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WTF? → OK let’s do this
So the other day I was rudely separated from my audience by
world events no recent developments no. Forget it.
Anyway, the point is that I’ve been doing this explaining thing for a long time now and posting about it somewhere online instead of on my whiteboard in a classroom could be what I need.
Do you need it? Who knows. Will it be useful? Possibly.
I’m going to start with ADS-B.
If you like this or want to encourage me leave a comment here.
The web is more than just fb and insta can you believe it ;).
Not enough aircraft will be equipped at the original deadline
In an interesting but not unexpected move last week (april 22, 2020) the European Commission and EASA published an amendment to Implementing Regulation EU No 1207/2011 that effectively delays the mandatory retrofit of aircraft with ADS-B to 2023. It turns out that not enough aircraft are expected to be equipped by the deadline.
The original plan was like this:
Every aircraft that is flying IFR faster than 250kts or that is heavier than 5700kg must have at least ADS-B out
Implementing Regulation EU No 1207/2011amended by EU No 1028/2014 and EU 2017/386
Surveillance Performance and Interoperability Implementing Rule, SPI-IR
As you can see the original deadlines of 2015 and 2017 had already been moved to 2020.
So why was that and why now again?
Have a look at the numbers
It is really quite simple: in June 2020 only about 74% will be equipped. If nothing happens the rest will be grounded. Who is the rest?
Aircraft that have problems with the deadline
Some of these aircraft only just got a certified ADS-B solution, others never will and some will be retired. For most it is a combination of cost and availability of equipment and hangar space.
Delays and exemptions are now possible
The EU came with the following solution to cater for this:
- A permanent exemption for historic (or just old) aircraft.
- An exemption for aircraft that are about to be decommissioned.
- Under certain conditions more time for aircraft with an airworthiness certificate from between 1995 and DEC 2020. All the way up to 7 JUN 2023.
- New aircraft with a certificate of airworthiness on or after 7 DEC 2020 must comply.
See also source at ads-b-europe.eu
Well it’s not exactly brain surgery, is it.
But do check out this short clip.
Dusting off the FAA takeoff safety training aid
I teach Aircraft Performance for commercial pilots (ATPL) and the question that ALWAYS comes when we talk about V1 is:
- What if something happens after V1 and the runway is long enough to stop on?
The simple answer is: You fly.
The catch is: What if you think the aircraft can not fly? How do you know if you are right?
Thanks to a report by the Dutch Aerospace laboratory NLR this matter has new fuel in the form of statistical data and a long forgotten safety program.
High speed abort: faster than 80 knots
After call “80” at 80 knots, the takeoff is only aborted for serious events such as engine failure, engine fire, directional controls or an obstructed runway. Some operators choose 70 or even 100 knots but most use 80. This is also because most modern airplanes have a flight phase inhibit for certain warnings at that speed up to 1500 feet AGL.
V1 is usually higher than 80 kts. A typical value for a Challenger 350 is between 119 and 130 kts. Then there is also reaction time:
With a typical acceleration of 3 to 6 knots per second, just 3 seconds for assessing the situation and decision-making, will add 9 to 18 knots to the speed. If the aircraft is close to V1, it now most likely has exceeded it.NLR-TP-2010-177
For this report a dataset of 135 high speed aborts was analyzed. There are some interesting numbers in there:
In more than 80% of the high speed aborts, the decision was made after V1
- In 90% of these cases the aircraft could not be stopped on the runway.
- In about half of those cases, the decision to abort was correct or unknown
Only 20 to 25% of all rejected takeoffs are caused by engine failure.
The other 75% by something else.
The Takeoff Safety Training Aid
An old FAA training tool exists, called “The Takeoff Safety Training Aid.” The program consists of a detailed article with the title “Pilot Guide to Takeoff Safety” and a movie: “Rejected Takeoff and the Go/No Go Decision”
The movie looks like a VHS-style movie from the previous century (because it is) and can be found on Youtube:
The full description of the Takeoff Safety Training Aid can it be found under this link.
Has the question been solved: What if there is enough runway after V1?
Well, how do you know if it is enough? And also, how do you know if the failure prohibits the aircraft from flying?
There are plenty of cases where the late decision ended badly:
Runway Overrun During Rejected Takeoff in Bedford, MA 5/31/14
Bizarre stuff, good material for lessons on the importance of sop’s.
Ilyushin IL-18 Aborted take off
Runway overrun after rejected take-off, MD-88, Groningen Airport Eelde
On the runway checks were performed. FDR data indicated a stabilizer position change from 6.8 to 7.2 degrees aircraft nose up (ANU). Thereafter the crew initiated a static engine spin-up. Again the stabilizer warning sounded. The crew released the brakes and started the take-off roll. From the CVR it is derived that during the entire take-off roll the warning sounded continuously.https://https://www.onderzoeksraad.nl/en/page/750/runway-overrun-after-rejected-take-off-md-88-groningen-airport-eelde
When attempting to rotate the captain experienced a heavy elevator control force. The captain stated that he needed much more than normal back pressure on his control column to lift the nose. He felt ”it was impossible to make the take-off”, and as the nose did not rise he decided to reject the take-off. Post accident analysis revealed that the rejection was initiated at 128 knots.
I guess it remains a problem. Apart from some of the strange decisions above, the only time where it is actually very clear that you can and must stop after V1 is in the sim on a 4 km runway where at Vr you feel that the elevator has “mysteriously” become jammed so you stop on the remaining 3 km of runway….
It isn’t always that obvious:
- UPS MD11 at Seoul on Jun 6th 2016, rejected takeoff, runway overrun results in nose gear collapse
- Air Berlin B738 at Dortmund on Jan 3rd 2010, rejected takeoff results in runway overrun
But sometimes regrettably also very catastrophic
Learjet 60 runway overrun, Columbia Metropolitan Airport, SC (CAE) Friday 19 September 2008
According to the report it is a about a 50/50 choice:
Many high speed rejected takeoffs (44%) should not have been conducted. This number is only slightly less than before the introduction of the training aid (51%); Pilots have difficulties in recognising “unsafe to fly” conditions.
Records are breaking
July 25, 2019
It is high summer in Europe with record-breaking temperatures (again) today.
Also we are seeing record-breaking ranges on LORA trackers.
This is one of my gps-nodes on the Things network that rides along in a delivery truck.
It passes the dike between Enkhuizen and Lelystad often but it never had any coverage on it, until today.
180 km to Middelburg
As a comparison, here is a typical day:
It passed the same road and was only picked up by the gateway in Dronten well after passing Lelystad.
It gets crazier
I was investigating the traffic to my gateway and found a blip from an unusual distance. After following it back to the source I found this:
So what causes this? Is LORA dx-ing today and bouncing of a freak layer that only exists on very hot days? Is it maybe a special pressure system?
Crunching pressure systems?
The pressure is only 1014 hPa, just 1 hPa above standard 1013. Could it be because of that crunch zone we are in between the low pressure to the west of Ireland and the high to the east, the same one that is working as a gear wheel to transport all that hot air our way?
Bouncing on the bottom of an inversion
Is there maybe a massive temperature inversion that causes tropospheric propagation or even tropospheric ducting?
The observable characteristics of such high-pressure systems are usually clear, cloudless days with little or no wind. At sunset the upper air cools, as does the surface temperature, but at different rates. This produces a boundary or temperature gradient, which allows an inversionlevel to form – a similar effect occurs at sunrise. The inversion is capable of allowing very high frequency (VHF) and UHF signal propagation well beyond the normal radio horizon distance.https://en.wikipedia.org/wiki/Tropospheric_propagation
There is a temperature inversion below 1500 feet, but it is now very powerful.
Look what it says on this report by KNMI:
FBNL50 EHDB 250818 WEERBULLETIN VOOR DE LUCHTVAART . GELDIG 250900/251500 UTC HOOGTEWINDEN EN TEMPERATUREN: 09 UTC: 15 UTC: 0500VT 120/05 +28 140/10 +36 1500VT 100/10 +30 140/10 +33 3000VT 100/10 +27 170/10 +29 FL 050 180/05 +22 200/15 +23 FL 100 230/10 +08 200/10 +09
It seems that this could be enough though because at the moment it is the only way that I can explain how an 868 MHz UHF signal can do dx. The inversion is gone 15 UTC so if that is the cause of the dx then we can expect the conditions to disappear as the day progresses.
Looks like a reasonable explanation. If someone has a better understanding of this then I’m open to input. Temperatures are rising fast now so I’m going to find a place somewhat cooler.
There is no cloud, it’s just someone else’s computer
This catchphrase is becoming more popular lately. Why? Because it’s not just about storing your data in Dropbox, or handing over all your images to Google for the convenience of it.
Need I still remind you of this and this?
People are returning to personal websites and private servers for several reasons. Let me give you a few:
Facebook decides what you need to see and when. Instagram same thing. Twitter now has a feature where you can undo this but that setting magically flips back after a while.
The sprinkler system
What if Facebook or Youtube or wherever you are currently putting your stuff suddenly decide that you violate their terms of service or simply change their mind and delete your account (ok well, set it to invisible).
My favorite podcasters have this to say about it:
If you build your business on someone else’s lawn, don’t be surprised if they turn on the sprinklersThe grumpy old geeks
Go check them out here.
Works with Nest – not
…. as a service. Until you stop paying the subscription, the service changes it’s mission or just disappears.
So I have this blog here that nobody reads or cares about but at least I can find my own stuff back and I know that if I don’t suffer another server crash or get fed up and delete it again, it will still be present and in the same place where I put it.
See you later 🙂
Here’s an interesting video that was brought to my attention today by a Captain from India.
On Feb 16th 2017, Jet Airways’ flight 9W-118 from Mumbai (India) to London Heathrow failed to make contact with German ATC after being handed over from Bratislava. The aircraft was finally intercepted in German airspace near Cologne at FL360.
The best part about this video is the excellent quality of the footage that was filmed from an other airliner on the same track at a higher level.
Read the full factual description of this incident at the Aviation Herald.