Challenger 604 off runway in Almaty

[Dinger]

SEASPRAY......arrogance? I am pointing out the fact that a clean wing is not something that you compromise on...regardless of what aircraft you fly. Do you take off with contamination on the wing?

GLEX....I believe 1000+ hrs PIC in Challengers gives me enough experience to post here. You may not agree with my posts, but I most certainly am qualified to sit at the adult table.

 

[GVFlyer]

SEASPRAY......arrogance? I am pointing out the fact that a clean wing is not something that you compromise on...regardless of what aircraft you fly. Do you take off with contamination on the wing?

Competent, steely-eyed Air Force pilot that he is, I don’t think SeaSpray is qualified to fully answer your question about GV wing design.

As a part of the GV flight test certification program, I’ve flown the jet with heavy natural ice and extreme ice shapes simulating natural ice deforming lifting surfaces in all modes of flight.

Certification of the GV was the most extensive application ever made of the NASA Lewis ice accretion code LEWI3DGR. Certification of the jet was obtained under FAR 25.1419. We had a dedicated test article for ice testing and certification. That jet now flies for an operator out of Teterboro.

Analyses were performed to model water droplet impingement on lifting and nonlifting surfaces including both those protected and unprotected from ice accretion.

Heat transfer rates for treating leading edges were determined from dry air flight testing. Ice shapes were calculated and fabricated for artificial ice shape testing.

I flew flight tests with artificial ice shapes deforming both lifting and non lifting surfaces to verify aircraft performance with heavy ice accretion to include take-off modes. You would not believe the size of some of these ice shapes. It really makes you a believer in the Gulfstream.

Zero-g horizontal stall pushover maneuvers were also flown in the GV. The National Aircraft Certification Office of Transport Canada did not require these tests of the Global Express. As a matter of fact, the Global had a difficult time passing the tests that were required.

We flew an extensive series of test flights into known natural icing conditions in all flight modes to reaffirm aircraft performance and validate the ice protection system design. Flights into natural ice were made because the rules had changed to where we could no longer fly behind a tanker streaming water to measure flight qualities with heavy ice accumulation.

FAA requirements for ice protection for Part 25 aircraft address engine icing and airframe icing separately. Paragraphs 25.903(a) and 25.1093(b) are mandatory requirements primarily for protection against engine ice ingestion and operation in falling and blowing snow. During this testing BMW Rolls Royce dismissed 2 inch hailstones as “Trivial” in their Engine Certification Reports.

Airframe icing is addressed under FAR paragraph 25.1419. Compliance with this paragraph is optional, but we voluntarily met its requirements as a part of our flight test program to become Flight Into Known Icing (FIKI) certified.

Principally because of its wing and useful payload at 51,000 feet, the GV was selected by the National Center for Atmospheric Research (NCAR) for its High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) aircraft. This required another round of ice testing because of the addition of a revised radome, numerous fuselage appendages and wing stores.

Again the GV was able to safely fly with ice shapes simulating heavy ice accumulation on these protruding surfaces.

No one here is suggesting that pilots abandon safe operating practices in any aircraft, but if you find yourself in a serious icing situation not of your own making, it is nice to know that your jet will carry you through it safely.

In my view, Gulfstream’s 41 year record of no icing mishaps makes a significant statement about the inherent safety of the design.


GV





~

 

[Dinger]

Though I am very impressed with your depth of knowledge of the certification process as well as the real life limitations of the airfoil of Gulfstream products, my question was posed to Seaspray in the context of deciding whether to de-ice or not if there is wing contamination prior to departure.

As average-Joe pilots, there is a reason we don't have, nor should have, the depth of knowledge a manufacturers test pilot is required to have. If we knew the actual contamination a wing will fly with during the departure phase of flight....well, there would be too many pilots pushing the envelope.

Never in my previous posts did I say the Challenger was equal to, or better than the Gulfstream. My emphasis was on pointing out that pilot error...in the takeoffs with wing contamination it was an error in judgement.....has been a major factor in the Challenger accidents/incidents.

Correct me if I am wrong, but there has yet to be a Challenger accident (not including contaminated wings) that can be directly linked to the wing design! Keep it clean and it will fly (unless, of course, you excede the C.G. envelope as was the case in Wichita).

 

[GVFlyer]

You are correct. There have been no other types of accidents attributed to Challenger wing design. The Challenger uses a high wing loading, buffet limited, supercritical wing design and is subject to the limitations of that class of wings.

The Challenger at Wichita did not crash because it was out of CG per se. It crashed because of the TP's over rotation compounded by inadequate baffling in the Challenger multiple tank fuel system causing rear fuel movement and subsequent exceedance of the rear CG limit followed by departure from controlled flight.

"The National Transportation Safety Board determines that the probable cause of this accident was the pilot’s excessive takeoff rotation, during an aft center of gravity (c.g.) takeoff, a rearward migration of fuel during acceleration and takeoff and consequent shift in the airplane’s aft c.g. to aft of the aft c.g. limit, which caused the airplane to stall at an altitude too low for recovery. Contributing to the accident were Bombardier’s inadequate flight planning procedures for the Challenger flight test program and the lack of direct, on-site operational oversight by Transport Canada and the Federal Aviation Administration."

Experimental Test Pilot Eric Fiore, Experimental Test Pilot Bryan Irelan, and Flight Test Engineer David Riggs were esteemed members of the test community.

The Challenger that crashed at Teterboro 2 February 2005 was out of CG. Here’s an excerpt from the NTSB’s findings.

"The National Transportation Safety Board determines that the probable cause of the accident was the flight crew’s failure to ensure the airplane was loaded within weight and balance limits and their attempt to take off with the center of gravity well forward of the forward takeoff limit, which prevented the airplane from rotating at the intended rotation speed.”

http://www.hasbrouck-heights.com/news05/teb1_05.shtml


GV

 

[Dinger]

GVflyer, in your first line in my response to SEASPRAY you said...."...I don't think SEASPRAY is qualified to fully answer your question about GV wing design".

I did not have a question about the wing design.....my question was if he took of with wing contamination! In my view....and, hopefully, most pilots' view....you just don't do it.

We are not test pilots....we are pilots that operate at the lowest common denominator!

 

[hawkerjet]

I think we're starting to beat a dead horse here. I believe we all can conclude that the Challeger 600 series wing is the achilles heal for the aircraft. It is a safe wing when flown when flown IAW the manufacturer's AFM and isn't very forgiving in icing conditions.

 

[SkyGirl]

You said it! With the icing accidents, the center of gravity accidents, the CRJ take-off accidents and whatever the Pinnacle accident was, the Challenger series aircraft appear to be terribly unforgiving airplanes.

_SkyGirl_

 

[Dinger]

The END!

 

[TXGold]

I seem to remember the Birmingham accident aircraft rolled left due to the heat the right wing absorbed from the APU exhaust during ground ops prior to departure.

The END!!!

 

[G100driver]

Soooo how about flying a Falcon 2000 over water?