'No speed'

[FlyingOfficerKite]

If you ask a pilot why it is normal to reduce to 250kts below FL100 s/he will no doubt respond that it is to assist ATC with the management of traffic and, coupled with windshield heat, to help reduce the effect of a bird strike.

On departure when given the option by air traffic of 'no speed' pilots smile, think of the possible saving in time, and happily select VNAV speed.

What about the possibility of a bird strike?

This never seems to be considered yet is potentially just as likely as on the descent.

Is this a case of doing what we are trained and taught, rather than what would appear to be common sense?

KR

FOK

[hetfield]

In our company SOP in that case was 280 kt, but only on one particular heavy type

[Meikleour]

Some large types like the B747 have clean speeds well in excess of 250kts. that is why they are usually happy to accelerate rather than have flaps extended up to 10,000ft.
Has been this way for well nigh 45 years. I have never seen any statistics to prove an increased risk level although I agree with you that there is an inconsistency here.

[tocamak]

My company sop is that if you are instructed to maintain a speed above 250k below Fl100 then you may do so but otherwise the limit applies i.e. "no speed" means there is no speed limit from atc but there is from the company

[ChristiaanJ]

FOK,
Dumb question from an ancient...

During a typical departure, how long would you expect to be "stooging" around below FL100 at more than 250 kts? More than about a minute or two?

Unlike an arrival, where you might well be required to "hang around" below FL100 in a hold for far more than a few minutes.

My thought being, that there would be an order of magnitude difference between time 'at risk' (or distance covered 'at risk') between a departure and an arrival.

CJ

[LeadSled]

FO Kite,
Certification takes care of bird strike, but in the GODs, I was always amused that the Imperial Standards Bird only flew to 8,000 ft, but the FAA Bald Eagle flew to 10,000 --- which hardly covers Condors over the Andes, where birdstrikes have been recorded at 28,000. I personally have had a bird strike --- at night --- at 17,000 over Bangkok ---- doing about 340kt at the time, hell of a bang, but no damage to the aircraft.

An aircraft AFM will detail any operational limits to ensure bird strike protection, but in more recent times, many aircraft (eg: B747) do not have any birdstrike limitation speeds.

Re. 250 kt/10,000' speed limits, some are statutory (eg:US) and ATC cannot give "dispensations", it is up to the PIC to determine that a minimum safe speed is greater than 250kt. From memory, FAR 91.117.

In some countries (eg: Australia) it is a bit more complicated, it is a statutory limit in D, E and G airspace, but up to ATC in C.

Tootle pip!!

[Denti]

Company limit of less than 300kts below FL100 and less than 250 below 5000ft/FL50 (applicable to all fleets, be it boeing or airbus). Those are hard limits and may not be busted in any case, be it departure or arrival. Within those limits we may help ATC with higher than 250kts, however if given "maintain highspeed" or "free speed" we have to reduce to 250, only when a specific speed is requested by ATC we may fly that if higher than 5000ft.

I'm quite happy with that, but it means i have to be a tad more conservative in my descent planning to cater for route shortening below FL100 which i cannot work around with a higher speed anymore. German airspace C has no speedlimit below FL100 which usually enabled us to fly faster than 250kts, until the company changed their inhouse limits that is.

[BOAC]

Originally Posted by ChristiaanJ

you might well be required to "hang around" below FL100 in a hold for far more than a few minutes.

- I'd be interested to see your 250kt hold.......................but not to be very close.................

[bbrunton]

Bird strike is only part of it.

Then main reason for 250 max below 10,000 ft is because that is what I call indian territory... That is where you will find the indians.. Cherokees, along with Cessnas and all manner of slow moving aircraft..

Also the cloud clearance and visibility requirements for VFR aircraft are based on a max airspeed of 250 KIAS.. Above 10,000 ft the VFR visibility and cloud distance requirements are greater due to the higher speed.

Bird strike requirements should be met by a combination of operating limitations and procedures such as Vmo and Mmo limits.


Bill

[Pugilistic Animus]

FAA speeds

(a) Unless otherwise authorized by the Administrator, no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots (288 m.p.h.).
(b) Unless otherwise authorized or required by ATC, no person may operate an aircraft at or below 2,500 feet above the surface within 4 nautical miles of the primary airport of a Class C or Class D airspace area at an indicated airspeed of more than 200 knots (230 mph.). This paragraph (b) does not apply to any operations within a Class B airspace area. Such operations shall comply with paragraph (a) of this section.
(c) No person may operate an aircraft in the airspace underlying a Class B airspace area designated for an airport or in a VFR corridor designated through such a Class B airspace area, at an indicated airspeed of more than 200 knots (230 mph).
(d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed.

[GlueBall]

Denti . . .

"less than 250 below 5000ft/FL50 (applicable to all fleets, be it boeing or airbus). Those are hard limits and may not be busted in any case, be it departure or arrival."

"Hard limits?" Have you ever flown B74s? . . . So if your flaps-up speed were 265, you'd rewrite the Boeing book, stay at "less than 250kts" and drag the flaps to 5000 feet?

[Denti]

It is a hard company limit. And no, we do not fly 747s, way too inefficient for our route network, 2 engine widebodies are much better for that.

[parabellum]

I seem to remember that there was a speed limit of 250kts below 10,00' if there had been a window HEAT failure?

[The Dominican]

250 kts bellow 10K

The origins of this regulation had nothing to do with bird strike protection because when the regulation was put in place in the early 50's who cared or was a bit concerned about bird strikes? think about it, your flying along in a tank like built DC6, DC3 or Connie and a bird strike was a non issue, but for an air traffic controller working without radar and in a congested airspace where most of the traffic wasn't going farter than 200kts. because after all, jets where a new thing in the 50's. Then the explosion of general aviation during the 60's and 70's brought the "Indian" phenomenon that somebody mentioned in an earlier post and again 250 bellow ten played a part in organizing traffic. All jets that I know of have a higher speed for bird strike protection than 250 bellow ten and all birds that pose a real danger because of their size (large migrating waterfowl for example) they all fly a lot higher than 10K. so the common sense argument of the original post is flawed. So if you are departing out of an airspace that has no speed restriction, please use your common sense and remember that the A/C taking off 45 seconds behing you is going to accelerate

[DFC]

(d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed.

I love the common inrepretation of that rule.

Very few people seem to notice that the above rule refers to safety and not in any way to economic or convenient operation.

Therefore, while one could argue that it may indeed be a pain in the ass and is not economic to fly a B747 at 250Kt with flap extended all the way to 10,000 it is 100% safe to do so.

If flying in Class E, F and G there is a hard limit of 250Kt below FL100 / 10,000ft because there is a posibility of encountering unknown VFR traffic and permitting the posibility of "see and avoid".

As was said previously, above FL100 the VMC minima are higher to account for the increrased speed and under ICAO, VFR flight is not normally permitted above FL195.

[ChristiaanJ]

Originally Posted by The Dominican

... flying along in a tank like built DC6, DC3 or Connie and a bird strike was a non issue...,

The DC3 may be pretty solidly built, but it's not birdstrike-proof.

BAC (British Aircraft Corp.) used a DC3 as a shuttle between Filton and Fairford. Very short run, so they didn't really get much higher than 2500 ft.
One day .... co-pilot bends down (to pick a pencil from the floor or suchlike).
The next moment there was an almighty bang just above his head.... a seagull had come straight through the windscreen and gone splat! against the bulkhead behind him.
He was showered with glass, blood and feathers, and the smell was atrocious, but he was not significantly injured.

CJ

[The Dominican]

I flew the "3" had several strikes with it too, so I am quite familiar with how it is built. You missed the point of my post since they didn't reduce the speed from 145 kts to 130 kts as a result of that particular incident did they? The point is that the regulation has nothing to do with bird strike protection but rather traffic management, what has to do with bird strikes is the several layers of glass and plastic which aircraft windshields are built today and all large transport aircraft's are certified to withstand a large bird impact at high speeds. the assumption of the original poster is incorrect

[Pugilistic Animus]

Never flew a 747 but I'd assume that the operators want to keep flaps down operations to a minimum out of respect for fatigue considerations....and i believe we can safely say that rule was made for her originally

[NG_Kaptain]

The FAA instituted the speed limit in the early 60's after a United DC8 collided with a TWA Connie over New York. The DC8 was flying real fast and overshot his fix ending up in La Guardia's airspace.

1960 New York air disaster - Wikipedia, the free encyclopedia

[Denti]

I know of a recent birdstrike on a 737 around 210 kias in 2000ft which managed to penetrate the captains window through all layers. However the captain was lucky and managed to not get injured by the shower of glass particles. So even below 250kts you might get suddenly feathered guests in the cockpit.