Validation Tests

Results of Validation of EIDS Created & Developed by PWT-Impulse Ltd.

1. Flight test evaluation (Russia/USSR 1967-2007)


  • Standard Aviation Industry
  • Certification Norm for civil aircraft, NGLS (similar to FAR 23 and 25 – FAA approved bilateral agreement)
  • Certification Norm military aircraft OTTVVS
Removal Ice EfficiencyProtection ZoneAltitude (m)Temp icing (C°)ce rate mm/minIce thickness mm
EIDS 1st GenerationFlight Test
IL-86, IL-76, AN-124, IL-96, IL-96T, AN-140 etc.
100% ice removal after 1 cycle.
Wing, slat and stabilizer0-10.0000 to -500,25-4,52/2,5 to 40
EIDS 2nd GenerationFlight Tests
IL-86, IL-76, AN-124, IL-96, IL-96T, AN-140 etc.
100% ice removal after 1 cycle.
Wing, slat, stabilizer, air-intake and fin0-10.0000 to -430,2-4,26 to 40
Ice Wind Tunnel
100% ice removal after 1-2 cycles.
Slat and stabilizer IL-86, Stabilizer AN-1240 to -206 to 30
Freezing Chamber
Ice removal 100% After 2-3 Cycles.
Slat and stabilizer IL-76 and IL-86-5 to -356 to 12
EIDS 3rd Generation100% ice removal after 1-2 impulses (3rd generation 50-100% more efficient).
Increased efficiency with composite materials
Wing and stabilizer IL-114, Accord-201, UAV and A-400-2 to -302 to 12
Root section for western Business Jet (2,5 mm skin due to engine mount reinforcement)
Stabiliser of Smaller General Aviation Aircraft
Slat Test for Western Business Jet (preliminary design)


  • EIDS has no adverse influence on the electrical, flight navigation and radio equipment fitted in all the above indicated aircraft.
  • The system does not need any pilot intervention when switched on during icing conditions.
  • The system does not influence in any way handling qualities of the airplane in icing conditions.
  • No noise during flight.
Military Register, Russian Certification Department). Statement from test pilot after 4.42 hours in natural ice conditions with IL-38.

Efficiency increases with increasing ice intensity. Normally, just one cycle removes all the ice. At low ice intensity (layer 1,5-2,0 mm) one cycle may not be sufficient, but the ice layer of 1,5-2,0 mm does not influence the flying of the aeroplane.’

The advantages of EIDS are as follows:
  • It provides ice protection within extensive temperature ranges, compared to thermal systems.
  • Possible to control the switching on and off of the EIDS.
  • Efficiency increases with increasing icing rates.
  • No appearance of “barrier ice”.
Russian Aviation Authority

After extensive testing and years of operation the certification process was simplified for EIDS compared to traditional systems /State Standard No 21508-76 ‘Protection aircraft from icing’.

2. Validation & Evaluation – Performed in Western Countries

England (license agreement 1974-76), France (license agreement 1971-1983), US (license agreement 1980 via France) and Sweden (mutual project 2003).

Includes approvals by:
  • France Aviation Industry
  • British Civil Airworthiness Requirement
  • FAR
  • Ice Removal (efficiency)
  • France 1974-78
  • England 1974-76
  • USA 1983-86
  • In Flight
Slat (section) A-300
Intake Alpha Jet
  • 1. System fulfilled its de-icing function in all condition encountered.
  • 2. Efficient de-icing. EIDS avoid runback and refreezing.
  • 3. Quality of de-icing slightly less that quality of anti-icing.
  • Work reasonable well on wing (section) of BAC 1-11
Wing section DHC-6 (21 flights in icing)
Wing section DHC-6 (21 flights in icing)
  • Wing struts empennage Cessna-206 (15 flights in icing

~ Stabilizer ‘Caravelle’
~ Stabilizer ‘Mercure’
~ Air intake ‘Fouga 90’
~ Wing slat ‘End piece’ Airbus A-200

1. All wind tunnel test confirmed the feasibility &efficiency of the EIDS
2. Efficient de-icing. This system can advantageously be used on any existing aircraft for ice protection.


Thirty minutes encounters of icing conditions can be simulated over a range of air temperature at an air speed representative of the aircraft.

The effect of de-icing was clearly beneficial and the ice was controlled to a safe level  (section wing B.A.C1-11)

Rolls-Royce IWT

~ EIDS breaks up the ice into small enough pieces, posing no danger to the plane fuselage.

~ EIDS definitely saves weight and energy /intake engine RB-211/.


1. EIDS can de-ice general aviation wings over wide ranges of atmosphere & icing conditions.

~ Wing ‘Beach Bonanza’
~ Wing ‘Cessna 206’
~ Wing ‘Lear Jet’

2. Wings de-iced successfully  (NASA, Cessna & others).

3. Engine Inlet:

~ Efficiency de-icier
~ Ice fragments have to be small enough to be safelly ingested by turbo fan engine.

4. Tested:

~ Falcon Fanjet Inlet
~ Fokker 50 inlet
~ Inlet A310

‘System works optimally with 1/10” or greater ice build up. Effectiveness very good’. Joint ROHR /GE/ Boeing Program.


1. No EMI
2. No noise observed in flight
3. System safety confirmed by bird impact and lightning tests on various military and civil A/C

Companies & organization Air equipment, Airbus, French Government laboratory Lucas Aerospace, British Aerospace, Rolls Royce FAA (certified IL-96 including the EIDS system), NASA, Boeing, Cessna, ROHR, GE & others

3. French development test run (1976-1978)

11-12/4-76 Icing wind tunnel of MODANE. Part tested: a vertical fin of CARAVELLE

10/11/76 to 19/1-77 Endurance and fatigue test on an aircraft structure in a Government test laboratory.

Part tested: a section from the horizontal stabilizer of MERCURE.

2/1-77 to 15/3-77 Endurance test on an aircraft structure at AIR-EQUIPMENT.

Part tested: a section from the horizontal stabilizer of AIRBUS.

17/6-76 Electromagnetic radio noise test at AEROSPATIALE laboratories. Test rig: flat metal sheet.

23/6-77 to 31/6-77 Electromagnetic radio noise test at Government Test Flight Centre. Test rig: flat metal sheet.

31/1-77 to 78 Endurance test on SDI system components Test rig: flat metal sheet.

31/1-77 to 29/4-77 Endurance test on electrical wiring Test rig: flat metal sheet

25/8/77 Bird strike air gun in a Government Laboratory Part tested: airframe section

3/9-77 to 23/9-77 Test in a Government icing wind tunnel. Part tested: a section from the horizontal stabilizer of MERCURE.

17/11-77 Test in a Government icing wind tunnel.

Part tested: the left side air intake of ALPHA JET, feeding a LARZAC engine in operation.

1977-78 Flying test on AIRBUS.

Part tested: a section of the Nr. 1, right side, moving slat.

Flying test on ALPHA JET. Part tested: engine air intake duct.

Inductor Test

173 inductors tested for 458.000 hours showing no fatigue

4. Fatigue Test

With ice: < 1,5kg/mm2 With no ice: < 2 kg/mm2 /PWT & Ilyushin/[/av_cell][av_cell col_style='']Level never exceeded 4HB. Test did not cause damage to structure modified to accommodate the EIDS.[/av_cell][av_cell col_style=''][/av_cell][av_cell col_style=''][/av_cell][/av_row] [av_row row_style=''][av_cell col_style=''][/av_cell][av_cell col_style='']/Government test laboratory France and Air equipment./[/av_cell][av_cell col_style=''][/av_cell][av_cell col_style=''][/av_cell][/av_row] [/av_table] [/av_one_full] [av_one_full first] [av_heading tag='h3' padding='10' heading='5. Reliability Data‘ color=” style=’blockquote modern-quote’ custom_font=” size=” subheading_active=’subheading_below’ subheading_size=’15’ custom_class=”]
Ilyushin stated following in 2002.

Operating Reliability and Safety of EIDS on IL-86 from 1981 to 2001.

  • For all period operating EIDS had not lead to any problem relating to safety of aircraft.
  • EIDS had not lead to any problem relating to normal operation of aircraft (never when EIDS has been in use).
  • EIDS has not lead to any problem relating to delay in departure times.
  • Any failure of EIDS unit can be removed in permissible time of EIDS running, i.e. “delayed failure” what does not need an immediate intervention by a technical stuff).
  • At present determined service life for IL-86 is 30 years and 40 years for IL-38 (IL-38M), and 20 years or 20.000 flying hours for IL-96.
  • At present IL-86 has accumulated 1 million 300 thousands flight hours.
  • EIDS on IL-86 has considerable lower failure rate compared to typical hot air systems.

S7 (former Sibir) Ilyushin operator stated following in 2007.
– Fleet of planes with PWT EIDS (~12 IL-86 and ~250,000 flight hours)

– Safety

  • No event whatsoever involving ice
  • IL-86 operation speeds do not change due to efficient ice removal

– Dispatchability

  • No delay caused by problems with de-icing system
  • Redundancies in the system allow dispatch even with failures in some inductors (planes with bleed air has much higher failure rate with failing valves etc.)

– Maintenance Cost

  • Simple and low cost inspection/maintenance
  • Wiring failures (if any) will appear only after 15,000 flight hours due to fatigue caused by slat movement – almost no failure in the horizontal stabilizer – 3 failures in total)

6. CAA (United Kingdom)

Safety Regulation Group of the United Kingdom’s Civil Aviation Authority (CAA) and Loughborough University stated that EIDS developed by PWT was one of two systems selected for ‘Tailplane Icing project’.

7. Operation EIDS (in the natural conditions of ice formation)

Russian Aviation Register performed extensive research on 13 IL-86 aircraft. There were 803 cases crossing icing zones in 9.829 flights. The EIDS system was automatic controlled in 92,5% of the time and manual controlled in 7,5% of the time. Total time in icing conditions was 586 hours.

  • Temperature
  • -5 to 0
  • -10 to -5
  • -15 to -10
  • -20 to -15
  • -25 to -20
  • -30 to -25
  • -35 to 30
  • -40 to -35
  • -40 to -46
  • Total Flights:
  • Flights
  • 267
  • 156
  • 172
  • 87
  • 48
  • 41
  • 15
  • 13
  • 4
  • 803

The EIDS system did neither lead to any problem relating air safety nor any problem relating to normal flight operation.
/Ministry of Citizen Aviation, Report No. 01840006152, 11/06-1985/

8. FAA Certification, Statement & Conclusion

A. Certification:

FAA has approved the Russian certification methods and IL-96T including the EIDS system.

Russian certification is based on a combined flight tests and ground laboratory test of leading edge sections in freezing chambers. The Certification authority experience with EIDS has shown the EIDS efficiency neither depends on the temperature, the liquid water content, or intensity of icing.

This results that any demonstrated de-icing will guarantee de-icing in all other icing conditions (essentially simplifies certification of a system).

The system always de-ices better in flights compared to ground test.

‘The FAA and Russian government signed a Bilateral Aviation Safety Agreement (BASA) with Implementation Procedures for Airworthiness (IPA) in December 1998.
This agreement is based on a high degree of mutual confidence in Russia’s technical competence and regulatory capabilities to perform the obligations with the scope of the BASA IPA. Under this agreement, the FAA has issued type certificates for two Russian aircraft: the Ilyushin-103 and the Ilyushin-96T.

B. Advantages & Limitations

Advantages of the EIDI system are:

a. Low power required. Compared to hot air or electro-thermo anti systems, EIDI energy is about 1% as great. It is claimed that power requirements for an EIDI system are about the same as for the landing lights for the same aircraft.

b. Reliable de-icing. Ice of all types is expelled, with only light residual ice after the impulses.

c. Non-destructive in the airstream, hence no aerodynamic penalty.

d. Weighty comparable to other systems.

e. Low maintenance. Since there are no moving parts, the system should, in principle, be maintenance free.

f. No run-back re-freezing occurs.

Limitations of the EIDI system are:

a. It is new and has limited use at this writing (1986)

b. It is not an anti-icing system, so some ice will be present over most of the aircraft leading edges during icing flight. This drawback is inherent in any de-.icing method.

c. Electromagnetic interference (EMI). The discharge to create transient electromagnetic fields might be expected to cause undesirable signals in communication, control, or navigation equipment. However, both laboratory and flight tests have failed to detect any interference.

The reason suggested for this are:

a. The frequency of the pulse is below 3 kHz, which is below that of current aircraft avionics systems, and
b. The pulse is a pure wave (or half wave) without the “overtones” of a spark.
In flight tests, added equipment has been carried specifically to detect EMI; these included LORAN-C, digital readout systems, and a radar pod mounted on the wing.