My experience w/ EMB radar (4years/3000 hrs.):
The Radar installation itself (Honeywell Primus 660/880) works about like it's supposed to. The problem is that this radar system is more appropriate for a different airframe.
The EMB airframe has several deficiencies that make it challenging for this radar istallation to perform consistantly and effectively.
On the groud BEFORE departure it works acceptably well to paint WX (3-4 degrees tilt UP, preferably in the 25 mile range).
After takeoff (until about 6-7000) a tilt of about 6 degrees (or more) is required to minimize ground clutter from a small 12-inch dish but, even then some performance is lost to dispersion.
In flight at low and middle altitudes, it also works REASONABLY well when painting WX (especially strong well defined returns with steep gradients) when you are CLEAR of precipitation.
Once in precipitation OR CHARGED CLOUD, is when this installation MAY lose considerable effectiveness because of the Airframe defeciencies noted above which involve two areas.
1. Radome shape, construction and condition.
2. The marginal ability of this airframe to dissipate static electricity (real reason for most of the lightning strikes that this aircraft takes and yes it does have the HIGHEST strike occurance of any aircraft out there).
The radome is a honeycomb-type composite radome treated with anti-static paint and is required to be clean, dry and free of excessive wear or damage (even a little !).
Radome related factors that will degrade radar performance include :
- Water film on the radome(or ice at high altitude).
- P-static on the radome (especially with EVEN A LITTLE missing paint)
- Micro holes caused by electrostatic discharge (which allow water to seep into the inside of the radome)
- Lightning strike damage
- Wear or damage to the clear abrasion boot.
Any single one of these factors (and especially a combination of them) will SIGNIFICANTLY degrade this radars performance ESPECIALLY while flying through precipitation.
The other area of airframe static is just as degrading to the radar as it is to the COMM radio function.
If you look at this airframe you can see a lot of pointy edges (nose, tail and wingtips) that make it a perfect static holder in flight despite the massive efforts to help it discharge static.
Most lightning strikes are because the aircraft holds a great deal of accumulated static (difficulty in discharge during high accumulation situations) while clear of actual thunderstorms in oppositely charged air, not because a thunderstorm was actually penetrated.
Many pre-mature thunderstorms with tops close to 30,000 feet will not have enough moisture condensation yet to truly be painted by this radar, while a Boeing, Airbus or MD-80 installation will give sooner warning because of its larger dish and blunter, less sensitive radome as well as easier airframe static dissapation capabilities.
Some things I do to minimize my problems :
1.) Get the "big picture" before departure.
2.) Preflight the radome CLOSELY (Very Important).
3.) Use the radar as much as possible before take off.
4.) Climb as quickly as possible to 7-8 thousand feet (if entering precip) because of pitch attitude/dispersion.
5.) Use the 25 mile range (or closer when flying thru precip).
6.) Use the TCAS to see where other aircraft are in relation to what my radar is painting (I especially like the 20/BELOW setting because frequently other aircraft like slower props may be visual below the cells while I'm relying solely on radar due to IMC).
7.) Stay visual is long as possible and use those times of visual ability to make deviations that might be advisable without assistance from the radar.
8.) Fly VERY cautiously at night because of the reduced visual capability.
9.) When flying thru precip, with embedded activity in the vacinity and COMM static is present, recognize that your radar may be equally effected.
10.) When in doubt as to the ride, sloooooooooooow the airplane down (it also reduces static build-up).
11.) Hope for the best with the element of luck.
Anyway, just my .02 cents.
Other than that and a pathetic flight director (EICAS software versions below 18.5), it's not a bad aircraft.
There is one other little item that I'd be curious to hear if other EMB drivers have experienced (or heard ablout).
Has anyone had the hydraulic rudder system disengage during landing (subsequent EICAS "HYD SYS 1-2 INOP") in gusty crosswinds ?
