Avionics Mobile Service has obtained the first UK CAA RVSM certification on a British Aircraft Corporation BAC 1-11 475 series aircraft. Peter Robinson, engineering manager at the company, reported that the final RVSM system calibration and testing was completed on August 5.

The following day, an RVSM verification flight was conducted

over the UK HMU monitoring station near Strumble.

“The total ASE was reported as minus 12 feet at FL300 and + 33 feet at FL310. Captain Alastair Taggart reported on landing back

at Bournemouth International

airport, saying: “that’s the finest altimetry system I have had the pleasure to fly with.”

The project started back in January 2002 when Avionics Mobile were first approached by several BAC 1-11 owners who requested RVSM certification for their aircraft.

“Our first task was to prove that an autopilot system designed and

built back in the early sixties could

in fact actually meet the

stringent requirements for RVSM Altitude Hold, these limitations being +/- 65 feet maximum deviation in

the cruise”.

In April 2002, Avionics Mobile installed a GMU and carried out a full flight envelope flight test in order to evaluate the overall performance of the Elliott 2000 split Axis Autopilot system. This was a pre-requisite to any further RVSM work, and the results proved that the autopilot was in fact capable.

Having submitted its findings to the CAA and proved the autopilot, the next task was to choose a partner to complete the RVSM flight testing.

“We partnered with Aeromech Inc in Everett, Washington USA as

they had flight tested over 150 airframes seeking RVSM compliancy and we had worked together successfully on previous RVSM projects,” said Robinson.

So the aircraft was flown from the UK to Opa Locka in Florida and all of the necessary flight-testing was completed in March of this year. The next major step was for Avionics Mobile to select and install a dual RVSM compliant equipment installation. Innovative Solutions & Support Inc, based in Exton, Pennsylvania USA was selected from a number of potential suppliers.

“The IS&S air data display unit (ADDU) is a versatile, light weight, innovative product with proven reliability and it provided us with two full ARINC 429 digital air data computer/altimeters, all this contained within a 3” ATI package,” said Robinson.

The RVSM certification on the BAC 1-11 brings to an end a two-year avionics update programme with TCAS, dual FMS, 8.33 and FM Immunity upgrades. “Short of installing some Flat Panel LCD displays in the instrument panel,

we have now dragged the 1-11

flight deck into the 21st Century,” Robinson added.

Since the programme started, five more European BAC 1-11 operators have signed up for RVSM and Avionics Mobile has started receiving enquiries from operators in the US.

“Along with 8.33, FM Immunity,

B-RNav, EGPWS and TCAS we have had experience in RVSM installation and certification on the DC 8, B727, B737, and Citation Jet,” said managing director Jim Herbert.