Chicago ? Boeing Co.’s interim CEO told employees Wednesday that the process to select a new chief executive officer for the aerospace firm would be “deliberate” and be expected to last for months.

James Bell, who was promoted to acting CEO March 6 after the ouster of Harry Stonecipher, told Boeing workers in an internal message that “there will be no change in strategy, no reversals of business decisions” during his short tenure.

Bell, who also remains chief financial officer and is not a candidate for the long-term CEO’s job, said change was not necessary because Boeing’s operational and financial performance was “the strongest it’s been in some time.”

Boeing’s board named the 56-year-old Bell to the interim post after forcing Stonecipher to resign, citing improper behavior related to an affair he had with a female company executive. Company sources have said the ouster was deemed necessary because of graphic e-mail exchanges between the two at a time Boeing’s ethical conduct was under heavy scrutiny following two defense contract scandals.

The woman remains a Boeing employee while the company completes an internal investigation into the episode.

In his first companywide comment as president and CEO, Bell did not address specifics of the recent turmoil but noted it has been “an intense and busy 10 days for all of us.”

“In the months ahead, there will continue to be speculation in the media about who the new CEO will be,” he said in the message to Boeing’s 160,000 employees. “The Boeing board of directors, led by Chairman Lew Platt, is following a thorough, deliberate process to select the best leader to take Boeing forward.”

The Chicago-based company has two strong internal candidates to succeed Stonecipher — Alan Mulally, who heads the commercial aircraft unit in Seattle, and Jim Albaugh, head of the St. Louis-based defense operation. But after seeing the last two CEOs depart because of scandals — Stonecipher and Phil Condit, whom he replaced in December 2003 — the board likely wants to be extra cautious in the selection process in order to avoid a recurrence. Mulally is a graduate of Lawrence High School and Kansas University.

Boeing officials have declined to discuss the selection process except to say both internal and external candidates will be considered.

The company’s defense business has continued to prosper through controversy, with revenues registering double-digit gains in each of the past two years. Profit margins and orders are on the rise again in the commercial jet-making unit. Spokesman Todd Blecher said Boeing had received a total of 226 orders or commitments in 2005 for its aircraft — all but six for its 737 and planned 787.

Boeing shares fell $1.71 to close at $56.77 in Wednesday trading on the New York Stock Exchange. The stock is up 9.7 percent this year and trading near a 3 1/2-year high.