DingerX's Journal: F-22 Navigation Glitch: "It worked fine in the lab"

IFENs aren't the only computer system you can crash in flight, evidently. The shiny-new F-22 raptor arrived in Okinawa this weekend, the first overseas deployment for the USAF's most advanced and most expensive fighter. The arrival was a week late, due to a software glitch that at the time was unspecified, but required all six F-22s to turn back.
A week later, a purportedly unclassified document is making the rounds of the internet that suggests that inadequate testing of navigational software resulting in a bug bringing down all but the most basic flight controls of all aircraft.

Subject: F-22 AEF Deployment

Date: 12 Feb 07

To: CC

Info: CV, DS

Narrative:


1. A 1st Fighter Wing AEF 6-ship (Petro 91) departed Hickam AFB enroute to AEF location on 10 Feb. Approximately 4 hours into the mission and coincidental with crossing over the International Date Line, all six aircraft experienced a significant avionics failure including:

Both GINS 1 and 2 Fail

FLCS Degrade

Radar Fail

Fuel Degrade

Loss of all attitude references

Loss of Flight Path marker

Loss of all navigation aides (TACAN, ILS, Computed, etc.)

Loss of all heading indications

2. Aircraft communications were available via backup radio only. Only navigation available was via cockpit airspeed and altitude indications (both deemed accurate). All other aircraft systems, to include engines, electrical system and air refueling, were nominal.

3. Flight Lead, Lt Col Tolliver, initiated via the tanker a CONFERENCE HOTEL (CH) call with LM Aero. All CH team recommended workarounds (avionics restarts, date and time resets, etc.) did not resolve the problem.

4. Lt Col Tolliver assessed pressing to the AEF location but decided to turn back and return to Hickam. He also directed the second deployment cell, a 2-ship approximately one hour behind him, to return to Hickam. NOTE: This 2-ship never crossed the International Date Line.

5. Enroute back to Hickam, after crossing back over the International Date Line, avionics restarts were unsuccessfully attempted.

6. All aircraft successfully recovered at Hickam, shut down (cold iron), restarted engines and all avionics malfunctions cleared.

7. An F-22 Crisis Management Team (CMT) has convened. Two telecoms (1300 and 1700 EST) were conducted on 11 Feb. Participants included F-22 Program Office, LM, Boeing, NG and A8F personnel.

8. The F-22 Program is working 24/7 to resolve this issue. Both F-22 avionics integration labs (RAIL and AIL) have successfully duplicated the problem. The problem resides within the GINS software when the aircraft transitions between East/West Longitude. NOTE: Most RAIL and AIL testing simulate GINS inputs and past testing discovered no issues with over flying the Dateline or Poles. It took testing this weekend using actual GINS hardware and software to duplicate this problem.

9. A fix for this software problem has been developed at NG and currently is being evaluated in the RAIL. We should find out at our 1300 CMT telecom today if this fix works.

10. This fix will require an OFP update to be loaded on the aircraft. Currently no IMIS OFP loading support is on-site at Hickam. 1 FW IMIS was previously deployed to AEF location.

11. F-22 Program currently expects software fix, OFP loading hardware and LM support team in place at Hickam by mid-week. Aircraft possibly will be able to depart Hickam for their AEF location by the end of the week.

12. Updates to this issue will be provided as additional information becomes available.

Translation: The navigational system (Global Positioning Inertial Navigation Systems (GINS)) had never been physically tested crossing the date line, but only on simulated real-world inputs. When it crossed the date line for the first time, it crashed, as did the backup, bringing down with it all navigational systems and much of the aircraft's instrumentation, leaving them with backup systems reminiscent of a Cessna 172 (without the navigational stack).

What sort of software engineering is that, where the failure of a one element can bring down the whole avionics suite?

That's just scary.

[Short Circuit]

That's just scary; It would prevent rapid deployment of F22s westward. To get to Japan, the planes would have to hop across the Atlantic, and then across Eurasia.

Re:

[CoderJoe]

From the sound of things, leaving the Western Hemisphere would be a problem, no matter the route.

The problem resides within the GINS software when the aircraft transitions between East/West Longitude.

The software would transition between east/west longitude crossing the IDL (or 180 degrees longitude), 0 degrees longitude, as well as going directly over the poles. I wonder if they thought to test latitude transitions with the real hardware while they did the longitudinal tests.

F-22 software glitch

[Scott7477]

Thanks for the link. I'm not too worried about the glitch, though. My read on this is that the deployment to Okinawa was basically a shakedown operation, the point of which is obviously to identify glitches in a test situation. It's not surprising that there would be software errors; the real story is that unlike mass market software such as MS Windows, the vendor that wrote the F-22 code goes back and actually fixes the code. The article stated that the F-22 squadrons aren't expected to be "operational