to go out to get some bread or any week day when you go alone to work… when you get to the garage and find a Mercedes… Guess which car you take?”

1 Comment

Filed under Aerospace & Defence


Since some time ago I wanted to write a small entry just to show the following graphic to point a very basic issue to non-engineers:

Efficiency vs. airspeed.

I have very often heard remarks about turbo propellers referring them as old or old technology, etc. I guess that this comes from seeing images of old aircraft with propellers and reciprocating engines, and now people being used to fly in turbofan engines.

However, turbo propellers are neither old nor a worse technology. As almost everything in engineering it all depends on what the requirements are and the price to pay for the solution. Then come the trade-offs. As you may find in the Wikipedia entry [turboprops] “they are mostly used where high-performance short-takeoff and landing (STOL) capability and efficiency at modest flight speeds are required”.

The first requirement is among the ones explaining why some military transport aircraft such as the C-295, the C-130 or the most modern A400M are equipped with turboprops.

The second requirement explains why some regional airlines employ turboprops for short-haul flights, when the distance can be covered at a bit lower speed without a big impact in the flight time.

If you take a look at the picture above, you could start roughly guessing what type of engine you would choose depending at what speed you would normally fly (then more requirements would come into play).

Leave a comment

Filed under Aerospace & Defence

An aircraft worth its weight in gold?

Airbus announced last January that it had raised the list prices of its commercial aircraft by an average of 5.8%. It had not updated its prices since 2008. You may see the current prices here: Airbus list prices

Boeing also discloses in its website the range of list prices of its aircraft. Those prices haven’t been increased in the last two years.  

Few years ago, I saw for the first time a comparison of prices of aircraft per kilogram. It was prepared by a teacher I had at EOI Business School in Seville, Felipe Moran, who later has become a co-worker. With this post I will start a series of comparisons, the first one being precisely that one: an update on price per kilogram of aircraft. 

We already saw where to get the prices from. The other input we are going to use is the weight of the aircraft, what is called: Operating Empty Weight (OEW). You may find this information in various places, I recommend you to pay a visit to Boeing’s “Airplane Characteristics for Airport Planning”, where you will find very detailed data of all its commercial aircraft.  (While gathering this info I also came across the following section dedicated to fun facts of the legendary Jumbo 747).  

Combining these inputs we can build the following table. 

Price per kg of commercial aircraft.

Some facts may counter intuition: 

  • There doesn’t seem to be a clear discrimination between older and newer aircraft (A380 and some 787 models rank among cheapest, while A350-900 and 787-9 are among the most expensive).
  • Smaller Airbuses rank among the most expensive aircraft in a per kg basis despite the suggested price war that was reported by the specialized press in the recent years.

With the exceptions of A350-900 and 787-9 there seems to be a very slight trend in bigger aircraft being cheaper in this per kg basis. One may argue that once the frame of a certain size is built, building a bigger one might not cost that much

Now, let’s talk about the Military Transport business. Do we think those aircraft are more or less expensive? On one hand, those aircraft are not carrying systems such as the in-flight entertainment and, on the other, the scale of the market is smaller (with few exceptions such as the C-130) and they do carry diverse military systems, protections, etc. What is the trend weighting more in the balance? 

Military transport aircraft price per kg.

As you can see, military transport aircraft are on average 25% more expensive on a per kg basis. There is much more technology in them than people tends to think… they are clearly not just flying trucks. 

As you may have noted I have not included any sources for the prices of these aircraft, since they are rarely disclosed. I have used prices reported by the press and US budgets. 

Let’s stretch the argument a bit more… What is the trend for fighter aircraft? This time scales are bigger than in military transport. Does this make them cheaper? See the table. 

Fighter aircraft price per kg.

Not even close. Fighters are around 3.2 and 4 times more expensive than military transport and commercial aircraft, respectively, on a per kg basis.  

We can see in the following graphic all these aircraft together and maybe spot those trends. 

Aircraft prices per kg.

Now that we have an idea of how much aircraft cost per kg (1,700$ commercial aircraft, 2,100$ military transport aircraft and 6,700$ fighter aircraft)… is this expensive? Expensive compare to what? 

Let’s relate these prices to something closer to us. 


  • The best-selling car in Spain in 2009, was the Renault Megane (with 52,156 cars sold). It costs about 17,700 € (or 24 k$) and weighs 1,150 kg, this yields: 21 $/kg, clearly cheaper, about 80 times cheaper than commercial aircraft on a per kg basis. 
  • More up-scale cars such as the Mercedes Class E 350 CDI (56,000€ and 1,825 kg) or the Audi Q7 4.2 TDI (85,000€ and 2,605 kg) are more expensive per kg, 41$/kg and 44 $/kg, respectively. This is 40 times cheaper than commercial aircraft.

It may be worthy to note that in the cars we see the completely opposite trend than that we saw in airplanes: the bigger the car the more expensive on a per kg basis. 

Let’s compare this yet again with some other unrelated luxury item: Jamón Ibérico Puro de Bellota de Jabugo 5J. Today it was on offer in El Corte Ingles website for only 449€, a piece of about 7 kg, yielding: 87 $/kg. This is twice more expensive than buying a Mercedes (this may be the reason why it was an offer from Sanchez Romero supermarkets) but still 20 times cheaper than a commercial airliner. 

To end this post, let’s answer the question posed in the title of the post: 

The kilogram of gold is in the order of 35,400$, clearly more expensive than any aircraft. 

After all, nowadays, we may find no aircraft worth its weight in gold.


Filed under Aerospace & Defence