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Fast And Low In Jets

negatory

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Some countries (and foreign controllers) allow jets to fly fast at lower altitudes. (Above 250 KTS below FL 100)
Some pilots claim that this have many disadvantages and risks. Can you share some thoughts of the risks for passenger jets? I am thinking of speeds above 250 kts below FL100 and stuff like bird strikes, CFIT, VFR traffic separation, GPWS/TCAS warnings, fuel consumption and so on…
(I was trying to find information or recommendation from Flight Safety Foundation about high speed at low altitudes but could not find anything.)
 

labbats

Zulu who?
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I always thought it had to do with the rule of mandatory transponder use above 10000, and keeping us away from slower moving pistons. The controller's main role is always aircraft seperation. But noise abatement is probably just as likely.
 

STL717

CL-215 Lake James, NC
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If It Hurts So Much, Why Would You Do It?

On January 9, 1998, at 19:25 local time, a Boeing 727-200 departed Houston, Texas. While climbing through 6000 ft. the crew heard a loud bang followed by intense vibration in the airframe. The noise level in the flight deck became so high that communication among the flight crew was almost impossible. The reasons for the noise and vibration are as follows: The No. 1 engine had lost a number of fan blades, resulting in violent vibrations that caused the cowling doors to become unlatched. The No. 2 engine also lost fan blades, and the No. 3 engine had a damaged pylon. The radome had been destroyed and departed the aircraft along with the radar antenna. The pressure bulkhead was penetrated, and the leading edges of both wings were damaged. The Kruger flap on the right wing was punctured, as was the wing adjacent to the flap. The right inboard slat and the wing area adjacent to the slat suffered the same fate. The first officer’s pitot tube was torn from the aircraft, rendering his airspeed indicator unusable. Overall, there was about $5,000,000 damage to the aircraft.

The cause of the incident was the aircraft’s collision with a flock of migrating snow geese, a situation that occurs far too often in North America these days, likely because of burgeoning populations of some species of waterfowl. However, the extent of the damage to the aircraft was probably greater than to be expected because of the high-speed departure trial that the aircraft was involved in. The Federal Aviation Administration (FAA) does not allow aircraft to fly above 250 kt. below 10,000 ft. mean sea level (MSL) in the United States, but trials were being conducted at the George Bush Intercontinental Airport (IAH) allowing aircraft to exceed 250 kt. on departure to test for gains in efficiency. At the time of impact, the B727 was flying at 280 kt. and still accelerating. The captain concluded that the high-speed departure program was "not a good idea." The outcome of the incident may not have been so favourable except for the fact that he had two second officers on board, providing a four-person flight crew to work through the check lists.

A discussion on the nuances of airworthiness requirements and speed restrictions below 10,000 ft. would fill several Aviation Safety Letter newsletters, but suffice it to say that the impact force resulting from a bird strike increases with the square of speed, and every 10 kt. of increased speed results in considerably greater damage. Whether or not efficiencies are gained by high-speed departures is debatable, and, furthermore, aircraft components such as engines, windshields, and leading edge devices are not designed to withstand high-speed impacts with large birds. In Canada, the Canadian Aviation Regulations (CARs) allow aircraft to exceed 250 kt. below 10,000 ft. above sea level (ASL) on departure or in accordance with a special flight operations certificate. Since most bird activity occurs below 10,000 ft. and high-speed departures likely keep you in that airspace longer, why would you want to exceed 250 kt. when the only advantage might be a few minutes of time saved? Is it worth the risk to yourself, your passengers, and your aircraft?

For additional information, please contact: Bruce MacKinnon, Wildlife Control Specialist, Transport Canada, Aerodrome Safety Branch, Phone: (613) 990-0515; Fax: (613) 990-0508; E-mail: mackinb@tc.gc.ca
 

radarlove

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Frozen Chickens

Mythbusters did a great job (urban legend about needing to thaw the chicken/turkey before testing birdstrike ability) showing the amazing amount of damage a bird, frozen or not, does to an airplane, even in sub-200 knot travel.

I will never, even off-shore, go more than 250 knots below 10,000 after this show.
 

Thedude

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radarlove said:
Mythbusters did a great job (urban legend about needing to thaw the chicken/turkey before testing birdstrike ability) showing the amazing amount of damage a bird, frozen or not, does to an airplane, even in sub-200 knot travel.

I will never, even off-shore, go more than 250 knots below 10,000 after this show.

The test they did was flawed and they addmitted it on a later show. They were firing a frozen chicken and a PA-28 window.
If you have ever seen the FAA video of the real testing you would have known this was bull from the get go. Large a/c windows are multi-layered and are heated which makes the a little more flexable than you standard windscreen.

I used to love coming in from off shore into JFK and being able to keep the speed up to at least 300kts.
 

Cardinal

Of The Kremlin
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Like when some kid drives into a bridge abutment, the cops always say "speed was a factor." Well of course it was a factor!! The whole point of buying these aircraft was to get from A to B faster. In order to keep risks on the order of sitting in your living room couch, well, you have to stay on your couch. As soon as you start moving there's stuff you might run into.

Regarding STL717s Transport Canada example: Take a peek at any of the birdstrike pictures on the net and you see similar damage after an encounter with a flock of geese, ie radomes destroyed, leading edge damage, and blade loss. The KC135 lost in Alaska was only doing 150kts when it was brought down.
 

radarlove

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Thedude said:
The test they did was flawed and they addmitted it on a later show. They were firing a frozen chicken and a PA-28 window.
If you have ever seen the FAA video of the real testing you would have known this was bull from the get go. Large a/c windows are multi-layered and are heated which makes the a little more flexable than you standard windscreen.


Yeah, and if you'd ever seen the pictures from the Lear that took a goose through the windshield and decapitated one of the pilots, you'd realize what a stupid statement you made in this next sentence:

I used to love coming in from off shore into JFK and being able to keep the speed up to at least 300kts.
 

Jack Mahogoff

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In the E-145 the red line is a sliding scale from 8,000' to 10,000' from 250 KIAS to 320 KIAS. So if you do above 250, at or below 8,000', you get the same thing you'll get when you get home from a 4 day.... yelled at by a woman. Ding Ding Ding, High Speed!
 

Wasted

u can do it too w kandoo
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Jack Mahogoff said:
In the E-145 the red line is a sliding scale from 8,000' to 10,000' from 250 KIAS to 320 KIAS. So if you do above 250, at or below 8,000', you get the same thing you'll get when you get home from a 4 day.... yelled at by a woman. Ding Ding Ding, High Speed!

Not all of them are that bad.
 

G4G5

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Going fast on the arrivals in Europe is quite common. Most arrivals will have a grey square on the arrival with the letters SLP next to it. This is the Speed Limit Point where you will be required to be reduced to a certian speed typically 250k or 210k, prior to that speed is at your discression

When I went through Gulfstream 4 maint initial they showed a video of a frozen turkey (I want to say approx 20lbs) being shot into the inlet of a Rolls Royce Tay (F100 motor). The damage was contained and the motor kept on trucking. They also showed a fire hose being shot directly into the inlet of the motor, H2o full force. Motorkept on trucking.

Try slowing down early into ORD or departing ATL to slow and see what happens.
 

Chronic Jetlag

I'm great at sleep'n in
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SexyTm
Some planes at MGTOW are unable to fly at 250 kts upon reaching acceleration alt. after clean up. Clean speed for maneuvering can be as high as 270-280 kts. Obviously you're not going to fly with the slats extended up to 10K just to maintain 250kts. Some wide body heavies like the 747-4, MD11 would climb out at well over 250kts. All you gotta do is request "normal speed" I forgot which part of the FARs but you CAN exceed 250 below 10K if operationally required. Controllers at big airports are well aware of this unique situation.
 

Fly-n-hi

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91.117 AIRCRAFT SPEED



(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 m.p.h.). This paragraph (b) does not apply to any operations within a Class B airspace area. Such operations will comply with paragraph (a) of this section.

(c) No person may operate an aircraft in the airspace underlying a Class B airspace area, or in a VFR corridor designated through such a Class B airspace area at an indicated airspeed of more than 200 knots (230 m.p.h).

(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.
 

mdanno808

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I am currently flying a contract in Europe, and would like to add a couple of comments. Many aircraft have limitations on speeds below 10000 ft due to bird strikes (the B 757 is 313 kt below 8000), however, those numbers are often not published in American manuals (due to the fact that it is illegal to fly speeds greater than 250 below 10). In Europe, it is common to fly to an airport without a speed restriction. Also, in the UK, most airports have a speed restriction of 250 within the TMA and at or below 10000ft, however, they will often release you from the restriction. I am not sure where the 250 below 10 rule came from in the US, but it is definitely not a world wide thing. One things for sure, unless you're paid by the hour (which I am not) the faster you fly the more your hourly wage ends up being.
 

Beertini

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Apples and Oranges

Cardinal said:
....The KC135 lost in Alaska was only doing 150kts when it was brought down.

The aircraft that crashed in Alaska years ago was actually an AWACS. It ingested (21 I think) Canadian geese into the #1 and #2 engines while on takeoff roll and subsequently crashed after continuing the takeoff. Sorry, but that accident isn't a good example for airborne bird strike discussions.

Beertini
 
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