Boeing is under growing pressure from unions to disclose the extent and funding source of its executive pension plans.
SPEEA is concerned the Boeing's pension programme, relied upon by 21,400 technical employees, is secretly being used to finance executive retirement benefits.
The union formally requested the information from Boeing after a recent investigative report by The Wall Street Journal uncovered allegations of US corporations funding executive pensions by funneling funds through regular employee plans.
This practice formally weakens employees' pensions while allowing corporations to take advantage of huge tax benefits not normally available for executive plans.
The report called the pension maneuvers by corporations a "dubious use of tax law that risks harming regular workers".
SPEEA executive director Ray Goforth said: "Benefits consultants advise companies to keep quiet about these schemes to avoid employee backlash.
"SPEEA demands to know if Boeing is sacrificing the pensions of regular workers to benefit executives."
Boeing spokesman Tim Healy said: "Boeing doesn't raid workers' pension funds to pay executive pension benefits and nor does it make the kinds of transfers described in the Wall Street Journal."
Boeing is also set to phase out its traditional pensions and put new workers into a 401(k) plan. The union said the contribution was half the value of present pension contribution and, in addition to reducing corporate expenses, the plan shifted all risks and maintenance of retirement onto the employee.
Healy said: "Boeing has announced a plan to have non-union employees hired after 1 January 2009, covered by an improved defined contribution plan (improved over what non-union employees get now) and no longer covered under the traditional defined benefit pension.
"Among Boeing employees not covered under this plan for future non-union employees are 26,000 machinists covered under a contract currently being negotiated with the International Association of Machinists.
"We have proposed a new DC plan for these machinists in a new contract to take effect 4 September, but this must be bargained with the union. We have talked in general terms about a new DC plan for more than 20,000 SPEEA engineers as well, but we have not proposed anything specific."
Jonathan Stapleton asks whether newly-accredited professional trustees should be a statutory fixture on pension scheme boards.
Savers are being warned by the Insolvency Service to guard their pension pots from investment scammers and negligent trustees as it winds up 24 companies.
Respondents say they should only be required in certain situations as the system is not broken.