633Pneumatic Deice Boots Turboprop Aircraft

The following discussion is based on comments by Eugene G. Hill the FAA's chief scientific advisor for environmental icing. Eugene Hill had 36 years experience with Boeing, including extensive work on icing certification. He had a significant role in developing the FAA's current icing strategy. Manufacturers of most turboprops and some small jets are reviewing their recommended de-ice boot operating procedures and, in some cases, rewriting them. The activity stems from the FAA's July 1999...

4121General

De-icing anti-icing fluids are chemical products with an environmental impact. During fluid handling, avoid any unnecessary spillage, comply with local environmental and health laws and the manufacturer's safety data sheet. Mixing of products from different suppliers is generally not allowed and needs extra qualification testing. Slippery conditions due to the presence of fluid may exist on the ground or on equipment following the de-icing anti-icing procedure. Caution should be exercised due...

4123Storage

Tanks dedicated to storage of the de-icing anti-icing fluid are required. The tanks should be of a construction material compatible with the de-icing anti-icing fluid. They should be conspicuously labelled to avoid contamination. Tanks should be inspected annually for corrosion and or contamination. If corrosion or contamination is evident, tanks should be maintained to standard or replaced. To prevent corrosion at the liquid vapour interface and in the vapour space, a high liquid level in the...

644 Landing

Attempts to land on heavily contaminated runways involve considerable risk and should be avoided whenever possible. If the destination aerodrome is subject to such conditions, departure should be delayed until conditions improve or an alternate used. It follows that advice in the Flight Manual or Operations Manual concerning landing weights and techniques on very slippery or heavily contaminated runways is there to enable the Commander to make a decision at despatch and, when airborne, as to...

522 Icing Forecasts

(a) Is adequate icing information issued or included in aviation forecasts MetService Standards Manual Chapter 4 Section 2.1 states The Meteorological Service of Zealand provides aviation meteorological services in accordance with Civil Aviation Rules Part 174 Meteorological Service Organisations -Certification. These rules are issued as a requirement of the Civil Aviation Act 1990 It is the responsibility of organisations other than MetService (namely, the Designated Meteorological Authority,...

4131 Biological Degradation

The single glycols, like monoethylene, diethylene and propyleneglykol, are entirely biodegradable. Biodegradable means that aerobe bacteria changing glycol to water and carbon dioxide by the aid of oxygen achieve a conversion. For the different glycols there are minor differences with regard to the rapidity of biodegradation and the oxygen used. Also the temperature is an important parameter. Biodegradation results faster at higher temperatures and slower at lower temperatures. The best way to...

13 Airframe Icing and Cloud Type 131 Cumulus Type

Cumulus-type clouds consist predominantly of liquid water droplets at temperatures down to about -20 C. Below this temperature either liquid drops or ice crystals may predominate. Newly formed cloud segments will tend to contain more liquid drops than mature parts. The risk of airframe icing is severe in cumuliform clouds in the range O C to -20 C. Airframe ice is unlikely below -40 C. The vertical motion in a convective cloud varies its composition and corresponding ice risk throughout a wide...

722Stall Unusual Attitude Recovery Training

Instrument flying training accounts for unusual attitude recovery however carrying this on to 'upset' training, involving the variables of an iced up aeroplane, is hardly practical. Moderate to severe ice accrual creates entirely new, unpredictable aerodynamic flow over the wings and tail. Airfoil shape, aerodynamic flow, the relationship of forces and design logic are all subject to random changes unique to the specific ice encounter. The pilots of the Comair EMB-120 that crashed after a roll...

642Operational Factors

At major aerodromes, when clearing has not been accomplished, the runway surface condition is reported as follows The presence of water on a runway will be reported to the pilot using the standard descriptors. For performance purposes, runways reported as DRY, DAMP or WET should be considered as NOT CONTAMINATED. Depths greater than 3 mm of water, slush or wet snow, or 10 mm of dry snow, are likely to have a significant effect on the performance of aeroplanes. The main effects are (a)...

727 InFlight Training Aircraft

Per-flight briefing similar to that for the simulator program. Operation of de-ice systems. Stall recovery at the buffet, aggressive use of attitude and power. Unusual attitude recovery, ADI EADI presentation and interpretation, recovery technique. A key feature of unusual attitude recoveries is the ability to interpret the ADI EADI. Familiarisation with these presentations does not necessarily involve elaborate simulation rather it may be accomplished using simple models made from cardboard or...

177Ice Intensity Pilot Action

Rate of accumulation of ice is slightly greater than the rate of loss due to sublimation. (b) Light The rate of accumulation may create a problem for flight in this environment for one hour. Unless encountered for one hour or more, de-icing anti-icing equipment and or heading or altitude change not required. (c) Moderate The rate of accumulation is such that even short encounters become potentially hazardous. De-icing anti-icing required to remove prevent...

165 Tailplane Stall Symptoms

Warning Once a tailplane stall is encountered, the stall condition tends to worsen with increased airspeed and possibly may worsen with increased power settings at the same flap setting. Airspeed, at any flap setting, in excess of the aeroplane manufacturer's recommendations for the flight and environmental conditions, accompanied by uncleared ice contaminating the tailplane, may result in a tailplane stall and uncommanded pitch down from which recovery may not be possible. Tailplane stall...

242Recognition

Should no preventative action have been taken, or was taken too late, or was insufficient, the onset of induction icing may be recognised in the following ways (a) with a fixed pitch propeller, a slight drop in RPM is the first sign which may indicate the onset of icing in the induction system. If not rectified there will be a loss of airspeed and possibly height. The loss of RPM may be gradual with no associated rough running. The usual reaction is to open the throttle slightly to restore the...

11Icing Hazards

It destroys the smooth flow of air, increasing drag, degrading control authority and decreasing the ability of an airfoil to lift. The actual weight of the ice on the aeroplane is secondary to the airflow disruption it causes. As power is added to compensate for the additional drag and the nose is lifted to maintain altitude, the angle of attack increases, allowing the underside of the wings and fuselage to accumulate additional ice. Ice accumulates on every...

24 Prevention Recognition and Remedial Practices 241 Prevention

Whilst the following provides a general guide to assist pilots to avoid induction system icing, the Pilot's Operating Handbook or Flight Manual must be consulted for specific procedures applicable to a particular airframe and engine combination. The procedures are likely to vary between different models of the same aircraft type (a) heating the intake air in an exhaust heat exchanger before it reaches the carburettor prevents carburettor icing, (Design Requirements typically demand a...

4142Stationary Equipment

Stationary de-icing anti-icing facilities, currently available at a limited number of overseas airports, consist of a gantry with spraying nozzles moving over the aircraft, similar in concept to a carwash. The advantage of such a system is a fast and thorough treatment of the surface of the aircraft. As computers can operate these systems, working errors are practically excluded and consistent quality can be ensured. The disadvantage, however, is the operational bottleneck. If only one system...

521 Air Mass

(a) In New Zealand, which air masses streams are conducive to icing The simple answer is conveyor belts. These may be associated with surface cold, warm, occluded or even stationary fronts. Sometimes, however, there is no related surface front though there may be an upper front. It should also be mentioned that deep convection, which can occur in air masses which themselves are not conducive to icing, is also a major icing risk. (b) Which air masses streams become hazardous after modification...

54 New Zealand Statistics

During the five years from January 1995, New Zealand CAA recorded 487 aircraft accidents and 1940 incidents, a total of 2427 occurrences. 13 of these were attributable to in-flight icing - a rate of .53 . This analysis has been treated with caution due to the absence of a dedicated icing database and reluctance of some pilots to report icing occurrences. Nevertheless the rate is significantly lower than the FAA, so low in fact that Authority research led to the conclusion that a warmer...

255Immediately before Take off

Induction icing can occur when taxiing at low power or when the engine is idling. If the weather conditions appear to be conducive to the formation of induction icing then the HOT position should be selected before take-off for sufficiently long enough to remove any accumulation which may have occurred. If the aircraft is kept at the holding point in conditions of high humidity it may be necessary to run up the engine to the take-off power setting more than once to dear any ice which may have...

51Statistical Comparison

In 1999 CAA commissioned a study into the aircraft icing hazard in New Zealand. The resultant paper included a comparison of the US accident rate due to icing with the New Zealand experience. The local rate proved to be significantly lower. In fact the New Zealand rate was so low, it was difficult to reconcile it with statements by SAAB and ATR pilots. The commuter crews were adamant that icing in New Zealand was as severe, if not worse, than the encounters they experienced in Europe and the...

724An Alternative Program

Alternatively, training should focus on classroom education supplemented with practical training in either a simulator or an aircraft, the goal of the training being enhanced pilots knowledge and awareness. This awareness should include icing considerations, recognition of icing situations, escape strategy, recognition of potential upset situations and escape from these situations. This training needs to be formally incorporated during every phase of an operator's pilot training program...

21Introduction

Piston engine induction system icing, commonly, but not completely accurately, referred to as 'carburettor icing' may occur even on warm days, particularly if they are humid, IT CAN BE SO SEVERE THAT, UNLESS CORRECT ACTION IS TAKEN, THE ENGINE MAY STOP. Induction system icing is more likely at low power setting such as those used during descent, holding, on the approach to a landing or during auto-rotation on a helicopter. Statistics continue to show an average of 10 occurrences, including 7...

162 Ice Secretion

The shape of the ice that forms and the amount of ice that accumulates primarily influence aerodynamic performance degradation while the amount of liquid water in the cloud and the duration of the exposure to icing primarily determine the quantity of ice collected. Cloud droplet size is generally a secondary consideration. Temperature can determine the amount of accretion if it is close to freezing, some of the intercepted water droplets blow off before they can freeze. Ice accretion shape is a...

153 Wing Tip Stalling

Normally, washout helps to ensure that the symmetric stall starts inboard, and spreads progressively, so that roll control is not lost. Greater ice accretion has probably occurred at the tip, leaving it more impaired aerodynamically than the inboard wing section. Stall, instead of starting inboard, may start at the tip. Because the tip section may have a sharper nose radius and probably has a shorter chord, it is a more efficient ice collector. As a result, ice accretion at the wing tip may be...

884 Program for Relief of Ice Drag Fuel Penalty in Critical Fuel Scenario

This program for ice drag fuel relief applies to the mid-Pacific routes between the U.S. mainland and Hawaii. This area is relatively free of icing. Data from the U.S. Marine Climatic Atlas indicates percentage frequency of icing in winter ranges from a high of 30 in Seattle, to 12 in Oakland, to 0 in Hawaii. The program has certain constraints. There is no relief granted in this program for the anti-ice penalty (use of) which is provided in the manufacturer's data (e.g., 6 fuel penalty for use...

22Induction System Icing

There are three main types of induction system icing The most common type of induction system icing is carburettor icing which is caused by the sudden temperature drop due to fuel vaporisation and reduction in pressure at the carburettor venturi. The temperature reduction may be as much as 20 - 30 C and results in moisture in the induction air forming ice. The ice gradually builds up, constricting the venturi and, by upsetting the fuel air ratio, causes a progressive decrease in engine power....