Precision Simulator update 10.167 (12 March 2023) is now available.
Navburo update 13 (23 November 2022) is now available.
NG FMC and More is released.

Main Menu

General 747 event, not from avHerald

Started by simonijs, Fri, 13 Jan 2023 12:40


Well, general...! According to this Dutch website (in Dutch language), KLM-Martinair Cargo PH-MPS (747-400BCF) landed very hard in Miami on December 22nd (at 1808z), causing serious structural damage to wings and flaps.

Some sources say: "damage (to flaps) may be beyond repair", the airline states they are investigating possibilities to repair, that may be completed not before January 20.

202212221853 METAR KMIA 221853Z 26009KT 10SM FEW023 SCT040 SCT250 29/19 A2995 RMK AO2 SLP141 T02940189=
202212221753 METAR KMIA 221753Z 22007KT 10SM SCT023 SCT038 SCT250 29/20 A2997 RMK AO2 SLP150 T02890200 10294 20217 58024=
202212221653 METAR KMIA 221653Z 19008KT 10SM SCT035 SCT250 28/20 A3000 RMK AO2 SLP160 T02830200=

Another aircraft (PH-CKC - 747-400ERF) landed in Miami on November 3rd only to leave Miami on November 18th. I found no reports on this particular flight but two weeks on the ground is some serious AOG.

Both aircraft were flying scheduled service MP6141...




That's a seriously hard landing. Boeing did some research with accelerometers scattered around various points on an aircraft, and they determined that there is no simple solution to determining via instrumentation whether an aircraft landed hard.

From Boeing: "Using vertical acceleration values as the sole criterion for initiating unscheduled inspections is generally not advisable because of the location and design considerations of the FDRs and accelerometers. In most instances, there is no absolute way of knowing whether the recorded accelerations are a minimum, maximum, or some intermediate value relative to the entire airframe structure. This is because the onboard accelerometer located near the airplane CG is limited in its capability to capture actual loads that may be occurring in the entire airplane structure during the landing impact. Several accelerometers placed throughout the airplane have shown significant variations in both time and magnitude of vertical acceleration values, or structural loads. These variations are the result of airplane weight, CG, motion (e.g., sink rate; forward and side velocity; roll, pitch, and yaw angles; and corresponding rates), external forces (e.g., gust loads, ground effect, and runway contact loads), and structural dynamics (e.g., vibrations and harmonics). Also the sampling frequency of the recorded vertical acceleration data — which is subject to the specific flight recorder installation and varies from 4, 8, or 16 samples per second — can cause wide variation in recorded peak vertical acceleration values."

Because of this, the most reliable indicator of a hard landing is flight crew judgment.

Per Boeing: "Past experience also indicates that the flight crew's determination of a hard landing is the most reliable criterion because of the difficulty in interpreting recorded acceleration values at the CG of the airplane."

Which makes me wonder what the flight crew said about the landing in this report...

"Ummm, Jim, that one was pretty hard."
"Yep, I bet we broke the flaps."
Will /Chicago /USA

Jeroen Hoppenbrouwers

Probably something like:

"Durf jij hiermee terug te vliegen?"
"Ikke nie. Jij wel?"
"Oké dan. Jij schrijft?"

Hardy Heinlin

What kind of flap damage could that be?

Jeroen Hoppenbrouwers

Just guessing: rollers broken off the flap tracks, tears in the flap surface just next to the attachment points, bent tracks, bent flaps, ... Those things are pretty heavy and will sway nicely under sudden G-load.


"Ehmm, Jan, die was behoorlijk slecht."
"Ja, ik wed dat we de flappen hebben gebroken."

Courtesy of Google translate....
Will /Chicago /USA


She is flying again, so not a write-off. Just took off from Miami...

Jeroen Hoppenbrouwers

... heading to Quito, not to the desert ... relevant detail ...


I hope Hardy is asking about the damage to get some more hard landing damage in there if it's even possible to simulate! As always thanks to all of you pilots and Hardy that ensure PSX is the best it can be. I first owned PS1 in 2001 as a 14 year old with ambitions and at the time the resources available to become, or at least try to get my commercial/ATP. In 2007 I found out that my eyesight is shockingly poor and have a problem where I have mini cataracts that haven't joined which leaves me with a lot of floaters in my eyes. I'm now 35 and this brilliant app gives me a sort of freedom and comfort in that I'll never fly a big jet. But I've got a 747 inside my PC, which surpasses all other software I've purchased to fill the void, and believe me it was a lot, before I finally decided to save for a few months a few years ago to get PSX. I remember I used to write on the old forums in 2001 sometimes and Jeroen is the one other user along with Hardy that I remember. I remember that my joystick wasn't syncing properly with the MSDOS based software at the time! I think it was the throttles that wouldn't connect. Sorry this is a little verbose and off topic but it's just a thank you message to everybody on here and Hardy. I don't write often, but I'm always reading. Wish you all well!

Jeroen Hoppenbrouwers




Age is relative! I have never asked despite knowing who you are all these years; what you do as a job, I see you wrote avionic equipment design, but you've been here a while grandad ;-D (only joking) Although you have been a consistent supporter of Hardy's products from as early as I can remember since joining the forum which must have been early 2000). I got PS1 after begging my family when I was 13 to pool their gift money together so my uncle down in Brighton UK could go to a town called shoreham with an airfieldand a aviation shop (Transair) to pick up a PS1 copy for me. That's the extent I went to to get this! All the best!

Jeroen Hoppenbrouwers

Well, the story is kind of funny.

I got PS1 for DOS because I wanted an air traffic control simulator and that one turned out to be only for Win95 which I didn't have due to lack of powerful hardware (yes). So I got the next box in the online shop because it also had an ATC robot etc. etc. etc. bad excuse etc.

Before long I started to write additional software for PS1, attempting to connect it to VATSIM (was then still SATCO) which caused the first appearance of what is now the network link, and then I wanted ACARS, so I built ACARS, and that needed a controllable MCDU, so I built that, and ... and ... and ...

And then people out on the internet started asking me whether I could interface all that kit to bigger simulators, and then even bigger simulators, and then to a real aircraft. By 2010 I was turning my attention towards avionics more and more, as that was where I wanted to be since I was about 12, but never really got the chance. And eventually I got that chance, moved to Miami, and have been designing (and building and testing and certifying) Iridium SATCOM gear and quick access recorders etc. for Big Airliners since 2011.

So it's all Hardy's fault, but we all know that.

Well, Matt also has a lot of blame to carry here.

My current boss likes to tell the following story to visitors.

2003: Hoppie travels to Sydney, gets a United flight ops manual handed and builds the ACARS part of it for Matt's simulator.
2012: Hoppie travels to Chicago to finalize the installation of his brand-new SATCOM into a United 747-400 (N194UA).
2013: Matt sends Hoppie an update of the flight manual so Hoppie can update the sim.
Hoppie points out that he cannot update the sim because the update is his own code and the sim already has that.
2015: Matt buys the flight deck of N193UA and starts shipping it to Sydney.

It's not entirely accurate I bet, but it makes for a good story.



While on the topic, I hope I can bug you with some (hopefully not too dumb) SATCOM related questions.

How does the Beam Steering Unit know where to look for a satellite? Does the SATCOM have a database of the current constellation it is using similar to the GPS almanac? If so how often is it updated?

I see in our fleet listing that each aircraft has one or more +870 numbers. Could you call these from any network's landline/mobile phone and ping the call light on the audio panel? Also would Air-to-air calling work in this way?

I'm guessing you couldn't navigate a DTMF menu if you called up and wanted to order pizza at your arrival station hotel.  :D

Jeroen Hoppenbrouwers

Quote from: Owl on Fri, 27 Jan 2023 14:34How does the Beam Steering Unit know where to look for a satellite? Does the SATCOM have a database of the current constellation it is using similar to the GPS almanac? If so how often is it updated?
It depends on the satellite constellation.

For Iridium, with 66 LEO satellites that give you a constantly changing situation (, the original system worked just like a cell phone. Your cell phone does not know about towers or transmitters. It just listens to the whole band and picks out the strongest signal. Iridium does the same, with a simple omnidirectional antenna.

When Iridium then went NEXT ("Certus") they wanted higher bit rates, for which they required beam steering antennas to some degree. You can either have a small number of moderately directive antennas, all pointing in different directions, and select the one that has the loudest signal; or you can construct a true beam steering device (usually nowadays by phased array technology). Since the constellation is so dynamic, these things don't use any kind of almanac but just scan until they find where the signal comes from and then keep adjusting. Every nine minutes they need to swap from one satellite to the next, which is physically impossible in zero time, so usually these things employ two beam steering units in some way. It's definitely not easy, one of the reasons why the Certus systems are so slow to appear for aviation.

Inmarsat uses geostationary satellites and that's a lot easier. Each satellite has a fixed position so you combine your IRS position with the airplane heading and attitude and the satellite's position and hey presto, aim there. Once you find the satellite, you usually use the IRS for turn prediction but also keep dithering a bit around where you calculated the satellite is to find the exact best direction. For GEO, you need to point a whole lot better than for LEO, of course. The database changes ever few years as Inmarsat commissions and decommissions satellites. It's a never ending hassle.

QuoteI see in our fleet listing that each aircraft has one or more +870 numbers. Could you call these from any network's landline/mobile phone and ping the call light on the audio panel? Also would Air-to-air calling work in this way?
It used to for older systems and it may still work this way for later ones. But the SATVOICE standard uses a separate phone system, not the public switched telephone network. Either you lease a line into this ATS system, or you beep-beep-beep yourself in for each phone call. The aircraft of course are already on this network. Typically ground stations have their own login and PIN and there are various call priorities that determine who gets kicked off the satellite in case of congestion. Look on oceanic charts -- the FIRs have 6-figure short codes that are known to the ATS network and function as their phone numbers. Airplanes have as ATS phone number their ICAO transponder mode S code converted to octal.

QuoteI'm guessing you couldn't navigate a DTMF menu if you called up and wanted to order pizza at your arrival station hotel.  :D
Actually some airlines have a dispatch/crew roster phone system that requires DTMF beep-beep-beep and they use hand-held microphones with a DTMF keyboard! This does not work for all possible systems, of course. Not all codecs can transfer the DTMF tones reliably and accurately, and some SATCOM systems listen to them which defies the purpose.


DTMF mike at the left. Yes this is N194UA! June 13, 2012, KORD.


That's a brilliant story Jeroen! I have never heard of Satcom, although in 1999 I was 12 years old; I do remember trying  'roger wilco' I'm sure that's the name of it, it was sort of like the teamspeak for MSFS98/2000 etc. I didn't realise quite how much you've contributed! The only annoyance is that I never did manage to get my joystick working with ps1 properly! I always had an MS sidewinder (nor pro) at the time, but can't remember if it was the whole unit that I couldn't get working or if it was just the throttles or rudder controls. I was using Windows Millenium Edition when I got PSX, I got both on the same day in December 2001! It's Great to be back :)