1078kph in 737-800 - mach 0.xx?

[Aronn]

Hello =)

A month ago or so I was on a 'yet another' flight with Ryanair (one out of 12 of them so far this year for me). Long story short, the departure airport got fogged down, aircraft diverted and pax (14 including me!) got bussed to a/c. 3 hours later we took off. ENTO -> EDDW. I guess the pilots had been told to hurry up and make in some time, as they were heauling some serious a**.

At some point during the flight the pilot announced that we were doing a steady groundspeed of 1078kph (or 582kts or ~670mph), OAT -50°C. Altitude I cant remember. There was also something about getting there ASAP, buckling up and holding onto sth..

I was unable to confirm speed with my GPS as it was out of battery.

Anyway, the flight was - as one can imagine - rather shaky and bouncy and the wings were doing some serious flapping with the engines bouncing opposite of the wings to add to the view out the window. Quite the show. Whatever the actual speed(mach) was, it was faster than the aircraft would like to go. It did not feel anything like turbulence, which we encouter quite often here in the north.

An online "local speed of sound" calculator gave me a LSS of 1078.012 at -50°C.

Even with the plane obviously protesting, I wouldnt think we were actually at the sound barrier... just closer than we might ought to be. The pilot did not mention anything about tailwind, but could it have been a jetstream that added some (serious) push? I am not familiar with the air currents over northern europe.

Just wanted to figure out how we ended up at those speeds, as on any other flight I've usually logged around 850-860kph steady for the same leg, both ways. Normal flight time is about 1 hour 20 minutes, this time we landed just short of an hour after takeoff.

So or so, it was quite the experience... although I think I would prefer not repeating it. http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/cwm13.gif

[mrdeux]

Groundspeed. Just lots of wind and the standard .78 mach....

[Aronn]

That doesent explain the heavy buffeting felt throughout most of the flight, though. The engine sound was also a lot more high-pitched than on any other of my 200+ 738 flights, indicating a higher RPM.

Also, without a jetstream - why wouldnt they normally use it if there was one - in the area, is ~240kph/130kts a normal wind/airflow strenght?

[mrdeux]

130 knots worth of wind is common. So is much more. The poor ride most likely goes with the wind. You were not doing anywhere near the local speed of sound.

[Aronn]

Guess that explains it then. Still weird with the engines running a lot harder/faster than normal, I think that added to the feeling of airframe stress (which again was completely different to that of any turbulence I've been in, some of which quite severe).

For the record I did not expect us to have gone much closer to the local speed of sound than "normal"/Mmo, it was just an onset of slight unease from what seemed to be airframe stress due to overspeed.

[The SSK]

I'm sorry, I've only been an aviation professional for 42+ years. Could you enlighten me as to where ENTO and EDDW are? So kind of you, thank you. My ignorance, I know.

[Aronn]

ENTO (http://en.wikipedia.org/wiki/Sandefjord_Airport,_Torp) = Torp(Sandefjord), Norway
EDDW (http://en.wikipedia.org/wiki/Bremen_Airport) = Bremen, Germany

[G-BPED]

I'm sorry, I've only been an aviation professional for 42+ years. Could you enlighten me as to where ENTO and EDDW are? So kind of you, thank you. My ignorance, I know.

ENTO is Sandefjord (Torp) Norway

EDDW is Bremen, Germany

Regards,

G-BPED

[The SSK]

Thank you

Hint - real aviation people don't use ICAO 4-letter designators, they are for posers and wannabes

[Kiltie]

This is a Spectator's Forum SSK.

[forget]

4 letters, 3 letters. Someone had to say it. :D I'm sick to death of seeing DUB for Dubai.

[Capetonian]

LOS for Los Angeles
TOR for Toronto

People who use codes should at least get them correct, easy enough to look them up.

[Kiltie]

So why won't you therefore criticise the OP for his lack of speed of sound or 737 knowledge? The guy is a spectator, not a professional!

[Aronn]

Well, there I learned something. "Flying people" usually use IATA codes to refer to airports? I was under the impression that IATA was for baggage tags and boarding cars while ICAO was "the" system used for airport identification, seeing as it is easier to identify where the airport is to start with and that there are no duplicates like there is in IATA(?). My aviation experience other than as pax is a lot of flight sim'ing (FS98 up, XPlane), as well as a few flying lessons, and I've always used ICAO for 'flightplanning' (Garmin G500/G1000).

[The SSK]

It was a perfectly fair question and was fairly answered at #2 and #4.

What irritates me is the regular use of ICAO designators by people who think that their use of them confers some sort of insider status – let’s face it, in most cases they are more like a secret code than a shorthand way to render an airport name (and yes, I know how they are constructed).

The IATA 3-letter designators, for the most part, are not difficult to decipher and are common, everyday usage within the airline business. I have a ‘vocabulary’ of probably 1500 of them and although that’s far more than I need, I do my job better armed with this knowledge. On the other hand, I have ‘almost’ never come across the use of the ICAO codes in the professional context, and I’ve worked just about everywhere except onboard and in the hangar. Where they were used – in the BA Prestwick ops room for example – it was just for official paperwork, the common currency was always the IATA codes.

So if you flew from TRF to BRE, why couldn’t you say so? I for one would know what you meant. (or has TRF just undermined my own argument?)

The SSK

[Kiltie]

I can understand irritation on an equal playing field of one of the professional forums, but to be sarcastic to a well-meaning spectator who doesn't share the same knowledge is unnecessary and patronising in my opinion.

[Aronn]

IATA it will be in the future then, I know both designators for the airports I'm involved with but thought ICAO was the proper one to be used. Sorry!

[Back at NH]

Not filed many flight plans then?

[forget]

but to be sarcastic to a well-meaning spectator who doesn't share the same knowledge is unnecessary and patronising

Aronn said - Even with the plane obviously protesting, I wouldn't think we were actually at the sound barrier... just closer than we might ought to be.

Hmm. He considers himself smart enough to criticise a professional flight crew, with enough detail for Ryanair to pin down names. He sees himself as smart enough to suggest, on a public forum, that a 737 was being operated beyond limits. Aronn is very lucky that no one has (yet) dropped into this forum who might take offence at his postings. When they do, which they surely will, the matter of ICAO codes will be as nothing - guaranteed.

[Back at NH]

We're not paranoid, it's just that everyone's out to get us:ugh:

Spotter asking a question about something he doesn't understand.....no accusation of wrongdoing..............educate and enlighten:ok:

[smallfry]

Well, those of us that do actually fly for a living use them all the time. We don't use the 3 letter codes at all.

When we talk about somewhere we say for example 'Heathrow', but for our job - flight plans, Notams, Weather, Sigmets Pireps etc, without the 4 Letter ICAO code we wouldn't get very far.

So in our world 4 letter code much better than 3 letter code.

As to the high speed 737?... Could only be a jetstream tail wind, which can be smooth or bumpy, but will give you the massive groundspeed.

[Aronn]

I did not actually mean to suggest that it was operated beyond its operational limits - rather AT these limits, it was more of a question of how one would reach such speeds (I am not familiar with high altitude air currents at all, and never exceeded 900kph on that "sector", if thats the right word, in the past), and why the plane was giving the impression of being just about to fall appart for 40 minutes or so.

It WAS also one out of two flights I've felt insecure in a plane, the other one nearly putting the aircraft upside down into terrain as the A/C flipped over (roughly 100 degrees from level) due to a strong windgust from the side on the turn to final. Approach to that airport has since been changed AFAIK.

Assuming, as always, that the flight crew on my flight were professionals, they have operated inside their limits and would have nothing to worry about should someone come across an anonymous complaining passenger on a public board. If they did not operate within their restrictions it would be better to give them a pointed finger now than waiting for something worse to happen as a result of going outside their limits again in the future. Also, I was not worried about the professionalism/airmanship of the pilots during the flight, I trusted they would keep the plane within its safety limits; it just felt unsafe to me as a passenger.

As a paying customer, I should be allowed to raise an eyebrow at a service that is perhaps not as good as one would expect. I would however ask people with more experience and knowledge about what might have happened first, rather than immediately sending a fax to Ryanair insinuating anything.

[eightyknots]

:rolleyes: It's at times like this that Rainboe is missed!

[Gulf Julliet Papa]

Hi Arron,

Just to give you an idea. Every single one of Ryanairs aircraft is fitted with an OFDM system. This system monitors, and at the end of the day sends data to Dublin. The data that it generally monitors are exceedances of any form (including flap speed, VMO/MMO (max speeds) etc.)

The 737-800 is limited to .82, Ryanair on average flies around between .78/.79 (dependant on weight). The -800 is a fairly unstable aeroplane when it comes to flight in turbulance. As you are suggesting that it was bumpy in the cruise, it would not be a great idea for the guys to increase the speed to fly at the limit of .82 as the -800 would overspeed very easily.

If the aircraft overspeeded multiple times within one flight I can garuntee that this would be followed by tea and biscuits in Dublin. No one wants this.

Looking through the feed I would suggest that the jetstream argument is the best one and would tie in with your constant turbulance.

Just some quick numbers using the basic nasa mach calculator (doesnt take into account anything like temp. etc.

Cruise = 38000ft (guess)
Speed = 520mph = 836kph
Mach = 0.787

So that would be still air conditions.

1078kph - 836kph = 242kph

This would be the tail wind you have to get 1078kph. 242kph is just above 130kts. You may not get 130kts every day but it does happen. Just be happy it was a tailwind rather than a headwind!

Hope that makes sense, and please excuse any mistakes in my maths!

[Aronn]

Thank you GJP. I agree, it sounds like it was just a bad hai...wind day. I am relatively familiar with ground speed/TAS/IAS/mach, I just failed to appreciate how windy it can get up there... I know there are these jetstreams up there somewhere, but I had it in mind that they were fairly stable(reliable) things and as they had never used them before I thought there wasnt one there.

"fairly unstable" would be a way to describe the flight :p

Never heard of the OFDM system before now, that is interesting.

Thank you!

[Callsign Kilo]

Gulf Juliet Papa speaks the truth here. The OFDM system is very real and flight exceedances are logged electronically. Flying around at 0.81/0.82 or 340kts within turbulent air/jetstream activity/pressure waves/convective activity is going to attract the wrong sort of attention. And we are not simply talking about the crew's level of airmanship being brought into question here! An overspeed also requires the aircraft to be inspected by an engineer as it is considered an exceedance that is detrimental to the aircraft's structural integrity. This would immediately highlight that a problem has occurred long before the OFDM gets the chance to download it's data at the end of the day.

I too would concur with the fact that you probably benefited from a north/south jetstream which contributed to a considerable groundspeed. The 'flex' that you witnessed on the NGs wings is fairly usual. As you enter and exit the jetstream you will certainly witness a bit of buffet as the wind velocity begins to increase or drop off.

[G SXTY]

It’s not that often we get the mighty Q400 up into a jetstream, but on the odd occasions when I have, wind speeds have been in excess of 110kts. Conditions can also be quite choppy, particularly at the jetstream boundary.

The experience you describe doesn’t sound anything special, and you can thank OFDM for the fact that very few pilots these days would want to push company limits, let alone airframe ones.

[The SSK]

I wish you could have found one on my last Q400 trip - two bloody hours (BRU-ZAG*).

Remind me again what the Q stands for?

*or if you must, EBBR - LDZA

[G SXTY]

You have my sympathy. ;)

Q - questionable?

[wiccan]

Thank you

Hint - real aviation people don't use ICAO 4-letter designators, they are for posers and wannabes
I have just retired after 48 years in aviation [ATC]...and all I ever used was ICAO codes....great, I wasn't doing a job, I was a wannabee [reasonable pay, though] :ok:

[FLCH]

After 30+ years of flying I can't decide whether I'm a poser or wannabe. Ah well, maybe I'm both.


It WAS also one out of two flights I've felt insecure in a plane, the other one nearly putting the aircraft upside down into terrain as the A/C flipped over (roughly 100 degrees from level) due to a strong windgust from the side on the turn to final. Approach to that airport has since been changed AFAIK.


I'd be curious to know how you estimated the angle of bank, and the subsequent procedural changes at the airport.

Not bashing you or questioning your judgment, just curious that's all.