An overview of the FAA's icing program is presented. The program involves certification of various types of aircraft for flight in known icing conditions, the study of icing conditions, and the preparation of certification standards. Test and technology transfer programs are also included

Czekalski, L.

English

NASA Technical Reports Server

‘OVERVIEW OF FAA’s AIRCRAFT ICING PROGRAAP 
Loni Czekalski 
The Aircraft Icing Accident Summary (Figure 1) 
shows statistics which were taken from National 
Transportation Safety Board (NTSB) records and 
the FAA’s Accident Incident Data (AID) system. 
If you look at the number of accidents over about 
the last five and one-half years, from January 1978 
to June 1983, you will find that there were 280 
accidents which resulted in 364 fatalities and 171 
injuries. The accident injury-to-fatality ratio is 
about 2 to 1. It is said that if you are involved in 
an icing accident, you probably will not walk away 
from it. It is a very serious accident in which to 
be involved. 
1978 THROUGH JUNE 1983 : 
TRANSPOPT (121) 99 5 6 10 
COMUTER (135) 19 23 30 11 
GENERAL 
ROTOR (1 f (5) (8) 
63 OTHER/UNKNOWN 
F A S A L I T T E S m - l N C r D E N T S  
63 (1) I AVIATION (911 184 95 i a i  
2 - - 48 - 62 - 
TOTALS: 364 171 280 a6 
AVERAGE PER 
YEAR: 66 31 51 
Figure 1 .  Aircraft Icing Accident Summary 
In a breakdown of the statistics (Figure 2), 
we find that 35 accidents occurred in super-cooled 
clouds; 31 in freezing rain and drizzle; and 39 in 
snow. When the FAA regulates that you must 
be certified for flight in known icing conditions, 
this certification actually certifies only for flight 
in super-cooled clouds. This information tells us 
that we have almost as many accidents in freezing 
3Y WEATHER: 
CLIMB/CRUISE/DESCENT/APPROACH PHASES ONLY 
WEATHER BRIEFING : ADEQUATE 116 
INADEQUATE 55 
NONE 4 
UNREPORTED 7 
S ‘J PER- COO LED CLOUD 35 
FREEZING RAIN/DRIZZLE 31 
SNOW 39 
OTHER/UNKNOWN 77 
Figure 2 .  Weather Statistics o f  Aircraft Icing 
Accident Summary 
rain and drizzle as in super-cooled clouds, with 
even a larger amount of accidents in snow. 
Although we do not set a criteria, our reg- 
ulations tell you that you must be able to fly in 
both falling and blowing snow. Figure 3 outlines 
the current regulations relative to the certification 
of both small and large aircraft for ice protection. 
Both FAR 23 and 25 reference the FAR 25 Ap- 
pendix C; but only FAR 25, which is for the large 
transport category aircraft, references the falling 
and blowing snow. 
Zn talking to the aviation community, we have 
learned some very interesting things (Figure 4). 
As your initial operating costs have increased, the 
buying of aircraft has become more expensive. The 
operating costs to maintain that fleet, because of 
the increase in labor and fuel costs, have created 
more and more concern about fleet productivity. 
SMALL AIRCRAFT: 
23,1093 INDUCTION SYSTEM ICING PROTECTION 
23,1419 ICE PROTECTION 
RE: FAR 2 5  APPENDIX C 
TRANSPORT AIRCRAFT: 
25.1093 INDUCTION SYSTEPl DE-ICING 8 P.NTI-ICING 
PROVISION 
RE: FAR 2 5  APPENDIX C 
RE: SNOW BOTH FALLING & BLOWING 
25.1403 WING ICING DETECTION LIGHTS 
25,1416 PNEUMATIC DE-ICER BOOT SYSTEM 
25.1419 ICE PROTECTION 
RE: FAR 2 5  APPENDIX C 
Figure 3 .  Current Airworthiness Standards 
0 FLEET PRODUCTIVITY 
@ CERTIFICATION PROCESS 
ALL-WEATHER OR NEAR ALL-WEATHER OPERATIONS 
LENGTH & COST 
I) ROTORCRAFT CERT I F 1  CAT1 ON 
S-76 
PUMA/SUPER PUMA 
Q12/214ST 
0 GA AIRCRAFT 
0 FAR 2 5  APPENDIX C 
LOW-COST, LIGHTWEIGHT ICE PROTECTION SYSTEMS 
Figure 4. Aviation Community Concerns 
30 
https://ntrs.nasa.gov/search.jsp?R=19860002273 2020-03-23T06:34:51+00:00Z
People in the avition community have told us they 
want all-weather or near all-weather operating con- 
ditions. The manufacturers have told us they are 
concerned that the length and the cost of the FAA 
certification process is too great. 
To date, unfortunately, we have not certified 
any helicopters for flight in known icing condi- 
tions. The French have certified the Puma. The 
manufacturer for the Puma Aerospeciale has come 
to the United States and asked us for certification 
for both the Puma and the Super Puma. Bell He- 
licopter has started flight testing for the 412 and 
214ST and intends to  get an icing certification for 
it, as does Sakorsky for the S76. General aviation 
aircraft is by far the largest and most rapidly grow- 
ing segment of the aviation community. They have 
informed us that they need low-cost, lightweight, 
easy-to-maint ain, low-power systems for their air- 
craft in order for them to fly efficiently. Manu- 
facturers have also told us some interesting things 
about FAR 25 Appendix C. This is a very strin- 
gent requirement. They would like to see if we 
could possibly relax that and give them a little 
relief. These are the aviation community needs. 
The flip side of this coin is what the FAA needs. 
2-3-83 FAA ADRINISTRATOR BRIEFING ON ATMOSPHERIC CHARACERIZATION 
8 LONG-RANGE P W .  
4-21-83 AVIATION STANDARDS 8 REGIONAL CERTIFICATION DIRECTORATES 
MEETING TO REVIEW PROGwvl PLAN. 
7-28-83 FAA AD9INISTRATOR BRIEFED ON ACTIVITIES CURREXTLY GOING ON 
IN GOVERNMENT-RELATED AIRCRAFT ICING PLAN. 
9-20/22-83 NATIONAL ICING RESOURCE SPECIALJSTS AND REGIONAL CERTIFICATIC 
DIRECTORATES REVIEW REQUIREENTS AND PRIORITIES FOR PROGFM 
PLAN * 
SCHEDULED FAA ADMINISTRATOR, NASA ADVINISTMTOR, CHAIRMAN FEDERAL 
ll-3-83 COFUlIlTEE FOR tlEEOROL0GICAL SERVICES 8 SUPPORTING RESEARCH, 
UNDEP. SECRETARY OF DEFENSE FOR RESEARCH 8 ENGINEERING WILL 
BE BRIEFED. 
As noted in Figure 5, the FAA needs several 
different things in order to do its job efficiently. 
One of the things we need to do is characterize 
the icing atmosphere, as well as to learn things 
about aircraft performance in known icing condi- 
tions. As a special interest, we also want to  take 
into consideration rotocraft needs. We would like 
to learn things about the use of thick fluids for de- 
icing as is currently being done in Europe. Our 
e CHARACTERIZATIONS 
- ATMOSPHERE 
- AIRCRAFT PERFORMANCE WITH SNOW/ICE ACCUMULATIONS 
- ROTORCRAFT PERFORWNCE WITH I C E  ACCUMULATIONS 
- EFFECTS OF UNDER-WING FROST 
- AIRFOIL  PARAMETERS SENSITIVE TO SURFACE ROUGHNESS 
- HIGHLY VISCOUS DE-ICING FLUIDS 
0 ANALYTICAL FIETHODS 
- DESIGN AND COMPLIANCE DEMONSTRATION 
e SIMULATION 
- ADEQUACY OF I C E  TEST F A C I L I T I E S  
- USE OF SII lULATION TECHNOLOGY 
0 UPDATED CERTIFICATION CRITERIA INCLUDING STANDARDS AND 
TEST PROCEDURES FOR : 
- ROTORCRAFT 
- TURBINE ENGINES 
- AIRCRAFT 
Figure 5. Federal Aviation Administration Needs 
program will also consider analytic methods to be 
applied in certain circumstances for certification. 
We also say that you can use simulation; but we 
really don’t set any guidelines, standards, or pro- 
cedures for you to follow which are acceptable to 
us. After we have done all these things, we need to 
update our standards, procedures and FARs for all 
of the above; i.e., rotocraft, turbine engines, and 
aircraft with fixed wings. 
Figure 6 summarizes the recent histoq of the 
FAA Aircraft Icing Program. 
Figure 6. Aircraft Icing Program 
On February 3, 1983, the FAA Administrator 
asked us to present him with a briefing on why 
we were doing atmospheric characterization. In 
that briefing, we also gave him the long-range plan 
which the FAA had developed. At that same time, 
the Administrat6r asked us to return in one year 
to discuss all developments which had been made 
within the Government dealing with aircraft icing. 
Within about two months, we had the Aviation 
Standards people and the Regional Certification 
Directorates a t  a meeting to review the program 
plan. We did go back in July of this year to brief 
the Administrator on all of the information we had 
(and we had researched this thoroughly) concern- 
ing all aircraft icing research and developments. In 
September 1983, we had a meeting of the Nation- 
al Resource Specialists and the Regional Certifica- 
tiou Directorates to review the plan and set the 
priorities within the program plan itself. We have 
also scheduled a meeting between the FAA Ad- 
ministrator, the NASA Administrator, the Chair- 
man for the Federal Meteorological Services and 
Supporting Research, and the Under Secretary of 
Defense, at which time they will be briefed on the 
same subject. 
31 
Figure 7 will show you a little about how 
we have organized the Aircraft Icing Program for 
the FAA. We have sections on Atmospheric Crite- 
ria, Procedures and Technology, and Simulation. 
Those three things are R &z D functions which will 
lead to a technology base to ultimately be used 
in the FAA regulatory base. We intend to work 
very closely within the government, with all the 
cognizant agencies, with the academic community, 
and with industry, itself, to see that the program 
really meets your needs, as well as meeting the 
needs of the FAA. We also intend for the program 
to put forth information, guidance material, etc., 
as information becomes available to us. We do 
not want to wait five years to have it all nice and 
tidy for you. That would not be very good for the 
people in the community. 
ATPaSPHERIC CRITERIA PROCEDURES 8 TECHNOLffiY SInULATlON 
0 SUPER-CWLED CLWD - UNDER 10,000 FEEl - OVER 10,000 M 
e SNOW 
0 FREEING PREClPlTATlON 
a nixm CWTIONS 
I ICE CRYSTALS 
I REGULATION 
* IZWISORY 
e EPUlPllENT CHARACTERISTICS * sRoUND FACILrTIES - FULL SCALE - S W  NODELS 
- TPNKERS 
- MTH PODELING 
- PROTECTION - DElEcTIDN - DISPLAYS e AIRBORNE FACILITIES 
CCUPUTER FACILITIES 
0 ADYAMCED CONCEPTS 
e OPEPATIOMS 
Figure 7 .  Aircraf t  Icing Research Program 
Functional Relationships 
No program is a real program without ade- 
quate funding (Figure 8). Over the next five years, 
FY 84-88, the FAA plans to spend a total of $5.3 
million in contracting funds to support this plan. 
It will also be supported with eight (8) senior spe- 
cialists/scientists cognizant in their fields. As we 
see progress in this program, we will readjust the 
resources and the staffing. 
N '03 w -05 '06 '87 '00 
CONTRACT FUNDS ( t K )  I50 EO0 1000 900 900 lOC0 
STAFFlNG t W ) 4  0 8 0 8 0 
Figure 8. Five-Year Funding Plan 
The FAA Program Plan outlined in Figure 9 
shows that when we characterize the atmospheric 
environment for icing, we are talking about super- 
cooled clouds above 10,000 feet. We have already 
completed the first phase of atmospheric charac- 
terization; i.e., super-cooled clouds below 10,000 
feet. We are also going to look at snow, freezing 
rain, drizzle, mixed conditions with super-cooled 
clouds and ice crystals; then we will look at ice 
crystals separately. The certification directorates 
have told us that it is most important for us to 
get not only CONUS data but world-wide data as 
well, because our aircraft fly world-wide, and we 
want the FA% to be able to cover all those condi- 
tions. Therefore, if we are going to relax the FAR 
25, Appendix C, we would like to know that our 
SUPER-COOLED CLOUDS OVER 10,000 FEET 
'SNOW 
FREEZING RAIN AND DRIZZLE 
MIXED CONDITIONS 
ICE CRYSTALS , 
INSTRUMENTATI OM 
- TEST 
- EVALUATION 
- OPERATI O M  
INTERNATIONAL DATA BASE 
Figure 9 .  FAA Program Plan 
planes would not fall out of the sky if they were 
flying over Norway. 
We are also developing something that is very 
important-an international data base. We are go- 
ing to be asking the industry as well as the depart- 
ments within the government to be contributing to 
this. There are many places with many different 
sources of data, such as the Bureau of Reclama- 
tion, DOD, and NASA. We would like to combine 
all of this information and start an international 
data base to characterize the atmosphere. As we 
evaluate and find holes in the data, we will initiate 
meteorological surveys in those areas in order to 
complete those characterizations. 
Ice protection is a very important part of the 
program plan. Figure 10 defines the areas into 
which the FAA will be looking and keeping abreast 
of these areas as things develop. Rather than wait- 
ing for a request to certify to come into the FAA as 
the manufacturers develop these systems that will 
be used, we would like to stay abreast of them and 
issue guidance material. Therefore, when some- 
32 
8 ANTI-ICING 
- FREEZING POINT DEPRESSANTS 
- ICE PHOBICS 
- THERMAL 
8 DETECTION 
0 CONTROL 
- SYSTEPI OPERATION 
@ DE-ICING 
- AIRBORNE 
* PNEUI"?ATIC 
* THERMAL 
* ELECTROMAGNETIC IMPULSE 
- GROUND 
* THERMAL 
* CHEMICAL 
0 FLIGHT TEST A\D EVALUATION 
Figure 10. Ice Protection System Technology 
one comes to us with a need for certification on a 
particular type of system, we will have done our 
homework in advance, eliminating a long wait to 
get a certification. Neither will we be confused 
as to the requirements for certification. We think 
we can cut the time down to certify an aircraft or 
rotorcraft if we do our homework first. 
We will also be publishing the guidance ma- 
terial as we get it. However, the FAA will really 
not be advancing the ice protection system tech- 
nology. We will be working with you as you de- 
velop the systems so that we can be aware and 
can be publishing our guidance material; however, 
we won't be trying to advance the state-of-the-art. 
We have stated that simulation can be used in or- 
der to meet some certification criteria. As shown 
in Figures 11 and 12, one of the things that we 
have to do now is to correlate the airborne facili- 
ties and the ground-based facilities with nature as 
we discover it through our atmospheric characteri- 
zation studies. We will then be issuing guidelines, 
standards, and procedures which can be used in 
order to obtain an FAA certification. We are also 
going to validate that those ground-based and air- 
borne facilities do, in fact, meet the guidance that 
has been set forth by FAA. In the analytic method, 
we will hope to be reducing the cost and length of 
0 AIRBORNE TEST FACILITIES 
- HELICOPTER SPRAY (HISS) 
- TANKERS (OTHERS) 
O GROUND-BASED FACILITIES 
- WIND TUNNEL 
- ENGINE TEST 
- LOW VELOCITY 
- ROTORCRAFT TEST RIGS (NASA TUNNEL) 
9 OSC I LLAT I NG 
* ROTATING 
0 CERTIFICATION 
- RATIONALE 
- STANDARDS 
- PROCEDURES 
- GUIDELINES 
0 VALIDATION 
Figure 11.  Correlation o f  Airborne and Ground- 
Based Faci 1 i t i  es 
0 DEVELOPMENT 
- MATH 
- COMPUTER MODELING 
ICE SHAPE PREDICTION 
AERODYNAMIC DEGRADATION 
* WATE,R DROPLET TRAJECTORY CODES 
* ICE ACCRETION CODES 
TRANSIENT HEAT CODES 
* SOLAR RADIATION (SIMULATIOW) 
Q HUf4IDITY EFFECTS (SIMJLATION) 
0 APPLICATION 
- DESIGN 
A I RFRAME/ENG I NE 
- EVALUATION 
- EXTRAPOLATION 
0 VALIDATION 
- A I RFO I L PERFORMANCE 
- ARTIFICIAL ICE TESTING 
- ICING SCALING LAWS 
- AIRCRAFT ICING HAYDBOsK 
Figure 12. Analytic Methods i n  the Cert i f icat ion 
Process 
33 
the certification process by using more of the an- 
alytic methods as we come to know more about 
them. NASA is the leader in this, as well as the 
academic community. They are the people who 
will help us learn more about analytic methods. 
We will also be updating things like the ADS-4, 
which is about 20 years old and really in need of 
updatipg. Figure 13 shows our schedule, drawing 
things together and putting them into perspective. 
The atmospheric characterizations that are seen 
here did not really begin until 1983. The super- 
cooled cloud and the snow did; however, the freez- 
ing rain, drizzle, ice crystals, mixed conditions will 
all begin in 1984. It is planned for them to go all 
the way through 1988 in order for us to obtain 
both CONUS and world-wide data. The proce- 
dures and the technology for the ground de-icing 
will be updating AC 20-117 to include things like 
thick fluids. The initial update of the Aircraft Ic- 
ing Handbook will not be a reprint but an updat- 
ing of the newest, latest technology that we can 
find, and that ought to be out within two years. 
The FAA will proceed on a bi-annual update plan 
henceforth. We will be doing the same thing with 
simulation technology. We are trying to put all the 
information into one spot, so an internally consis- 
tent document is available. 
As noted in Figure 14, the specific products 
with which we have promised to come forward 
are: 1) atmospheric characterization for super- 
cooled clouds over 10,000 feet by June 1985 (only 
CONUS) 2) an update to AC 20-117 by September 
1985; 3) an update of the Aircraft Icing Handbook 
by June 1986; 4) a simulator technology section of 
the handbook by September 1986. 
This morning we have looked at some of the 
statistics that prompted the FAA to put together 
an icing program. We have looked at some of the 
history from user needs; and now we have gone 
into detail through the program. Please feel free 
to contact me with any comments or criticisms or 
suggest ions. 
e AWSPHERIC CHARACTERIZATIONS - SUPER-COOLED CLOUD 
ABOVVBELOW 10,000 FT. REPORT JUNE 1985 
REVIEW UPDATE AC20-117 REPORT SEPTEpIB€? 1985 
o GROUND DE-ICING TECHNOLOGY 
o AIRCRAFT ICING HANDBOOK 
e SIMULATOR TECHNOLOGY AIRCRAFT 
JUNE I986 
ICING HAM)BOOK ENGINEERING 
SUMURY 
SEPTEMBER 1986 
ENGINEERING - SNOw SUrPnARY 
- FREEZING RAIN REPORT D E C W E R  1586 - MIXED CONDITIONS 
- WORLDWIDE 
e AVIDSPHERIC CHARACTERIZATION 
e AWSPHERIC CHARACTERIZATIONS 
Figure 14. I FAA Product Developments for FY 85/86 
Figure 13. Ai rcraf t  Icing Program Planning 
Schedule 
“OVERVIEW OF NASA’S PROGRAMS” 
A. Richard Tobiason 
I will try to give a general overview of NASA’s 
programs and be as brief as possible. It is ger- 
mane to the scope of what you will be looking 
at for the next few days. The good news is that 
we have 17 NASA representatives here from aero- 
nautics programs within all the centers who can 
help you through the next few days, and they are 
strategically plared on all of the committees. So, 
if you need any follow-up on what I’m going to 
discuss, they are here. I will identify them as I go 
through the presentation this morning. 
There is an aeronautics side of NASA as well as 
a ‘space” side. We are involved in things l i e  im- 
proving planes for both the civil and military com- 
munities in areas of speed, safety, world leader- 
ship, and what the problems of flight are and how 
they can be fixed. That is where we start; that’s 
why we have a charter. Our meteorology work is 
carried out in the Aeronautical Systems Division 
under the Subsonic Office. The meteorology work 
is really a subset of our safety program. I’m the 
Safety Manager with about $6 million of R & D 
34 


Overview of FAA's aircraft icing program

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