Plastic Pilot

Here are three weather reports (a.k.a. METARs) I got from www.easymetar.com. The first one if from New-York JFK, the second Geneva, and the third from Moscow Domodedovo. They all contain the same information: wind, visibility, clouds, temperature, and pressure. Unless you’re a pilot used to fly on various continents, something should surprise you.

KJFK 291751Z 15013KT 10SM FEW050 SCT100 BKN140 BKN250 28/18 A2982

LSGG 291820Z VRB06KT 9999 FEW050 FEW060TCU FEW070CB 29/15 Q1017 NOSIG

UUDD 291800Z 24002MPS 6000 BKN023CB BKN100 14/14 Q1004 TEMPO TSRA

Winds for New-York and Geneva are given in knots (KT), but Moscow ones are in meters per second (MPS). Good pilots know that 1 meter per second is 1.94 knots… pragmatic pilots call that 2. The other look in Google.

Then come the visibility. 10 Statute Miles (SM) in New-York, 9999 meters (10 km or more) in Geneva, and 6000 meters in Moscow. Funny to see that wind New-York is given in Nautical Miles per hour (knots), and visibility in Status Miles. And what about Geneva ? Wind in knots, visibility in meters. One must give that to the Russians, they’re more coherent: both wind speed and visibility are given in meters.

But when it comes to clouds cover… all three airports report them in feet ! Brilliant harmony, but not for long. The New-York air-pressure (QNH) is given in inches of mercury, whereas both Geneva and Moscow report it in millibars.

This simple example is just scratch on the surface of the units chaos that exist in aviation. Airspeed indicators can be graduated in knots, MPH, or kilometers per hour. Depending which manufacturer publish them, weight and balance sheets can be in kilograms or pounds. Fuel can be delivered in liters or US gallons. For larger aircrafts, it comes in tons or pounds. Oil comes in liters, or US gallon quarters.

Take-off and landing performance calculations can be critical. The tools (tables or graphs) used to determine the required distance for taking-off or landing produce results in meters… or in feet.

When it comes to flying, the things could also get complex. In Russia, altitudes in clearances are given in meters. Jeppesen publishes charts with values in feet, with conversion tables. A typical Moscow departure initial climb clereance is 3550 feet, corresponding to 900 meters.

How safe is such a unit mixture ? For a crew operating under normal conditions, this requires some additional attention. Put some extra-pressure (bad weather, technical problem, may be an emergency), and this is one more possible trap. Units problems were a contributing factor in several accidents, including the infamous Gimli Glider - a 767 that ran out of fuel at 41′000 feet, partly because of a metric units problem.

The problem is clear, so what about the solution ? Glass cockpit systems can switch between various units, reducing the number of calculations to be made by the crew. This is a good step, but not yet a full solution. So here comes the quesiton again: should aviation switch to the metric system ?

This switch would impact an incredible number of areas. On aircraft side, it means avionics upgrade, fuel system upgrade, new weight and balance documents, updates to the aircraft manuals, and probably pilot training. On ground, ATC systems shall be adapted to display speeds, altitudes, winds, pressures in metric units. Controllers shall be trained to new procedures with metric values. Maintenance engineers, fuel and dispatch staff shall also be familiarized with the new units systems.

The cost of such a switch would be simply huge. The next problem is to manage the transition. The whole aviation system could not be adapted overnight. Handling that mixed situation safely would not be an easy thing. How many Gimli-glider-like accidents could this change create before all crews get used to the new system ?

To me, it all boils down to two questions:

• Will airlines pay for this change ?
• Is the solution more hazardous than the problem ?

My crystal ball is undergoing maintenance right now, so I can’t answer those questions. If yours is working, I’d be glad to know your predictions.

PS: Many thanks to Paul from www.askacfi.com, who asked this question in a comment on his own blog.

London City Airport is on the list of my aviation projects and dreams. I love this airport, because of its a time saver, because it has a unique implantation, and because of the unique scenery it offers. However, this is for me kind of a Forbidden Land, because of all the constraints.

No private pilot can land there. No single engine (even single engine turbine) can land there. No private traffic can use this airport. All pilots operating there need to go through a special training. As I don’t want a job as professional turbine pilot, the chances for me to land there otherwise than as an airline passengers are low, if not inexistant. By the way, if you’re working for BAA / CAA and can arrange an exception (even a single ILS approach with go-around will do), or for an operator and can arrange a jumpseat flight, you’re welcome.

Before someone makes it possible for me to go there, here are some pictures, found on airliners.net. Click on them to see the full size version on airliners.net.

On this first photo, taken on final 28 on the glide path - it seems high, but look at the PAPI - one can see the construction works left of threshold. Note that the only possible way for departing aircraft is to backtrack ruwnay, and this seriously reduces the airport capacity.

The second photo, taken in 2008, shows the reason for these works: a partial parallel taxiway has been built. It is still necessary to back-track, but two planes can depart rather quickly one behind the other, and that shortly after a landing, making the runway capacity higher.

Finally, a photo taken on final for runway 10. It was also taken before the construction of the floating taxiway. The approach angle is also impressive, but the departure (go-around) path is much clearer than on runway 28…

PS: simple visit of the tower would be fine as well

Here we go again - 7 links to various aviation related resources on the web. Don’t stop before the end, or jump directly to the last one…

The blog of Eddie - Pilot in training
Eddie’s blog is rather new, and is one more instance of a dreamed I personally missed: blogging the process of becoming a private pilot. These days are well behind me, but Eddie is right in that now !

Most dangerous airports
I guess all is in the title. A classical theme, but well documented. Photos from St-Marteen, but also a video of the KLM 747 landing there. Courchevel is also part of it, with both photos and videos. There are also a couple of one I did not know, so a good variation on a known theme.

The bigger lego plane in the world
What can you do with 75′000 lego bricks (100 kgs), within 600 hours ? A Sinapore Airlines Airbus 380. Don’t ask.

Newlyweds fly to the reception
I took my introductory flight the day before getting married, and was 22. Rob Hoschner, 22, and Rachel MacKay, 23, made much better: together with their families, they flew from church to their private hangar, where the reception was held. That’s so romantic.

Jetwhine asking where is the best aviation blog
If you like to read aviation blog (apparently you do…) you probably know Jetwhine. They recently asked where is the best aviation blog, so many readers submitted their favorite blogs, thus creating a wonderful directory. Special thanks to Jess Sightler, who kindly submitted PlasticPilot.net.

Operation Pegasus - DA42 airborne for 13 hours
It was probably not a flight at full power, and flying for more than 10 hours in a light aircraft is not an uncommon thing (how do you guess we bring them from US to Europe ?), but it usually involves extra tanks. This DA42 flew for 13 hours non-stop using the standard tanks, and landed with legal reserves.

Surprise, surprise
This is not exactly aviation related, but has something to do with flying. When I saw that, I could not resist to publish this link. I look forward to have your opinion: post-production special effects, or real thing.

Read older “Best of the aviation web” posts in The Archives.