New York Plane Crash

[Papoo]

Los Angeles said:

My limited knowledge of this situation understands ice affects prop planes far more than jet aircraft because of the altitude prop planes fly, and because jet aircraft have heated wings. After a US crash a decade ago with a similar plane prop plane manufacturers were told by the civil air authority to fit de-icing "bags" alone the edge of wings. I don't know if the plane in this case was fitted with them. Myabe Eric knows.

You're right, icing may be more prevalent in the lower altitudes aircraft like the DHC-8 flies at. That said, this particular aircraft is a turbo-prop, which is essentially a jet engine which turns a propeller. They too, can pull off 'bleed' (warm) air to heat the wings. And yes indeed, it has de-icing boots. Not sure about the tailplane, however, but probably.

Eric & Bumblebee seem to be completely on the money, as usual. Brilliant explanations. If someone could find (I'm struggling) a decent explanation of tailplan deep/superstall to explain to everyone, that may be of use. Otherwise, thanks for some great informative specuation.

[Cara Van Man]

Our Bombardier aicraft has a variation of anti-icing.

Leading edge of wings is bleed air which comes down long telescopic tubes and several other leading edges are heated electrically.

[bumblebee]

Los Angeles said:

My limited knowledge of this situation understands ice affects prop planes far more than jet aircraft because of the altitude prop planes fly, and because jet aircraft have heated wings. After a US crash a decade ago with a similar plane prop plane manufacturers were told by the civil air authority to fit de-icing "bags" alone the edge of wings. I don't know if the plane in this case was fitted with them. Myabe Eric knows.

It's a bit of a generalisation but it tends to hold true: Piston engined light aircraft and turbo-prop commuter aircraft more often fly at low to medium levels where they spend more time in cloud where icing conditions occur. Higher performance swept wing jet aircraft fly high enough (ambient temperatures below -30C to -40C) such that the ice crystals encountered in cloud are small enough and 'dry' enough that they don't accrete. Swept wing jets also usually have wing aerofoil sections that are proportionately 'thinner' and 'pointier', whereas those of lower speed straight wing types usually have 'thicker' and more rounded wing aerofoil sections that are more prone to rime ice accretion.

There are two ways to anti-ice or de-ice the leading edges of wing/tailplane/rudder surfaces in flight. Jet aircraft tend to use ducted (hot) bleed air from the engines to melt the stuff off. Propellor aircraft tend to use inflatable de-icing 'boots' to mechanically break up the ice that accretes. Even though you might expect a turbo prop to use bleed air type system, they tend not to because they usually have a wing type without any moveable leading edge lift devices. This makes it difficult to design in a hollow bleed air duct. The Dash 8 uses 'boots' (if you look at a picture of one you'll see the black neoprene inflatable boots on all the leading edges).

The inflatable de-icing boot system has been in use for much longer than a decade!

[Mojocvh]

Los Angeles said:

bumblebee said:

The inflatable de-icing boot system has been in use for much longer than a decade!

Thanks for the comprehensive info, Bumblebee.

My reference to "decade" is in regard to the air authority's instruction to convert all prop planes to the system. I'm told many still have not installed the "boot," or bag, as I described it.

The question is, is the boot system manually or automatically activated?

Both.

[Mojocvh]

There is a more comprehensive thread on pprune if people are that interested/morbid.
I am sure that the quick recovery and downloading of the data and voice recorders by the NTSB will point to a very quick resolution of the cause and thus allowing quick follow-up for all Turbo Prop operators.

[Eric Mc]

The pre war Douglas DC-2 and DC-3 had rubber de-icing booths fitted so they've been around over 70 years.

Edited by Eric Mc on Monday 16th February 22:49

[bumblebee]

Los Angeles said:

My reference to "decade" is in regard to the air authority's instruction to convert all prop planes to the system. I'm told many still have not installed the "boot," or bag, as I described it.

FAA Fact Sheet on Flying in Icing conditions

Found this link this evening which may be of some interest. As a general point, most aircraft are either certified for 'flight into known icing conditions', or not. It is quite possible that the FAA had produced a directive that all aircraft used in commercial operations of that type should be equipped for flight into known icing. That would make sense. It can however take a number of years in some cases, for even significant air-worthiness modifications to be implemented. Can't find a specific reference for what you refer to unfortunately.

The interesting directive from my point of view is the one that refers to crew activating de-icing systems 'at the first sign' of airframe icing, which goes against the traditional thinking of the way de-icing boots are used, and certainly contradicts the training that many generations of pilots (including me) have had. - The traditional method made a particular point of not activating them until the ice accretion had accumulated sufficiently to ensure that the inflation of the boots would cause the ice to break away cleanly. It requires careful observation, because if done too soon the ice doesn't break away and begins to solidify and build up in the form of the inflated boot, which is what is known as 'ice bridging' (see the definition in the link above) and renders the system ineffective.